October 12, 2018

A Look at Tropical Storm Michael's Unexpectedly Intense Winds in Central N.C.

More than a million people in North Carolina and Virginia are without power this evening as energy crews try to repair the damage caused by Tropical Storm Michael's passage on Thursday. The Piedmont region was particularly hard hit, unexpectedly experiencing high-end tropical storm conditions for more than an hour during the height of the storm. I live in Rockingham County, North Carolina, one of the hardest-hit areas and a county that saw nearly 70% of its residents lose power during the worst of the storm.

Nasty conditions were in the forecast for central North Carolina for days before the storm. The main risk was always going to be flooding from heavy rain, which we saw in abundance. Tropical storm warnings were in effect for many inland locations to reflect the risk for high winds during the storm, but the warnings were mostly confined eastern parts of the state in the lead-up to the storm on Thursday and only expanded westward on Thursday morning.

The storm here in Rockingham County was relatively tame for most of the day. It poured all day. The winds picked up a bit in the early afternoon hours as the center of Tropical Storm Michael drew closer to the area. I even tweeted a video of the heavy rain and breezy conditions to make note of how well the winds were behaving despite the heavy rain and our proximity to the center of the storm.

That didn't last long.

I was in the living room around 3:00 PM when I heard a loud thunk on the roof. I turned around to look out the window and saw a cloud of leaves and debris swirling over our apartment building. I got away from the window in time to see the trees twisting and bending like I'd never seen during any of the awful storms we've had in the past. The sound of the wind was horrendous, made even worse by the howling whistle coming through the cracks in the windows and front door.

The wind grew stronger as the minutes wore on, at first in buffeting gusts but eventually settling into a steady, constant roar. Shingles and window shutters peeled off of our apartment buildings. The blizzard of leaves and branches and occasional roofing debris and building material whizzed by the window and over the roof. The power flickered on and off for a while before finally giving out about 30 minutes into the ordeal. The wind finally started to calm down after almost an hour.

I had to go back and piece together a timeline to make sure my perception of time wasn't biased by my anxiety. It really did last about an hour. The strongest winds began right around 3:00 PM. I first tweeted about the kicking winds at 3:02 PM. The National Weather Service issued a severe thunderstorm warning about ten minutes after the damaging winds started, alerting Rockingham and Caswell Counties, as well as several counties in Virginia, of the potential for damaging winds of up to 70 MPH. The Storm Prediction Center received a report of a possible tornado in Reidsville at 3:20 PM. A tornado warning was issued at 3:42 PM for more areas of rotation spotted on radar. I noted that the wind had finally died down around 4:00 PM.

Nearly 70% of Rockingham County's 50,000 electric customers lost power at the height of the storm, and more than half still had no power by midnight the following day. The entire City of Danville, Virginia, lost power for the night after the storm. Many counties in central parts of North Carolina and Virginia saw more than half of their residents lose power as a result of the intense winds on Thursday afternoon, according to PowerOutage.US.

I don't like to see the word "unexpected" in weather reporting. Many weather events really aren't unexpected. The folks in harm's way who didn't expect a natural disaster likely weren't listening to forecasts and warnings ahead of the storm. However, I feel comfortable using "unexpectedly" in the headline of this post because the extent of the damaging wind event we experienced was not well-forecast nor was it well-warned in the areas struck by the destructive winds today.

Forecasts regularly mentioned the potential for wind gusts as high as 40 or 50 MPH as the storm passed to our southeast, but what we experienced went well beyond that—for all intents and purposes, parts of the Piedmont in North Carolina and Virginia experienced the winds of a high-end tropical storm for an hour. On top of that, the hardest-hit counties were never placed under a tropical storm warning, and the severe thunderstorm warning for 70 MPH winds wasn't issued until about 10 minutes after the damaging winds started howling.

The National Hurricane Center found Tropical Storm Michael's maximum sustained winds around 50 MPH as the center of the storm passed through North Carolina on Thursday afternoon. The agency analyzed the extent of its tropical storm force winds reaching to the southeast of the center toward the coast.

If that wasn't the bulk of the storm, then what was it?

The windstorm we experienced in north-central North Carolina was more akin to a persistent severe thunderstorm than a full-fledged tropical storm. The winds in a tropical cyclone are driven by the storm's intense pressure gradient. Air rushes in to fill the void left by the low pressure in the middle of the storm, creating the destructive winds in a storm.
Source: Tropical Tidbits

The winds in a tropical cyclone are much stronger just above the surface than they are at the surface. Winds grow stronger with height because they're not limited by the effects of friction. The winds at the 850 millibar level—a few thousand feet above the surface—were blowing as strong as 70 to 80 MPH as Michael moved across North Carolina.

What appears to have happened is that a line of very heavy showers—essentially, thunderstorms without thunder—formed on the northwest side of Tropical Storm Michael's center of circulation as it passed between Greensboro and Raleigh on Thursday afternoon. This enhanced convection was able to mix-down those powerful winds from just a few thousand feet above the surface. The persistent nature of the thunderstorms caused a prolonged period of high-end tropical storm force winds across parts of the Piedmont in North Carolina and Virginia.

The National Weather Service will conduct a survey in Reidsville on Friday to determine if any of the damage was caused by a tornado. I wondered during the storm whether or not we'd been hit by a tornado right when the winds start, but I'd be surprised if the survey crew found that the damage was caused by anything more than straight-line winds. Most of the damage to our apartment complex was superficial—shingles and shutters torn and tossed, torn vinyl siding, tree damage—but there are lots of reports of more serious damage elsewhere around town and around the county.

The seriousness of the destruction along the Gulf Coast dwarfs what we experienced here in central North Carolina, but such intense winds for such a long period of time is a heck of a thing to experience when you're not expecting it.

(Top Image: CIRA/RAMMB)

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October 10, 2018

Here's Why It's So Hard to Verify a Monstrous Hurricane's Maximum Winds

Hurricane Michael made landfall today near Panama City, Florida, with maximum sustained winds of 155 MPH. Its winds were just a few ticks short of a top-of-the-scale category five, but that doesn't matter to the folks in the path of the storm. This hurricane is an unprecedented disaster, and the pain and suffering for residents in the affected areas is only just beginning. The pictures and videos we saw of the damage from extreme winds and storm surge will only get worse as folks in the hardest-hit areas start to check in with the outside world.

As we see with every storm, the folks who come out of the woodwork on social media after every natural disaster are starting to bray their disapproval with the process that goes into recording the strength of the storm. They like to claim that the maximum winds in the storm were really weaker than advertised and its "official" maximum winds were hyped up for ratings, politics, face-saving, or whatever affirms their conspiracy du jour. We're already seeing that trash talk start before the storm surge has even receded on the Florida coast. I normally wouldn't indulge the nonsense so soon after the disaster, but their concern trolling raises a legitimate question:

Why is it so hard to verify the maximum winds of a hurricane?
Source: Tropical Tidbits
Meteorologists have an enormous array of tools available to them to help survey the world around us. You can use advanced satellites, high-resolution Doppler weather radar, a relatively dense network of observing stations on the ground, and even data collected by airplanes, ships, buoys, and oil rigs to collect information about the strength of a hurricane.

The experts at the National Hurricane Center use all of those methods to determine the intensity of a tropical cyclone leading up to and at the point of landfall. These intensity values are reevaluated at the end of the season to check for accuracy and correct for any mistakes. The above graphic shows data plotted from a reconnaissance aircraft as Michael made landfall on Wednesday afternoon.

While we have all those tools available for analysis, it's hard to directly measure the strongest winds experienced at ground level.

Let's start small by thinking about tornadoes for a second. We can get a decent profile of a tornado based on damage surveys conducted by meteorologists in the days after a storm. Experts surveying the path of a tornado can use damage to structures, vehicles, vegetation, and even the ground itself to estimate the winds in a tornado. We know the EF-5 tornado that tore through Joplin, Missouri, had winds stronger than 200 MPH because, not only did it simply wipe away entire neighborhoods, but it did unfathomable damage like compromising the structure of a five-story hospital and tearing away concrete parking blocks that were staked to the ground with two reinforced steel rods.

We know a whole lot about tornadoes despite the fact that few of them ever directly hit a weather station. The odds of any one tornado directly hitting a weather station are astronomical due to their relatively tiny size. Even in Oklahoma, which is the most tornado-prone region in the world, only four weather stations out of more than a hundred have been struck by tornadoes in the past decade.

Since hurricanes are many hundreds of times larger than tornadoes, any given landfalling storm will hit dozens of weather stations along its path. That gives us a lot of information about a storm as it comes inland, but it doesn't mean that the strongest winds in a storm will hit an unlucky anemometer.

The strongest winds in a hurricane are confined to the eyewall, or the thunderstorms that wrap around the center of circulation. Even though Hurricane Michael had maximum sustained winds of 155 MPH, it doesn't mean that all of the winds in the eyewall were 155 MPH. The peak winds occur in only a very small area of the eyewall, an area that usually only covers a couple of miles of real estate. This maximum is typically located on the right side of the eyewall relative to the forward motion of the hurricane. If the hurricane is moving north, the strongest winds will occur in the eastern eyewall because the winds are flowing in the same direction as the hurricane's forward motion.

It's hard to receive direct ground confirmation of the maximum winds in a hurricane because the maximum winds only encompass a tiny portion of the overall storm, and you would have to get incredibly lucky for that small area to pass directly over a weather station with an anemometer that survives the flying debris and the sheer stress of the wind. Not even during 1992's Hurricane Andrew did a weather station directly sample the storm's maximum winds, despite the category five hurricane's eyewall striking a heavily-populated part of southern Florida, including the National Hurricane Center's own office.

We've seen lots of pictures and videos of horrible damage around Panama City and Panama City Beach this evening. Tyndall Air Force Base, which fell under the northern part of the eyewall and saw sunlight as the eye passed overhead, measured a wind gust of 129 MPH during the worst of the storm. Florida State University's campus in Panama City saw a 116 MPH gust during the passage of the eyewall.

Panama City and Panama City Beach were on the western eyewall. Tyndall Air Force Base was on the northern eyewall. There's so much wind damage in those areas that it looks like a bomb went off.

Here's a look at the damage in Panama City:

Veteran hurricane chaser Josh Morgerman tweeted this evening that he was "literally shocked" at the scope of the damage around Panama City.

But Panama City didn't even see the worst of Hurricane Michael's winds.

However, Mexico Beach did:

Pictures and videos from the hardest-hit areas are hard to come by because the power is out and cell phone towers have spotty (or no) service. It'll take a couple of days to get a full idea of the damage inflicted by the hurricane's eastern eyewall.

There were no readily-available weather stations in the eastern eyewall of Hurricane Michael to accurately measure the storm's strongest winds. At least, none that we know of. There could be storm chasers' anemometers or personal weather stations that were located smack in the eastern eyewall that we'll get data from in the coming days and weeks. Meteorologists will be able to use wind damage and storm surge measurements to estimate how strong the winds were as the storm came ashore.

This was an unprecedented hurricane for this part of the country. The Florida Panhandle simply hasn't seen a hurricane this strong since accurate recordkeeping began in 1851. It's going to take a while to account for all the damage. It's likely that people died in the wind and storm surge. It will take years for the area to recover from the storm.

But to say that it wasn't as strong as meteorologists advertised—that they purposely overinflated the numbers—based on a handful of wind reports from the northern and western eyewall is just bunk. It doesn't take direct, observed confirmation of wind speeds to know that this storm was everything they advertised and more.

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Hurricane Michael Nearing Landfall With 150 MPH Winds

Hurricane Michael is just hours from landfall near Panama City, Florida, with maximum sustained winds of 150 MPH. The storm's minimum pressure is now among the top-five lowest for any storm at landfall in the U.S. on record. Its winds are now on-par with those of Hurricane Charley as it made landfall south of Tampa in 2004. No storm this strong has ever struck the Florida Panhandle since reliable records began in the 1800s. We're in uncharted territory now.

My update from last night still mostly holds true. The wind damage and storm surge will be even worse now. It will take longer for the storm to shed its strength as it pushes inland, expanding the area that will see tornado-like wind damage from the core of this hurricane.

Power outages will certainly last weeks—likely months—in the hardest-hit areas. Even inland areas will see weeks-long power outages. Those who stayed (either by choice or circumstance) will face prolonged suffering due to the damage; the lack of electricity and running water, no ability to pump fuel, and shuttered restaurants and stores will leave people in the affected areas completely reliant on their own supplies or those handed out by crews and organizations after the storm.

You still have some hours left if you're in parts of Georgia, South Carolina, and North Carolina, and need to prepare for power outages or flooding. The storm will move at a decent clip once it's inland, but it'll be a sharp sting when it hits.

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Hurricane Michael's Winds Are Forecast to Reach Category Four Intensity by Landfall

Hurricane Michael is an extremely dangerous storm in the eastern Gulf of Mexico this evening. The National Hurricane Center now expects its maximum winds to reach category four intensity by landfall on Wednesday afternoon. The storm will be one of the strongest ever recorded at landfall on the Florida Panhandle, and one of the strongest landfalls we've ever seen so late in the year. Michael poses an extreme risk to anyone who chose (or had no choice but) to stay ahead of the storm's expected landfall near Panama City on Wednesday.

The Forecast

Hurricane Hunter aircraft flying through Hurricane Michael on Tuesday night found that the storm's winds had rapidly intensified to category four status. The storm has maximum sustained winds of 130 MPH with higher gusts. The storm's pressure fell to 943 millibars, down from 970 millibars this time last night.

The forecast at 11:00 PM EDT Tuesday shows Michael making landfall around Panama City, Florida, on Wednesday afternoon, with category four winds. The storm will steadily weaken once it's inland, but it won't wind down immediately. Hurricane force winds are still likely in the eyewall as the center of the storm moves into southwestern Georgia.

This hurricane is the real deal. It will take a major disruption in the internal organization of the hurricane (an eyewall replacement cycle or a sudden intrusion of dry air) to significantly weaken it before landfall. While it's possible, do not count on that to happen.

The hurricane (and, by then, tropical storm) will accelerate as it pushes into the southeast, producing heavy rain and gusty winds. The chance for flash flooding and power outages from wind damage will increase from southwest to northeast as the core of the storm moves through Georgia and into the Carolinas.

Once the storm leaves the North Carolina coast on Thursday night, it will speed out to sea as it loses its tropical characteristics. The storm will bring heavy rain, gusty winds, and rough surf to parts of the Mid-Atlantic coast through the first half of Friday as it exits stage-right.

Here's what we need to watch as Michael makes landfall.


The storm is forecast to make landfall with 130 MPH winds. This will cause tornado-like damage to a wide swath of Florida's Panhandle and southwestern Georgia along the path of the hurricane's eyewall. The parts of Florida and Georgia in the path of the storm's eye are heavily forested. This hurricane will result in a significant tree blowdown, blocking roads, damaging homes, and severing power lines that could result in widespread power outages that last many days or weeks after the storm.

Hurricane Michael has a very large wind field. Tropical storm force winds (39-73 MPH) extend 300 miles across the width of the storm. Hurricane force winds extend 45 miles away from the eye. Many homes and businesses will sustain some level of wind damage, even those that are far away from the path of the eye of the storm.

The above map shows the NHC's forecast wind radii for each timestep in its 11:00 PM Tuesday forecast. You can mentally fill-in the gaps between timesteps to get a rough idea of the expected swath of hurricane force (dark red) and tropical storm force (orange) winds as Michael moves through the southeast.

For some reference on the kind of wind damage this region can see, Hermine made landfall near Tallahassee in 2016 as a minimal hurricane. Though its maximum winds at landfall were "only" 80 MPH, the storm caused considerable tree and power line damage as it pushed inland. Some residents near Tallahassee were without power for more than a week after the storm.


The shape of the coast and marshy terrain of Florida's Big Bend—the concave coast between Apalachicola and Cedar Key that bends northward—makes this part of the coast exceptionally vulnerable to a storm surge. A reasonable worst-case scenario based on the National Hurricane Center's latest forecast would push a storm surge of up to 12 feet above ground level into the Big Bend. This part of the coast is not heavily populated, but thousands of people do live in these areas, so this is a life-threatening situation.

Elsewhere along the coast, especially along and to the east of Michael's eye, a life-threatening storm surge of up to nine feet is possible. This kind of surge can easily inundate homes and businesses near the coast. The prospect of category four winds and a storm surge deep enough to submerge the first floor of homes and businesses puts those who didn't evacuate in a precarious position.


Hurricane Michael will continue moving at a decent clip once it makes landfall. This will not be a repeat of Florence or Harvey, but any flash flooding is a serious threat to life and property. A swath of rainfall possibly exceeding six inches is possible along the path of the storm from landfall on Wednesday through its exit off the North Carolina coast on Thursday evening.

The greatest rainfall totals are expected along the path of the core of the storm, but training bands of showers and thunderstorms could easily drop higher totals than those shown above. The ground is still saturated in areas that saw heavy rain from Hurricane Florence last month. It would only take a couple of inches of heavy rain in a couple of hours to trigger flash flooding in parts of the Carolinas.


As we see with any landfalling tropical cyclone, there's a risk for tornadoes on the eastern side of the storm. The forward motion of the storm combined with wind shear can allow thunderstorms in the outer bands to produce tornadoes. The tornadoes that form in tropical cyclones happen quickly and don't give people in harm's way much time to react to tornado warnings.

Why It's So Strong

Michael took advantage of very warm waters, relatively low wind shear, and ample tropical moisture to attain its current strength. The Gulf of Mexico really hasn't seen many storms this year, and that's helped this storm tap into a deep reserve of warm water and explode to its current intensity. The only two storms to enter the Gulf this year were Alberto in May and Gordon at the beginning of September. The lack of storms churning the waters, as well as persistently hot weather right up through this week, has allowed the Gulf to grow warm enough to sustain a storm as strong as Michael.

Historical Context

Past hurricanes with winds of category three or stronger that made landfall within 100 nautical miles of Hurricane Michael's forecast landfall point. | Source: NOAA

Storms this strong don't typically make landfall so far east along the Florida Panhandle. The most recent storms of this intensity to cause serious issues in the Panhandle were Hurricane Dennis in 2005 and Hurricane Ivan in 2004. Hurricane Dennis made landfall near Pensacola, while Hurricane Ivan came ashore in Alabama. The intense winds and storm surge of both storms laid waste to the western Florida Panhandle.

The last time a major hurricane made landfall within 100 nautical miles of Panama City, Hurricane Michael's forecast landfall point, was in 1894. In fact, all three major hurricanes that hit this part of the Florida Panhandle occurred in the 1800s. No hurricane with winds of category four intensity or stronger has ever made landfall along the Florida Panhandle since reliable records began in the 1800s. This storm, if it maintains its intensity through landfall, will be unlike anyone alive has ever experienced along this part of the coast.

Please take this storm seriously, even if you're hundreds of miles inland.

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October 9, 2018

Hurricane Warnings Ahead of Hurricane Michael Stretch Far Inland From the Coast

It can be deceptive to look at a hurricane forecast map if you live inland. The way watches and warnings are drawn for areas in the path of a landfalling storm can be deceptive. The National Hurricane Center's official products only show warnings as thick, colorful lines drawn onto the coast. This can lead to the perception that people who are dozens of miles away from the coast are safe. That's a worrying mistake to make. Hurricane watches and warnings can extend far inland from the coast, and that's very much the case for Hurricane Michael as it approaches the northern Gulf Coast this week.

Hurricane Michael is growing more organized as it moves through the open waters of the eastern Gulf of Mexico. The storm had 110 MPH winds at of 2:00 PM EDT Tuesday, and it's starting to look more like a formidable hurricane with each passing hour.

The latest National Hurricane Center forecast shows Michael's winds reaching category three intensity by landfall on Wednesday. Forecasters expect the hurricane to make landfall on the Florida Panhandle somewhere around Panama City, but everyone from Pensacola to Tallahassee is within the cone of uncertainty, or the margin of error in a hurricane's track based on previous years' forecast errors.

A hurricane doesn't (well, most hurricanes don't) fall apart as soon as their eye crosses the coast. The destructive winds and heavy rain can keep roaring inland, even days after a storm makes landfall. One of the biggest mistakes we can make is expecting a hurricane's ill effects to only unfold right at the coast. As we've seen from recent storms like Harvey and Florence, flooding rains can stretch far inland and lead to disaster. But a storm's strong winds can also follow a storm's path as it treks across land.

Here's what a typical array of hurricane watches and warnings look like based on mapping data provided by the National Hurricane Center. This is how you see watches and warnings depicted on the NHC's official maps, as well as most maps displayed on websites and television broadcasts:

The coastal highlights give you a good idea of which areas are under a warning, but they're deceiving for inland areas.

Here's what the watch/warning map would really look if you included all the counties under alerts:

Big difference!

More than a hundred counties from Mississippi to South Carolina are under some form of watch or warning ahead of Hurricane Michael. Hurricane warnings and tropical storm warnings extend into southwestern Georgia and southeastern Alabama, including the cities of Tallahassee, Dothan, Albany, and Valdosta. Tropical storm watches stretch as far as central South Carolina.

I understand that it's challenging to make a simple map that's also able to cram that much information into one area. The NHC's official map would be an absolute mess if it included all the counties under watches and warnings. That's one of the reasons I make my own maps for my articles. Tinkering with the data usually allows me to display more information than most other outlets, such as cities and highways and inland watches and warnings.

The simple act of issuing a hurricane warning for counties dozens of miles from the coast isn't something to take for granted. Not that long ago, some National Weather Service offices would simply issue a "wind advisory" or "high wind warning" for inland areas along the path of a landfalling tropical system. Getting rid of that kind of inconsistent messaging is one of the small changes the NWS has made in their effort to simplify the warning process and make things easier for people in harm's way to make quick and effective decisions.

(I updated this post at 2:30 PM EDT on October 9, 2018, to reflect the latest information about the hurricane.)

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October 8, 2018

Michael on Track to Hit the Northern Gulf Coast as a Hurricane on Wednesday

Tropical Storm Michael will likely become a hurricane in the Gulf of Mexico on Monday as it gradually accelerates toward the northern Gulf Coast. The storm will likely make landfall on Wednesday somewhere on the Florida Panhandle. Michael will move through quickly, but its strong winds and heavy rain could cause problems from the point of landfall in Florida northward through the Carolinas, still reeling from Florence.

The National Hurricane Center found Michael strengthening quickly on Sunday. It got its act together in a hurry, going from a disheveled tropical depression on Sunday morning to a 60 MPH tropical storm by nightfall. Michael is in a favorable environment for strengthening, and the current NHC forecast shows it doing just that between now and landfall on Wednesday evening. The storm's maximum winds could approach major hurricane strength as it nears land.

Michael could make landfall anywhere between Pensacola and Florida's Big Bend. The most likely area is in the central Florida Panhandle around Tallahassee, but the the precise forecast track will change as the experts get better data and the storm roots itself more firmly in the environment.

Tropical Storm Michael is pinned between a sharp trough over the Southwest and a strong ridge over the Mid-Atlantic. The trough/ridge combo will force Michael to take a relatively narrow path toward and over land. The storm will accelerate as the trough closes in from the west. A fast-moving storm is preferable to a slow-moving storm, since it prevents heavy rain or prolonged winds from causing more issues than they could otherwise. Even so, we're not 

Wind damage and power outages are likely around the point of landfall and for dozens—possibly hundreds—of miles inland. The current NHC forecast shows Michael still packing sustained winds of 65 MPH when it reaches eastern North Carolina on Thursday. While the storm is likely to weaken once it's over land, the potential exists for widespread wind damage along the path of the storm as it moves through the southeast.

A storm surge of several feet above ground level is likely where Michael makes landfall, especially to the east of the eye. The NHC will release more precise storm surge forecasts once watches and warnings are issued on Monday. Florida's Big Bend is exceptionally prone to storm surge. Even a weak storm hitting this part of the coast can cause significant inundation in some coastal areas. Thankfully, much of the area prone to the worst surge is unpopulated, but there are many populated areas and vacation destinations that could be affected by storm surge flooding.

The storm's swift forward motion should preclude an extreme rainfall event along its path, but the Weather Prediction Center still expects at least a couple of inches of rain along Michael's path through the southeast. Some areas could see higher totals where bands of showers and thunderstorms repeatedly move over the same spots. The ground is still water-logged in parts of the Carolinas that saw as much as three feet of rain from Hurricane Florence last month. It won't take much to trigger flash flooding in these areas.

Tornadoes are possible along the eastern part of the storm. The most likely areas to see tornadoes on Wednesday and Thursday are the eastern parts of Florida, Georgia, South Carolina, and North Carolina. Tornadoes associated with tropical cyclones can occur quickly, reducing tornado warning lead time. While these tornadoes are usually small and relatively weak, even the weakest tornado can cause life-threatening damage to buildings and vehicles.

A hurricane watch is likely for much of the Florida Panhandle on Monday. This storm is moving quickly and you don't have as much time to prepare as North Carolina did for Florence. Make sure you have the supplies to make it through a power outage and your property is properly secured from blowing debris or fallen trees.

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October 2, 2018

Four Scientists in Path of Cat 5 Hurricane Walaka As It Approaches Johnston Atoll

The U.S. Fish and Wildlife Services said on Monday that four scientists are in the path of a category five hurricane threatening Johnston Atoll, an isolated atoll in the central Pacific Ocean. Walaka is one of the strongest storms we've seen in the Northern Hemisphere this summer, and its strongest winds may come within a few dozen miles of the tiny island on Tuesday.

The latest advisory from the Central Pacific Hurricane Center pegged Hurricane Walaka's maximum sustained winds at 160 MPH, making it a category five on the Saffir-Simpson Hurricane Wind Scale. Walaka is the second such storm in the central Pacific basin this year; Hurricane Lane reached the top of the scale before approaching Hawaii in August.

Current forecasts bring Walaka's eye within a few dozen miles of Johnston Atoll on Tuesday afternoon. If the predictions hold true, the atoll would fall on the eastern edge of the eyewall, potentially subjecting it to some of the storm's strongest winds and highest storm surge. Rough waves and storm surge could easily cover much of Johnston Island, most of which lies within a few feet of sea level.

Johnston Atoll is located in the central Pacific Ocean about 800 miles southwest of Honolulu, Hawaii. Johnston Island, the atoll's largest feature, is mostly man-made, measuring about two miles long and about half a mile wide. The island consists almost entirely of a runway and various (largely abandoned) government installations.

Johnston Island played a role in the development of the United States' nuclear arsenal. Numerous nuclear tests were conducted there during the height of the Cold War, and Johnston Atoll was heavily contaminated by radiation after the failure of Bluegill Prime on July 25, 1962. The island's population peaked around the turn of the millennium during the effort to rid the island of pollution from both radiation and Agent Orange, large containers of which were stored there after the Vietnam War.

While Johnston Atoll lacks a permanent human population, the U.S. Fish and Wildlife Service told me late Monday night that there are four members of the U.S. Fish and Wildlife Service's biology field crew currently working on the island. A spokesperson for the agency added in an email:

In preparation for any possible impacts from Hurricane Walaka, the field biology crew secured the year-round field camp. We are working with the U.S. Coast Guard to evacuate the four field crew members on Johnston Island, if weather and circumstances allow. Currently, on island staff are sheltering in place at a steel and concrete structure built to withstand hurricanes.

We are continuing to monitor Hurricane Walaka as it moves through the Pacific and will stay in close coordination with the U.S. Coast Guard as the situation evolves.

The spokesperson added that herbicides, insecticides, and propane tanks were secured before the staff took shelter.

The structure referenced by the agency, pictured in the red box in the Google Earth snapshot above, lies on the northeastern side of the island. Walaka (and its strongest winds/surge) are approaching the island from the south. This may somewhat blunt the effect of storm surge flooding if the crew can't evacuate.

A hurricane watch is in effect for the Papahanaumokuakea Marine National Monument, the long chain of tiny islands and atolls that extend for a thousand miles northwest of the main Hawaiian Islands. The center of the storm is not likely to affect any of the northwestern Hawaiian Islands with the capability of supporting a research population.

The storm will not affect the seven populated islands of Hawaii, though rough surf and rip currents are possible along south-facing shores as the storm passes far to the state's west.

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September 27, 2018

This Has Been One of the Eastern U.S.'s Muggiest Years on Record

This has been a miserable year in more ways than one. If it seems like the weather was especially stifling in the eastern United States this summer, now you have hard data to back up your months of complaining on Facebook. This has been one of the muggiest years on record in the eastern part of the country. Record warmth is one thing—we can sort of deal with the heat—but humidity is a clingy misery you just can't shake, and it was in deep supply this summer.

While relative humidity is a classic way to measure the amount of moisture in the air, it doesn't really tell us much since it's relative to the air temperature. Relative humidity goes down with the heat of the day and rises as the air cools off at night.

A better way to objectively measure how comfortable the humidity feels is to use the dew point, or the temperature at which the air would reach full saturation, or 100% relative humidity. Dew points below 60°F are generally considered comfortable. It's noticeably humid when the dew point reaches 65°F, putrid when it reaches 70°F, and unbearably muggy when the dew point climbs into the mid or upper 70s. The summertime dew point in Miami routinely reaches or exceeds 75°F.

So far this year, a number of major cities in the eastern United States have seen the most hours they've ever recorded with a dew point at or above 70°F. Cities that have seen their muggiest years on record stretch from Alabama to Massachusetts, including Montgomery, Charlotte, Washington-Dulles Airport, Scranton, Providence, and Boston.

Some cities have seen more than a thousand hours of dew points at or above putrid levels in 2018. Records at New York's JFK Airport stretch back to 1948. The previous record-high number of hours at or above 70°F was about 850 hours set in 1984. This year, the airport has recorded more than 1,200 hours with dew points at or above 70°F. It's a similar story at the airport in Charleston, West Virginia, where the previous record of around 850 hours set back in 1949 was eclipsed by this year's count of nearly 1,200 hours of putrid humidity.

A series of stubborn centers of high pressure were the driving forces behind this year's rancid summer. If you look back through my blog posts over the past couple of months—especially before the hurricanes—I sounded like a broken record talking about stifling humidity and the chance for flash flooding due to strong thunderstorms. (See also: "Oh, For Crying Out Loud, Please Not This Gross Weather Pattern Again.")
The GFS model's precipitable water forecast on the afternoon of July 31, 2018. | Source: Tropical Tidbits

The East Coast found itself stuck under the western side of a strong ridge of high pressure parked over the western Atlantic Ocean. This persistent southerly flow opened the conveyor belt for tropical air to flow north over the eastern part of the country for months on end. Not only has it been uncomfortable since the end of spring, but the relentless, excess moisture allowed thunderstorms to turn into water factories, leading to numerous flash flood emergencies across this region of the country.

(PS: I compiled this data using the Iowa Environmental Mesonet's awesome observation archives and their nifty tool that lets you plot the number of hours a station has seen a certain temperature or dew point over certain a period of time. If you're ever in a bar fight about how many hours the temperature in Buffalo was below zero in 2004, the IEM's got you covered.)

(PPS: The answer is 40 hours.)

[Top Image via Flickr user kandypics]

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September 24, 2018

Severe Thunderstorms Are Possible in the Northern U.S. This Week

Pumpkin spice, cooler air, and angry election ads proclaiming the end of the world—it sure feels like fall, but the weather doesn't always agree. A potent cold front will sweep across the northern United States and southern Canada through the middle of the week, potentially triggering severe thunderstorms along its path.

The Storm Prediction Center's forecasts on Monday showed a slight risk for severe thunderstorms in the Great Lakes and Midwest during the day on Tuesday, with the severe threat moving into the Northeast on Wednesday. The maps stop at the border—there are sovereignty and tax-dollar issues preventing most government weather maps from extending into Canada—but you can use your imagination to fill in the missing lines that extend into southern parts of Ontario and Quebec.

The pattern is a classic fall severe weather setup. A strengthening low-pressure system will cross the Great Lakes into eastern Canada over the next couple of days, dragging down cooler and less-humid air behind it. The cold front, digging into warm-ish and muggy-ish air to the south, will trigger lines of severe thunderstorms, some of which could be severe with damaging wind gusts, large hail, and isolated tornadoes.

The SPC mentioned in its afternoon update on Monday that the risk in some areas on Tuesday could be upgraded to an enhanced risk—a three out of five on the scale measuring the severe weather risk—if it looks like some storms could tap into enhanced instability and wind shear.

Even though the threat for severe storms isn't as high as you would see in the spring, any risk for severe thunderstorms is a big deal if you're in the path of one. It's worth paying attention to watches and warnings this week, particularly since folks don't normally expect severe thunderstorms now that we've been able to wear our coats a few times, and since there are lots of outdoor events now that schools are back in session.

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September 17, 2018

Trump Isn't 'Taking Over' Your Cell Phone and This Conspiracy Theory Could Kill You One Day

Warning people about dangerous weather is a matter of life or death. Meteorologists need all the help they can get when it's time to get the word out about severe weather. The federal government is about to test one of those important warning systems in a few weeks. As we approach the test on October 3, I have one thing to say: Y'all are out of your got-danged, ever-lovin', conspiracy-addled minds if you think Donald J. Trump is planning to take your cell phone to make you read his angry rants while he watches television. Seriously? Come on now! Get a grip.

Stealing a page from Alex Jones' Little Black Book of Big Black Helicopters, the #resist side of Twitter has firmly latched on to the news that FEMA will conduct a nationwide test of the Emergency Alert System on Wednesday, October 3 as proof that Donald Trump is planning take over everyone's cell phones on command. The unbelievable hyperventilation over the test—which was also pushed about Obama by the Alex Joneses of the world seven years ago—came about thanks to several news sites and big-name viral Tweeters screaming misleading headlines at their millions of readers. Even Time's article on the tests opened with the line "you may be getting text messages from President Donald Trump soon."

Emergency Alerts Can Save Your Life

An example of what a Wireless Emergency Alert looks like on an Android smartphone.
Here's what's going on. FEMA will conduct a nationwide test of the Emergency Alert System on Wednesday, October 3. (The test was originally scheduled for September 20, but was rescheduled due to Hurricane Florence.) The test will be pushed to cell phones at 2:18 PM EDT and transmitted to television and radio stations at 2:20 PM EDT. The federal government has conducted these nationwide EAS tests a couple of times in recent years—to varying degrees of success—but this will be the first time that the test includes the Wireless Emergency Alert capability on cell phones.

Starting in 2012, all modern smartphones gained the ability to receive Wireless Emergency Alerts. These alerts are sent to your device based on your location. If you're within an alert—say, a tornado warning—you'll instantly see a push notification on your device that's accompanied by a loud, EAS-like tone. These WEAs are proven life-savers, transmitting alerts like tornado warnings to people who might not otherwise have been paying attention to the weather.

That's all it is. Really.

Wireless Emergency Alerts on your smartphone can save your life. The system has only been in place for a couple of years, but there are documented cases of people saving their lives by acting on alerts sent to their phone just minutes before their homes were destroyed in a tornado or flood.

The catch is that you can't disable presidential alerts. Those are the only alerts you can't shut off. You can shut off tests, severe weather alerts, and AMBER Alerts, however, which is what I fear many people will do if they're afraid "the president is taking over their cell phone." Do not shut off the weather alerts on your phone to spite the president. Tampering with your weather alert settings does nothing to stop the presidential alerts and could jeopardize your safety one day.

Presidential Alerts Are A Relic of the Cold War

It's easy to forget that the Emergency Alert System exists for reasons other than giving you chills. The EAS is the successor to the Emergency Broadcast System and CONELRAD, systems developed to allow the president to quickly address Americans in the event of a nuclear war or invasion. Due to the relative lack of nuclear wars or foreign invasions in the decades since the alert systems were developed, the ever-present feature on television and radio is mostly used to transmit severe weather warnings and child abduction alerts.

Every president since Harry S. Truman has had the ability to activate the EAS (or its predecessors) and quickly address Americans in the event of an emergency. The presidential purpose of the EAS didn't become widespread knowledge until FEMA conducted its first nationwide test of the system on November 9, 2011.

That test was pretty glitchy. Some stations never repeated the alert. Some never shut the alert off. Folks watching DirecTV heard pop music during the test. But finding those glitches was the whole point of the test. They've repeated that nationwide test a couple of times in recent years, but this will be the first to include test alerts on cell phones as well.

The Same Conspiracies Were Pushed About Obama

Similar conspiracy theories ran wild in the lead-up to the 2011 test, but from the other side of the spectrum. Alex Jones' site, InfoWars, ran news of the test with the headline "OBAMA LAUNCHES TOTAL TAKEOVER OF MEDIA SYSTEM."

Here's how they freaked out about it at the time:

Even the Washington Post describes it like something out of Orwell’s 1984. The FCC has approved a presidential alert system. Obama may soon appear on your television or call your cell phone to warn you about the next specious al-Qaeda underwear bombing event.


Once again, the government has imposed an unreasonable and absurd mandate on business and the American people

Sound familiar? Right-wing blogs and commentators, ever-wary of the government's power and seething with rage over Obama's presidency, latched on to these nationwide television and radio alerts as evidence that the president was going to use the system to take over the airwaves and indoctrinate Americans with propaganda.

That didn't happen, of course. No president has ever used the Emergency Alert System (or its predecessors) to address the country. The government didn't even use the system on September 11, 2001, as the events of the day were immediately carried live on every television network in the country.

The system is there, though, just in case they need to use it one day. You can argue that the central premise of the Emergency Alert System is less necessary today than it was back in the days when television and radio were our only means of instant mass communication. If North Korea launched a nuclear missile at the United States, we're likely going to hear about it before Trump or anyone in Washington can go through the steps of activating the EAS.

It's improbable that even the most attention-craving president would abuse the slow, bureaucratic process it takes to activate the Emergency Alert System as their own personal megaphone. It doesn't take long for a Trump tweet to make its rounds. A screenshot of every tweet is blasted on cable news within a minute of its issuance.

This system isn't there to let Trump send you text messages while he angrily watches Fox News. The system is there to warn you in case of a missile launch, foreign invasion, or natural disaster. You'll probably only ever see these alerts before tornadoes and flash floods. Please don't disable these alerts on your cell phone because of what you read online. The alerts could save your life one day.

*This post was corrected to reflect that the test was postponed from September 20 to October 3 due to the lingering effects of Hurricane Florence.

[CONELRAD advertisement via Wikimedia Commons]

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September 13, 2018

Hurricane Florence Is a Slow-Motion Disaster With Historic Rains, Deadly Storm Surge

Hurricane Florence is making a slow-motion landfall along the North Carolina coast this evening. The storm is moving painfully slow—just 5 MPH as of 11:00 PM Thursday. The storm's creeping track toward North Carolina and South Carolina will expose a vast swath of land to an extended period of intense winds, historic rains, and exacerbate the life-threatening storm surge already inundating the coast.

The National Hurricane Center expects Florence to eventually make landfall near Wilmington, North Carolina, during the day on Friday. It will begin pushing inland through the weekend before a trough picks it up and causes it to race toward the Northeast early next week.

Hurricane Florence is going to be a long-duration event, and we can't stress the hazard posed by water with this storm. Most fatalities in a landfalling tropical cyclone are caused by drowning. Freshwater flooding from prolonged heavy rain and a storm surge at the coast will likely cause damage from this hurricane to rise into the billions of dollars. This was a well-warned event, and hopefully most folks in the path of flooding and surge were able to get out before the storm made escape all but impossible.


The latest forecast from NOAA's Weather Prediction Center shows an eye-popping swath of 20"+ of rain expected by the end of the storm. This would exceed the devastating rainfall totals seen in 1999's Hurricane Floyd and the remnants of Hurricane Matthew in 2016. This kind of rain will lead to unprecedented flooding in this part of the Carolinas. I've never seen a rainfall map like this before outside of Texas during Hurricane Harvey last year.

Adding insult to injury, the WPC notes that some areas in that 20"+ swath may see final totals up near 40". That's more than three feet of rain. That would make this the wettest tropical cyclone in the southeastern United States and one of the wettest in the country's history. Rainfall will taper off—a relative term, in this case—farther inland, but totals of 6-12 inches (higher in some spots) will still lead to flash flooding as far inland and north as the Virginia mountains.

Forecasts of excessive rain are already verifying where Florence's rain shield is ashore. A rain gauge near Morehead City has reported a foot of rain since the storm started earlier on Thursday. Given the storm's slow movement, that total will easily double by this time tomorrow.


Expected storm surge from Hurricane Florence. SOURCE: National Hurricane Center
It's not just the rain causing life-threatening flooding. A storm surge of 10 feet above normal water levels was reported at the Cherry Branch Ferry Terminal, located near the mouth of the Neuse River southeast of New Bern, North Carolina. The storm surge along the coast in North Carolina is enough to inundate the first level of homes and businesses near the shore. This will kill people who elected to stay behind and can't evacuate to a higher level or the roof.

The surge will continue to build along north- and east-facing coasts as the storm nears landfall. This was one of the problems with focusing on Florence's maximum wind speeds. As I wrote yesterday, the storm started translating its energy into expanding the wind field rather than focusing it all in an intense sting of winds in the eyewall. Large, strong storms lead to devastating storm surges. We've seen it time and time again in past storms, and it's playing out right now in Florence.


While flooding is the headline story from this hurricane, the wind can't be ignored. Winds are already gusting around 100 MPH as the core of the storm starts dragging over land. A 105 MPH wind gust was reported at Fort Macon, N.C., just after 8:00 PM on Thursday. Between 9:00 PM and 10:30 PM, Fort Macon saw another gust up to 99 MPH, a 96 MPH gust occurred at Cape Lookout, and the NWS office in Newport, N.C., saw an 82 MPH gust.

The wind is already causing severe and widespread power outages. This trend will continue down the coast and inland as the ground softens due to heavy rain and flooding. Millions of people will spend a long time in the dark because of this storm. Downed trees will also likely block roadways, damage homes, and potentially crush cars.

There's some discussion about how folks in harm's way reacted to the storm "only" packing category two winds as it approaches land. Even without the extreme winds, the biggest story with Florence was always going to be the water. The categories of the Saffir-Simpson Scale only apply to winds. It says nothing of the storm surge or rain that accompanies the storm. Many of the most destructive storms we've seen in the past couple of decades packed hazards far greater than their category.

Even so, it's easy to lose sight of how much wind damage can be caused by a low-end hurricane. Severe thunderstorms are warned for 60 MPH wind gusts and many of the memorable derechos of years past had maximum winds of 80 to 90 MPH. Those winds only lasted for a few minutes. These are lasting for many hours without relenting.

Hurricane Florence Set to Bring Intense Flooding and Storm Surge to Carolinas

Don't let the headlines proclaiming that "Hurricane Florence has weakened" fool you. It's still an intense storm tonight as it lumbers toward the Carolinas. Florence's winds have dropped below major hurricane status as the storm struggles against wind shear and turmoil within its own structure. While the winds aren't as ferocious as they once were, Florence is still a large and dangerous storm. Coastal communities will likely suffer a life-threatening storm surge as sustained winds of 100 MPH or more batter the coast for hours on end. After landfall, many areas even hundreds of miles from the coast will be exposed to the threat for flash flooding from potentially-historic amounts of rain.

Hurricane Florence had 110 MPH winds as of Wednesday's 11:00 PM EDT advisory. Florence is much more ragged looking tonight than it was on Tuesday. The eye is poorly defined and the eyewall is struggling to stay closed due to westerly wind shear disrupting the storm's structure. Even so, Florence is expected to remain a strong storm through landfall.

RELATED: You Should Prepare for Hurricane Florence Even Hundreds of Miles Inland 

It's not terribly uncommon for a storm like Florence to see its winds start to weaken at this stage in its life cycle. First of all, it's hard for scale-topping storms to survive this far outside of the tropics. That's why it was such an eye-popping prospect that Florence could have been the farthest north such a strong storm has made landfall on record in the United States.

The other reason Florence's maximum winds were prone to falling is the storm's natural structure. A tropical cyclone's winds are generated by the extreme pressure gradient between the core of the storm and the environment around it. Weather is nature trying to balance itself out—the intense winds exist because air is rushing in to fill the void at the center of the storm. This usually leads to a tight core of strong winds in the right-front quadrant of the eyewall.

Sometimes, though, a hurricane can translate its deep air pressure into widening the wind field rather than packing all that energy into a tiny part of the eyewall, and that—along with disruption from wind shear—appears to be what's happening with Hurricane Florence. The hurricane is using its strength to bulk-up rather than sting one particular area.

This storm has a very large wind field. The wind swath map above shows how the footprint of Florence's winds has grown since it strengthened back into a hurricane last week. I hate using this as an example because it may give anyone speed-reading the wrong idea, but the "deep pressure widening the wind field" scenario is one of the reasons Sandy touched such an enormous area of the East Coast. The storm had the minimum pressure of a major hurricane, but only had maximum winds of 80 MPH at landfall—the storm's wind field at landfall, however, measured about 1,000 miles across. (For comparison, Florence's wind field measures more than 350 miles across.)

Models seem to have neatly converged on a nightmarish scenario for the southern N.C. and northern S.C. coasts. The storm is now expected slow to a crawl near the coast or just after crossing the shore, subjecting areas to the north of the eye to a prolonged period of destructive winds, storm surge, and potentially-historic amounts of rain. In addition to the damage caused by hours of winds in excess of 100 MPH, the storm surge could exceed nine feet above ground level in the worst-hit areas, completely inundating and likely destroying buildings near the coast.

Once the storm moves inland, meteorologists now expect the center of the storm to dip into South Carolina through the weekend jutting north into the Ohio Valley on Monday. The storm is so large that the exact track of the center of the system only matters in determining who will see the heaviest rain, strongest winds, and the greatest chance for tornadoes through early next week.

The rain will be Florence's lasting legacy. There's a chance that some communities are about to have the wettest couple of days they've ever recorded. Unprecedented amounts of rain will lead to widespread flooding, even in areas that don't typically flood. The flooding threat will stretch hundreds of miles inland. Flash flooding is likely near the track of the storm and landslides/mudslides are possible in the mountains as the storm and its remnants move through the area.

This afternoon's forecast from the Weather Prediction Center showed the chance for more than 20 inches of rain near the coast. Some areas could see more than three feet of rain by the time the storm is over. This could easily be one of the wettest tropical cyclones ever seen in this part of the United States. Rainfall totals of up to a foot are possible inland through parts of North Carolina and South Carolina.

We also can't ignore the risk for tornadoes. Tornadoes are always a possibility in the right-front quadrant of a landfalling storm—in this case, to the north of the storm's expected track. Tornadoes that occur in landfalling tropical storms are usually weak and don't last very long, but they can happen quickly. The tornado warning lead time can be reduced to just a few minutes in a situation like this.

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September 11, 2018

The Case for Preparing for Hurricane Florence Even If You're Hundreds of Miles Inland

Hurricane warnings are in effect for the North Carolina and South Carolina coasts ahead of Hurricane Florence, a powerful category four storm that's expected to make landfall on Friday. The hurricane will slow to a crawl near the coast, producing historic rainfall totals that will likely lead to catastrophic flooding across parts of North Carolina, South Carolina, and Virginia.

If you've followed my writing for a while, you know that I'm averse to hype. Hyping up "normal" bad weather sucks because it takes the punch out of truly disastrous storms. It's the Crying Wolf Effect in action. This is not one of those storms. If the current forecasts pan out, Hurricane Florence is on track to become a generational storm in North Carolina. This could be the storm to which all future storms are compared for decades to come, much like Hurricane Hazel in 1954 or Hurricane Floyd in 1999.

Sustained winds greater than 100 MPH and a destructive storm surge exceeding nine feet above ground level in spots would lead to widespread damage in coastal communities where the center of the storm makes landfall. The storm's size would allow damaging winds and a life-threatening storm surge to extend far up and down the coast from the point of landfall. This will be a large storm when it approaches land and its size will bring hazardous conditions to an area hundreds of miles wide.

This hurricane won't only be a coastal disaster. Florence's flooding rain and wind could extend far inland away from the coast. Flooding is possible hundreds of miles away from where the hurricane makes landfall. You need to prepare for the wind and rain from the storm even if you live as far inland as the mountains.

The water section at my Walmart was mostly wiped out by 3:00 PM Monday.

I do not live on the coast. I do not live anywhere near the coast. It would be an all-day production to drive from where I live to the coast. But I've spent the past two days in and out of grocery stores getting ready for Hurricane Florence. We make a mistake when we think of hurricanes as purely a nuisance for people who built their homes 100 feet from the water. Hurricanes—and this hurricane in particular—won't begin to unleash its full potential until the storm is inland.

But while we always focus on the point of landfall (for good reason!), it's just the beginning of Florence's story. I wrote an article for Popular Science  on Monday detailing why Hurricane Florence could be such a big deal for inland areas far beyond the coast:
Weather models generally agree that the storm is likely to make landfall in North Carolina during the day on Thursday. The storm is also likely to slow to a crawl once it moves inland. The hurricane is moving into the bottom of a strong ridge of high pressure over the eastern United States and Canada. Ridges usually foster calm weather, but that calm environment will force Florence to sit and spin over the same areas for days on end. Without any other weather systems to push Florence along, some models don’t see Florence moving out of the region until early next week.
In fact, you'd be forgiven for thinking you've seen this entire storm before and this is some protracted fever dream. We went through a slightly similar event last year with Hurricane Harvey. That hurricane made landfall as a category four, stalled out over land, and dumped historic amounts of rain over coastal parts of Texas and Louisiana.

The amount of rain that could fall in Hurricane Florence may be unlike anything recorded from a tropical cyclone in this part of the country. Our country's recent history with horrendous flash flooding caused by landfalling tropical systems should inform the actions of anyone in the Carolinas and Mid-Atlantic this week. If forecasts hold true, Florence looks likely to break the record for most rain ever produced by a tropical cyclone in North Carolina, a spot currently held by the two feet of rain dropped during Hurricane Floyd.

The heaviest rain and strongest winds will be determined by the exact track of the hurricane. But don't just focus on a couple of points on a map. The NHC's track forecasts—like the one at the top of this post—only apply to the center of the storm. The heavy rain, wind, and storm surge can extend hundreds of miles from the center of the storm, and that will certainly be the case with Florence.

Not only that, but the center of a storm historically stays within the cone of uncertainty 66% of the time. The average error for NHC track forecasts is more than 100 miles after 4 or 5 days.  The window of possible tracks for this hurricane could take it anywhere from South Carolina to the Virginia Tidewater.

The meteorologists at the NHC are experts in their field, and they use their experience with the preponderance of evidence to come up with their forecasts. They believe that their current forecast is the most likely scenario based on the evidence before them. Models will refine their guidance and meteorologists will improve their forecasts as we get closer to landfall on Friday.

Monday afternoon's rainfall forecast from NOAA'S Weather Prediction Center.

According to current forecasts, intense rainfall is likely along coastal regions of North Carolina. Wilmington, N.C., could see several feet of rain by the end of the weekend if the storm does indeed make landfall there. Flooding rain is most likely in eastern and central parts of North Carolina, South Carolina, and Virginia.

The bullseye for the heaviest rain will keep moving around as forecasters refine their track predictions as we draw closer to landfall and they can figure out how the storm is going to meander once it gets near or over land.

Inland flash flooding is the silent killer in storms like this. Many people believe that they're safe from a hurricane's ill effects because they're nowhere near the coast. That wasn't the case in Louisiana in 2016, Texas in 2017, and it won't be the case this week with Florence.

Some communities may set all-time rainfall records. The record for the most rain ever recorded in a three-day period in Roanoke, VA, is 8.99" set in 1987. That record was 6.99" in Danville, VA, set in 2008. The most rain recorded at Raleigh-Durham Airport in a three-day stretch was 10.05", and 19.66" is the top three-day total in Wilmington, N.C. Unfortunately, all of those records could be broken this weekend.

If you live inland, please do not ignore this storm. Areas that don't typically flood—and areas outside of designated flood zones—may flood with unprecedented rainfall. Incredibly heavy rain can easily wash out roads and cut off your routes around town. Water that looks shallow may not be. Even if you're unaffected at home, your ability to get around town may be severely hampered or impossible due to flooded roadways.

There's also the issue of power outages. I drive home this point a lot because the power grids in my county—and in many rural areas—are fragile. We lose power during an obnoxious summertime thunderstorm. The potential for sustained winds of 20-40 MPH (with higher gusts) reaching far inland, along with rain-soaked ground, could easily bring down trees and power lines. Power companies will have a hard time keeping up with all of the power outages. It may take longer than normal for crews to restore power to your neighborhood.

FOOD: I say it over and over again, but you don't realize how much you use electricity until you really need it. How much food do you have in your house that you can eat without having to cook it or keep it cold? Would you be able to feed yourself and your family for several days without cooking, refrigeration, or getting food from a restaurant? We laugh at people for rushing to the store to stock up before a snowstorm, but it really is necessary under threat from a hurricane.

WATER: Stocking up on water—bottled or stored from the tap—is important. You've got pretty good odds of the water staying on even if the power goes out. But if you're in an area that experiences an exceptional power outage or bad flooding, municipal pumping stations or treatment plants may be compromised. Under normal circumstances, officials would issue a boil water advisory and you'd be fine, but it's usually impossible to boil water at home during a storm when you have no electricity.

LIGHTS: Batteries and flashlights are another important but overlooked supply. Many folks probably use the flashlight feature on their cell phone these days and may not have an actual flashlight in their house. If the power goes out, you'll need to conserve every precious bit of battery you've got in your cell phone. "Power Outage Dark" is one of the darkest darks you'll experience outside of camping in the wilderness or sailing with the lights off. The moon's phase during the hurricane will be a waxing crescent—not much help to those without power, and even less so with thick clouds overhead.

CELL PHONE: Think about your cell phone, too. A portable battery pack is a good investment to make. Most are good for at least one full charge of your cell phone, if not more. You can also charge your cell phone in the car, but you run the risk of wasting precious gas or draining your car's battery. If you have no way to charge your phone in a power outage, shut it off and use it with your battery saving settings turned to max. (Some phones also have an "emergency" setting that disables almost all features to conserve battery life.)

MEDS/CASH/ETC.: Think about all the other things you'd need if the power goes out or you're cut off from getting around town for several days. Do you have enough prescription meds to get you through to next week? How about toilet paper? It's a cliché that goes without saying, but fill up your gas tank. After all, gas stations will likely shut down without power. That brings up another issue—if the power goes out, your credit/debit card does you no good. If you can afford to have some cash on hand, it'll help if you need to buy things and retailers around town are open and cash-only.

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