August 3, 2020

Hurricane Isaias Makes Landfall In N.C., Strong Winds Likely Up I-95 Next Two Days

After several days of changing its appearance more than a theater star—yet maintaining its intensity against the odds—Isaias made landfall at 11:10 PM EDT near Ocean Isle Beach, North Carolina with 85 MPH winds. The system will push into eastern North Carolina overnight into Tuesday as it picks up speed and races up the Interstate 95 corridor. Widespread power outages and flash flooding are possible along the path of the storm as it heads toward Maine.

Show someone a satellite image of the hurricane making landfall in North Carolina and almost no one would guess that this thing has a solid core producing sustained winds of 85 MPH:

This has been quite the storm to follow over the last week. Hurricane Isaias organized its inner core and began to strengthen just as the eyewall began scraping the South Carolina coast. It seems counterintuitive, but we're pretty fortunate that strengthening happened now as opposed to a couple of hours ago; the hurricane could've strengthened more if it had more room to gobble up instability over the open water. A team of Hurricane Hunters found 85 MPH winds on the eastern side of the eye (with flight-level winds of  100+ MPH!), which isn't great news for coastal North Carolina, which will experience those hurricane force winds for several hours tonight.

As I explained in last night's post, the system will begin drawing some of its energy from the jet stream as it accelerates northward up the East Coast. This process is known as extratropical transition, resulting in a system that'll more closely resemble a strong nor'easter than a hurricane by the time it reaches New England on Tuesday night. This transition will allow Isaias to grow in size, exposing a larger area to strong winds and heavy rain.


Isaias will make 'official' landfall—the center of the eye crossing the coastline—near Shalotte, North Carolina, around midnight, with sustained winds of about 85 MPH. The National Hurricane Center's forecast shows Isaias following a straight shot up the coast, reaching the Delmarva by Tuesday morning, New York City by Tuesday evening, and moving through Maine into the Canadian Maritimes on Wednesday.

Hurricane warnings are in effect for the counties where the storm is making landfall. Tropical storm warnings are in effect for the entire coast from Charleston, South Carolina, through southern Maine, including many inland areas where folks wouldn't necessarily expect to witness tropical storm conditions. Anyone in the tropical storm warning can expect a period of sustained winds of 35+ MPH, as well as the potential for flash flooding from heavy rain.

Wind & Storm Surge

The hurricane isn't going to wind down immediately once it comes ashore. The momentum of the storm and the influence of the jet stream will allow it to gradually lose strength, exposing lots of densely populated communities to a period of strong winds and even higher gusts.

Widespread power outages are likely from the point of landfall and northward through the New York City metro area, with scattered power outages possible elsewhere. For what it's worth, the NHC's evening forecast shows Isaias making it to New York City with sustained winds of 65 MPH with higher gusts. You can only hope folks in this region appreciate how strong the winds will be and how much damage those winds can do to the trees and power lines in these areas.

Storm surge is an issue since the storm will track so close to the coast. Onshore winds will push a surge of seawater into coastal communities. It won't be a big surge—a few feet deep in the hardest-hit communities—but even a few feet is dangerous if it swamps an occupied vehicle or it swamps a one-floor house or a condo complex. The NHC's map of potential storm surges is above.


Flash flooding is likely across areas in Isaias' path over the next couple of days. The Weather Prediction Center shows 3 to 5 inches of rain falling along and to the west of the center of the storm, which includes communities along and west of Interstate 95. The greatest rainfall totals are possible on the eastern side of the D.C. and Baltimore metro areas during the day on Tuesday.


Tornadoes are an ongoing threat as the storm moves ashore. Tornado watches are in effect for almost all of eastern North Carolina tonight as Isaias makes landfall, and the threat will follow the eastern part of the storm as it moves up the coast. Multiple tornadoes have already occurred around Wilmington, and the supercells that produced them are hauling tail at highway speeds.

Here's the SPC's severe thunderstorm outlook for the rest of the night through 7:00 AM EDT on Tuesday...

...and here's their severe thunderstorm outlook for the day Tuesday and into early Wednesday morning:

Tropical tornadoes happen quickly and that speed reduces tornado warning lead time. Stay alert and make sure you've got a way to receive warnings the instant they're issued. Modern smartphones are equipped with emergency alerts that can be activated through the notifications section of your phone's settings.

[Radar: Gibson Ridge | Satellite: NOAA]

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August 2, 2020

Isaias Flirts With Hurricane Strength; Monday Night Landfall In Carolinas Likely

Tropical Storm Isaias keeps fighting back against the atmospheric forces trying to tear it apart, managing to maintain its strength on Sunday as it paralleled Florida's east coast. Forecasters expect the storm to flirt with hurricane strength as it accelerates toward landfall in the Carolinas overnight Monday and into Tuesday. Isaias has the potential to be a disruptive storm as it traverses the U.S. East Coast and brings dangerous wind gusts and flooding rain to densely populated areas.

The track forecast for Tropical Storm Isaias hasn't changed much in the last few days. That kind of consistency is a good thing since it's given folks in harm's way ample opportunity to prepare for the potential for gusty winds, heavy rain, and power outages. The latest forecast from the National Hurricane Center shows the storm picking up speed over the next 24 hours as it approaches the Carolinas. Landfall is likely on Monday night around Myrtle Beach, S.C., or Wilmington, N.C.

Accordingly, tropical storm watches and warnings are in effect for a large swath from central Florida to southern Connecticut. A hurricane watch is in effect from South Santee River, S.C., to Surf City, N.C., just in case Isaias strengthens back into a hurricane. The map above shows all the county-based alerts in effect as of 11:00 PM on Sunday. The difference between a 70 MPH tropical storm and a 75 MPH hurricane is negligible, so the folks near the point of landfall can expect a period of damaging winds regardless of whether Isaias makes it back over that threshold or not.
Source: NOAA

Tropical Storm Isaias looks pretty healthy tonight. It's got strong thunderstorm activity bubbling near the center of circulation. There's intense transverse banding in the outflow on the northern edge of the storm; this scalloped ridging is the result of turbulence and it's common around healthy storms with robust convection that's venting lots of air into the upper atmosphere.

Isaias is going to start losing some of its pure tropical-ness pretty soon. So far, the storm's been influenced by two major features around it: a strong Bermuda High to its east that's kept it from running back out to sea, and an upper-level trough over the Mississippi Valley that's kept it from heading west into the Gulf. These two features combined are responsible for its very careful curve from the Caribbean into the Carolinas. 

Isaias has been lopsided ever since it crossed Andros Island in The Bahamas. That's why it was mostly just breezy and showery on Florida's East Coast on Sunday even though the center of the storm is so close to shore that a daredevil could intercept it with a kayak.
Source: Tropical Tidbits

However, the tropical storm is going to start to 'feel' that upper-level trough come Monday, deriving some of its energy and influence from the jet stream like a Nor'easter would. This will allow the storm to grow in size and accelerate up the coast.

Once it begins to grow and its structure changes a bit, the heavy rain and winds will start wrapping around and filling in the western side of the storm. This is why the forecast looks so much rougher in Wilmington than things look in Cape Canaveral right now, even though the center of the tropical storm is just a few dozen miles offshore of NASA's launch pads.

Wind & Storm Surge

Source: NHC

The strongest winds and heaviest rains will follow the core of Isaias as it moves inland on Monday night and Tuesday. Myrtle Beach and Wilmington will take the brunt of the storm; these areas could see a period of hurricane force winds and more than half a foot of rain. Widespread power outages are likely in areas that see strong winds. Keep your cell phones charged and your flashlights close by on Monday night.

Strong winds will continue into the Mid-Atlantic and Northeast on Tuesday and Wednesday. Tropical storm conditions (sustained winds of 40+ MPH) are possible as far west as Washington D.C. and Philadelphia. The latest NHC forecast calls for the storm to have maximum sustained winds of 45 MPH when it moves over New York City on Tuesday evening. 

Even a strong tropical storm can lead to a storm surge along the coast, especially where the storm makes landfall. A storm surge of 2 to 4 feet above normal tide levels is possible between Edisto Beach, S.C., and Cape Fear, N.C. That doesn't sound like much, but it's life-threatening for homes along the coast that are susceptible to storm surge flooding, made even worse by the fact that rescue crews may not be able to reach homes inundated by flooding until after the worst of the storm has receded.

Heavy Rain & Flash Flooding

Flash flooding is likely along the Isaias' track as it moves up the coast. The heaviest rain is likely in the Carolinas and Mid-Atlantic; the Weather Prediction Center calls for widespread totals of 3-5 inches from the point of landfall through New England, with higher totals likely in some locations if they get caught under a particularly heavy band.

Flooding from heavy rain is the leading cause of death in a landfalling tropical cyclone. It only takes a few inches of moving water to lift a vehicle and carry it downstream. It's impossible to judge how deep the water is until it's too late, and sometimes the road is even washed away under the moving floodwater.


Tornadoes are always a threat when a tropical cyclone makes landfall. There's enough low-level wind shear in these systems to spawn quick tornadoes, especially along and to the east of the storm's forward motion. Right now, the greatest threat for tornadoes exists across eastern North Carolina on Monday night and Tuesday, where the Storm Prediction Center has issued a slight risk for severe weather.

Tropical tornadoes sometimes occur so quickly that the normal tornado warning lead time is reduced to just a few minutes at most. Stay close to safe shelter if you're near the path of the storm, and make sure the emergency alerts are activated on your smartphone. (The option is usually under the settings for notifications.)

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August 1, 2020

Hurricane Warnings Continue For Florida As Struggling Isaias Approaches Land

Hurricane warnings remain in effect for much of eastern Florida this afternoon as Tropical Storm Isaias begins to move away from The Bahamas. The storm is struggling against a stream of dry air and wind shear trying to tear its convection apart, but it wouldn't take much reorganization to regain some of its strength. Florida will begin feeling the effects of the storm tonight into Monday before the system accelerates up the East Coast through the middle of the week.

Isaias is a resilient storm. The storm lost some of its strength and organization on Saturday as dry air and wind shear chomped away at its structure. The "eye" of the storm was fully exposed at one point, shown above, looking more like a swirl of shampoo in a draining bathtub than an ominous hurricane.

It's tried to get its act together since then. As of about 7:00 PM EDT, strong thunderstorms are trying to redevelop on the northern side of the circulation, and it wouldn't take much organization to allow the storm to regain its footing. Satellite data and aircraft reconnaissance showed the storm teetering between 70 and 75 MPH late this afternoon, which is the line between tropical storm and hurricane. There's not much of a practical difference between a strong tropical storm and a minimal hurricane. Given the uncertainty and the storm's tenacity, tropical storm and hurricane conditions still appear likely over a large swath of the Florida Peninsula over the next 24-36 hours.

The 5:00 PM forecast from the National Hurricane Center calls for Isaias to regain hurricane strength as it comes perilously close to landfall in Florida. The storm will scrape Florida's east coast through Sunday evening before it moves back over open water toward the Carolinas. Watches and warnings will accompany the storm up the coast; remember that these advisories don't only exist along the shoreline, and hurricane and tropical storm force winds are possible well inland from the coast.

Heavy rain will remain the greatest threat from Isaias the farther north you go. The Weather Prediction Center's rainfall forecast this afternoon paints 3-5 inches of rain along the path of the storm, which covers almost the entire length of Interstate 95. This much rain falling this fast will lead to the potential for widespread flash flooding, especially in areas that have seen heavy thunderstorms recently.

[Satellite: NOAA]

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July 31, 2020

Here's Your Friday Night Update On Hurricane Isaias As It Approaches Florida

Hurricane warnings are up for portions of southeastern Florida as Hurricane Isaias (pronounced ees-ah-EE-ahs) traverses The Bahamas on Friday night. The hurricane's outer bands will begin to affect the Miami area during on Saturday, with conditions rapidly deteriorating Saturday night and through the day on Sunday. Most of the U.S. East Coast and the Canadian Maritimes are at risk of seeing strong winds and heavy rain from this storm through early next week.

Hurricane Isaias

Isaias is a resilient storm. After several days of struggling to develop in the eastern Caribbean Sea, the system got its act together in a hurry over Hispaniola. While the island's rough terrain typically brings tropical cyclones to a hasty end, the center of what became Isaias seemed unaffected by the terrain. The system rapidly strengthened into a hurricane on Thursday night and it's maintained intensity over the last 24 hours.

It looks interesting on satellite imagery. Radar shows an eyewall developing, but dry air on the western side of the storm won't let the eyewall fill in, precluding an eye from clearing out in the clouds. There's a large mass of convection on the eastern side of the storm, while the western side is struggling against that dry air and a bit of wind shear.

Forecast Track

The National Hurricane Center's forecast at 11:00 PM EDT on July 31, 2020, shows the hurricane dragging along Florida as a hurricane before skirting up the entire U.S. East Coast and into the Canadian Maritimes as a strong tropical storm.

Accordingly, a whole slate of watches and warnings are up for the Florida Peninsula, including a hurricane warning for coastal counties from Boca Raton, Florida, northward to the Volusia/Brevard County line (just north of Cape Canaveral). Expect these alerts to extend up the coast over the next few days.

If the storm remains on its current projected path, the storm will affect the entire coast from Miami to Halifax. The greatest threat right now appears to exist in both Florida and North Carolina, both of which could feel the strongest winds, rain, and storm surge with the closest approach of the system's core.

Forecasters expect Isaias to maintain strength and gradually weaken as it picks up speed and begins to curve up the coast. The environment around the hurricane isn't too friendly for strengthening, but it's not out of the question once the core of the storm moves over the Gulf Stream. Remember, storms can unexpectedly intensify, which is a dangerous prospect when they're this close to land.

Wind & Storm Surge

Hurricane force winds appear most likely in southeastern Florida, which could see the center make about as close of an approach as possible without actually making landfall. Tropical storm force winds are possible over a wider area, including counties that are dozens of miles inland.

The hurricane's projected path scrapes the eyewall over many dozens of miles of land; we could see entire counties go through a period of damaging winds. Widespread power outages are likely. 

The latest NHC forecast shows a potential storm surge of 2-4 feet above normal tide levels across much of eastern Florida. Their new map—which is quite useful compared to some of their old storm surge graphics—is shown above.


As usual, the threat for freshwater flooding from heavy rain is the greatest threat anyone in the path of the storm will face. The latest seven-day rainfall forecast from the Weather Prediction Center is shown above. Isaias could produce several quick inches of rain along its path, potentially leading to flash flooding. Some areas could wind up with more rain than predicted above. A track closer to land would bring higher rainfall totals for more people than a track that brings the core of the system farther away from land. 

Most of the deaths in a landfalling tropical cyclone occur as a result of flooding from heavy rain. Never cross a water-covered roadway. It's impossible to judge how deep the water is until it's too late, and it takes a surprisingly small amount of moving water to lift up a vehicle and carry it downstream.


There's enough spin in the atmosphere that tornadoes are always a concern when a tropical cyclone makes landfall (or brushes land). The greatest threat for tornadoes usually exists in the right-front quadrant of the storm relative to its forward motion. Since that right-front quadrant is likely going to stay offshore, the tornado threat is a little lower. That said, some of the storm's outer bands could produce a quick tornado or two. Tropical tornadoes are fast and they can occur with little or no lead time. Always stay alert and make sure you can get to a safe spot in a hurry if needed.

[Satellite Image: NOAA]

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The Weather Channel's "COVIDCANE" Branding Is A Mockery Of This Crisis And Its Own Legacy

Any hurricane season is stressful when we have a storm aiming for the coast, but this season is particularly harrowing because of the ever-worsening coronavirus pandemic. It's not out of question that coastal communities will face evacuation orders at some point this season due to a storm's surge or inland flooding. When that happens, local officials will have to walk a tightrope to figure out how to safely handle evacuees without exposing folks already experiencing hardship to a coronavirus outbreak at evacuation centers and other gathering points for aid and supplies.

The Weather Channel, bless its heart, decided to call this conundrum COVIDCANE 2020: BRACING FOR DISASTER.

Come on.

The network recently ran a special report titled COVIDCANE 2020 and I held hope, however fleeting, that it was a one-off thing and the folks in charge would think better of this ill-advised branding opportunity.


Watches and warnings are up in parts of Florida ahead of Hurricane Isaias. The Weather Channel's on top of it like always. But right next to their coverage tonight is that little COVIDCANE 2020 logo, hanging out on the network's graphics and chyrons like a sorry wasp caught between the screen and the window.

How many desks did COVIDCANE 2020 have to cross before it got final approval to go on television and the internet? How many folks had to give this branding nightmare the green light and no one stopped to think for one blasted minute "hey, maybe we shouldn't do this?"

I have been in that building twice. There are lots of fantastic people who work for the company. And the building has plenty of cozy meeting rooms for any number of those great folks to go over what went wrong and make sure it doesn't happen again.

I've criticized The Weather Channel for plenty of nonsense in the past. Their winter storm names are flawed. They've given some pretty boneheaded advice during emergency situations. One of their reporters ran around in a hurricane a few years ago like a frat guy during pledge week—I hear they even wound up changing the way they cover storms after that incident.

But this is something that's completely out of character for a network that prides itself on leading the pack for weather coverage. They're supposed to be the gold standard—weather you can always turn to!—but this escapade cracks open the vault to find an empty reserve and an intern pecking at a keyboard in the dark.

The Weather Channel didn't invent over-the-top branding during natural disasters. News organizations have been packaging flashy graphics and snazzy music for crises since they got the technology. But the company should know better. More than 150,000 people are dead from a virus in five months. We're adding tens of thousands of new cases every day. A hurricane is heading toward the worst-hit part of the country right now and goodness knows what else will form in the coming months.

This is stress on top of stress.

We all know the power of graphics, chyrons, and headlines. Advertising this as COVIDCANE 2020 cheapens the threat and makes it sound like it's just another ratings opportunity instead of a serious examination of two disasters converging in a way we haven't experienced in living memory in the United States.

Do better.

[Images: @weatherchannel on Twitter (1 & 2)]

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July 27, 2020

Get Ready To Learn How To Say "Isaias," The Atlantic Hurricane Season's Next Storm Name

This year's Atlantic hurricane season is off to a record start, giving us the most named storms we've ever recorded this early in the summer. The next name on the list for storms in the Atlantic is Isaias, which is pronounced exactly as it looks—ees-ah-EE-ahs.

Just about every meteorologist who's endeavored to teach their audiences how to say the next storm's name have been tagged by comment thread hotheads who are a-n-g-e-r-y that other languages exist, and the performative outrage is sure to spread once folks on the news start saying ees-ah-EE-ahs with every broadcast.

Admittedly, it's a bit tricky for native English speakers who aren't accustomed to the abundance of accented vowels in Romance languages like Spanish and Portuguese, but it's a quick and simple four syllables that are worth a few seconds to learn.

How'd we get here already?

We're eight names and five landfalls into the 2020 Atlantic hurricane season and the peak of the season is still more than a month away. The year began with Tropical Storm Arthur in the middle of May—more than two weeks before the start of the season—and kept going with several quick storms over the following weeks.

Thankfully, most of the storms were relatively weak and not long for this world. While we're way ahead of normal in raw numbers, we're not far off par for Accumulated Cyclone Energy (ACE), which is the best measure of the true intensity of a hurricane season.

The record pace at which we're knocking through storm names brings some attention to the very practice of naming storms itself. The attention is that much greater now that we're about to have a slightly tough-to-pronounce name that has the added bonus of whipping up Facebook's resident curmudgeons because it's not lazily pronounced the English way (eye-ZAY-us).

Tropical cyclone names for the world's ocean basins are maintained by the World Meteorological Organization, the agency within the United Nations that coordinates global standards in meteorology. It's important for this central organization to maintain the official list of names around the world or each country (and company...cough...) could assign its own name to each storm, creating a nightmare for communication and a breeding ground for confusion.

The Atlantic Ocean has six lists of names; each list is used once every six years. The current lists were introduced back in 1979. Each list is populated with names that alternate between masculine and feminine, omitting several letters at the end of the alphabet (Q, for instance) because there just aren't that many common names that begin with those letters.

Each name is drawn from suggestions submitted by countries that border the Atlantic Ocean. Since the countries around the Atlantic predominantly speak English, Spanish, and French, we wind up with a nice mix of names—Dolly, Gonzalo, Margot—that represent the different languages of the Atlantic Basin.

While we've been using the same batch of names for decades, many of the names have been swapped out from the originals due to retirements. The WMO holds an annual meeting to determine if any of the names deserve retirement because the storm was particularly destructive or deadly. Understandably, it'd be uncomfortable (and confusing!) to talk about another Hurricane Harvey rolling into the Gulf of Mexico, so they retired that name and replaced it with Harold for the list that'll be used again in 2023.

This year's list used to feature the names Gustav, Ike, and Paloma, all of which were retired after the destructive 2008 hurricane season. The WMO replaced those names with Gonzalo, Isaias, and Paulette, respectively, but we never got around to using Isaias or Paulette in 2014 due to the below-average activity in the Atlantic that year.

It's almost certain that we're going to see the first appearance of a storm named Isaias this year, a name drawn from the many Spanish- and Portuguese-speaking countries that border the Atlantic. It's ees-ah-EE-ahs, not eye-ZAY-us. It's clearer when it's written properly—Isaías, with the accent—but the official name lacks the accent for ease of use in official products. (It'd take a long time to issue products if meteorologists had to hit ALT+161 on their keyboard every time they want to type the í in Isaías.)

You can see the National Hurricane Center's pronunciation guide for all the names used in the Atlantic Ocean and eastern Pacific Ocean over at the agency's tropical cyclone naming page. Most of the other names used this season are straightforward; Laura is LOOR-uh instead of LAW-ruh, but I suppose that's a fight over accents as opposed to languages, in which case y'all just gotta fight that one out.

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July 24, 2020

Two Hurricanes Could Make Landfall This Weekend: One In Texas, The Other In Hawaii

This weekend could see the rare occasion when two different hurricanes make landfall in the United States just one day apart. The latest forecast from the National Hurricane Center predicts that Tropical Storm Hanna will reach hurricane strength before coming ashore near Corpus Christi, Texas, on Saturday, followed by the potential landfall of Hurricane Douglas on the Hawaiian Islands on Sunday.

Texas: Tropical Storm Hanna

Hanna is doing its best to take full advantage of the environment over the Gulf of Mexico. The storm has a mean look to it on satellite imagery—that's a technical analysis, of course—with a broad curvature, decent upper-level outflow, and deep convection around the center of the system. Pretty much the only good thing we've seen so far is that the storm's ingested a bit of dry air into its core, slowing down the rate of organization and strengthening.

Even so, given its current organization and the favorable environment ahead of it, the NHC expects the system to make a run at hurricane strength before making landfall on Saturday afternoon.

Flooding Rains

The big story with Tropical Storm Hanna is the flooding. Some areas could see up to a foot of rain from this storm over the next couple of days. It won't take much heavy rain to produce flash flooding, especially in arid areas where the ground isn't capable of absorbing water as efficiently. 

A risk for flash flooding exists along Hanna's general track, where the Weather Prediction Center expects a broad swath of 4-8 inches of rain from the coast into northern Mexico.

Freshwater flooding is the leading cause of death from a landfalling tropical system in the United States. Inevitably, someone will think they're invincible or that they've got impeccable judgement and they'll try to drive across a flooded roadway only to get stuck and washed downstream. It's impossible to judge how deep the water is before you're in it and it's too late. It takes a surprisingly small amount of water to lift a vehicle and carry it downstream. 

Wind and Surge

Current forecasts bring the center of the storm ashore near Corpus Christi on Saturday afternoon. Normally, this is the part where I'd stress that the forecast only applies to the center of the storm, and the wind, rain, and storm surge can extend hundreds of miles from the eye. That'll certainly be the case with Hanna's flooding rains. However, this is a compact storm with a compact core of strong winds. It very much matters where it makes landfall; a few miles north or south could mean the difference between a breezy day and a solid thump in a city that's home to more than 300,000 people.

There's little difference between a 70 MPH tropical storm and a 75 MPH hurricane, so its title doesn't matter much but to folks who love technicalities. Wind damage is likely where the core of the storm comes ashore, but tropical storm force winds extend several dozen miles away from the center and it won't take much wind to knock down trees and power lines when the soil is wet.


A risk for tornadoes exists with any landfalling tropical cyclone. The greatest threat for tornadoes lies in the right-front quadrant of the storm relative to its forward motion—in Hanna's case, that's going to be the northern side of the storm.

Tropical tornadoes happen fast and, as a result, they often touch down with reduced lead time. They're more common in the rain bands than the shield of rain around the center of the storm itself, but they can occur close to the center if an embedded thunderstorm can tap into enough spin in the atmosphere.

Hawaii: Hurricane Douglas

Not even 24 hours after Hanna hits Texas, we'll have to look a few thousand miles west and watch nervously as Hurricane Douglas closes in on Hawaii. A hurricane watch is in effect for the Big Island, Maui, Lanai, Molokai, and Kahoolawe, which includes the cities of Hilo and Kahului. It's likely watches will be extended west toward Honolulu over the next day or so.

Douglas strengthened into a major hurricane this week. It's going to begin a slow but steady weakening trend over the next few days as it traverses cooler waters near Hawaii. Previous storms that approached Hawaii in recent years fell apart in dramatic fashion as they approached the Big Island. Forecasters expect Douglas to weaken slowly, though, due to low vertical wind shear trying to tear the storm apart.

The latest forecast shows the storm traversing the length of the island chain. Conditions will rapidly deteriorate on the Big Island on Saturday evening, worsening across the islands from east to west through the day on Sunday.


Douglas, like Hanna, has a relatively small core of strong winds around the eye of the storm. However, Douglas' predicted track could expose most population centers in the state to a period of dangerous conditions this weekend. A small wobble in either direction could have huge implications in who sees the worst weather.

Hurricane conditions are possible on portions of the Big Island and Maui if the center tracks very close to land. This kind of wind will lead to widespread tree damage, lengthy power outages, and structural damage. Falling tree limbs are a serious danger to motorists, pedestrians, and homes; if you live in Hawaii and you're in the path of the storm, stay away from rooms where large trees or limbs could fall through the roof or walls.

Heavy Rain

Flash flooding is a serious hazard with Hurricane Douglas. The mountainous terrain allows heavy downpours to turn into flash floods and mudslides in a hurry. The Central Pacific Hurricane Center warns that 6 to 10 inches of rain are possible, with total amounts of more than a foot of rain possible along the windward side of high terrain. 

[Satellite: NOAA]

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July 23, 2020

Two Atlantic Storms Heading For Land; Flooding Threat Growing On Gulf Coast

A tropical storm warning is in effect for a portion of the Texas coast as a tropical depression drifts west across the Gulf of Mexico. The system, regardless of its status at landfall, could bring heavy rain and rough seas to coastal communities from Brownsville to Mobile. While that's the immediate concern, there's a strengthening tropical storm far out in the Atlantic that we'll need to keep an eye on as it moves into the Caribbean later this week.

Tropical Depression Eight

Satellite imagery and Hurricane Hunter aircraft found that the tropical disturbance in the Gulf of Mexico developed into a tropical depression on Wednesday afternoon. It's struggled to maintain its composure a bit over the last 24 hours, but it's starting to look healthier on satellite imagery today and it might make it to tropical storm strength before too long.

The NHC's forecast turns this into Tropical Storm Hanna by Friday, bringing it into the coast on Saturday with maximum winds near 60 MPH. That's enough to bring down trees and power lines, especially where the soil is loose from the heavy rain. A tropical storm warning is in effect for the coast and inland counties around where the system/future-Hanna is forecast to make landfall, including Corpus Christi and Victoria.

Heavy rain is the greatest threat from this system no matter what it's called by the time it reaches land. Some communities could see up to half a foot of rain if they're caught beneath training bands of heavy showers and thunderstorms. The greatest rainfall totals are likely near where the system makes landfall this weekend, but rain associated with the system will bring the potential for flooding as far up the coast as Mobile, Alabama, where forecasters expect several inches of rain through next week.

Tropical Storm Gonzalo

Gonzalo is our seventh named storm of the year, setting yet another record for the most named storms so early in the season. We typically don't see our first hurricane until mid-August and it usually takes until the peak of hurricane season to reach our seventh named storm. (If the tropical depression in the Gulf becomes Tropical Storm Hanna, that will set another record for the earliest "H" storm.)

This is the first tropical system we've seen form out in the tropical Atlantic Ocean, an area between the Caribbean and the west coast of Africa known as the "main development region," or MDR. With the exception of Tropical Storm Cristobal, every other storm we've seen in the Atlantic in 2020 developed from non-tropical origins.

The tropical storm might undergo a period of intensification soon and the National Hurricane Center's forecast calls for Gonzalo to reach hurricane strength by Thursday. A hurricane watch and a tropical storm watch are in effect for the Windward Islands in the path of the storm. This is a tiny storm right now; the 5PM advisory found its tropical storm force winds only extended about 25 miles from the center of the storm. Gonzalo's precise track will determine which islands see the worst conditions, especially if the storm remains compact as it is now.

Forecasters expect Gonzalo to continue into the Caribbean on a general weakening trend through the weekend. It's a bit of an open question right now whether the storm will completely degenerate once it reaches the Caribbean or continue to hang on as it treks west. If it hangs on, there's a chance it could redevelop in the western Caribbean this weekend or early next week.

[Satellite Image: College of DuPage]

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