It's been an exceptionally hot summer for vast swaths of the United States so far, with a slew of longstanding records shattered in the desert southwest and unforgiving stretches of high heat and humidity in the southern states.
The heat will extend toward the Atlantic and park over the eastern states heading into the final weekend of July. Highs in the 90s will stretch far into New England, with daytime temperatures likely cracking the triple-digit mark in Virginia and Maryland.
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Calling temperatures in the desert southwest "exceptionally hot" almost feels like an understatement given what they've been through for the past month.
Phoenix continues to pad its record-smashing streak of daytime highs reaching 110°F or hotter, with July 25 coming in as their twenty-sixth day of 110-degree-or-hotter heat. Tuesday's high in Phoenix climbed to 118°F.
The National Weather Service expects Phoenix's high to meet or exceed 110°F through Saturday before the potential 30-day streak has a chance to finally end on Sunday.
El Paso, Texas, also continues to pad its own streak of consecutive days with a triple-digit high temperature. Tuesday was the city's 40th day with a high of 100°F or hotter, and the NWS expects it won't be until Sunday or Monday that El Paso has the opportunity to 'cool down' and break their historic run with a high of only 98°F or 99°F.
Introducing the newest Oklahoma Mesonet extreme: 126F heat index at the Paul’s Valley site. This is our highest ever heat index measurement in our nearly 30 year history. 😳#okmesonet #okwx pic.twitter.com/OPGijwGYNV
— Oklahoma Mesonet (@okmesonet) July 13, 2023
This heat hasn't just stayed in the southwestern corner of the country. We've seen brutal heat build across the southern states and the Plains over the past couple of weeks. The Oklahoma Mesonet likely recorded its all-time highest heat index on July 13 with a 126°F heat index south of Oklahoma City.
The heat index combines the air temperature and the dew point to calculate how hot it feels to your body. A heat index of 126°F is pretty close to the upper end of what the human body can endure for any length of time.
And now it's the East Coast's turn to deal with the heat.
The intense ridge of high pressure parked over the southwest expanded east this week, pushing heat deep into the Plains and Midwest. Heat advisories are up for vast swaths of the central part of the country as triple-digit highs are likely this week as far north as South Dakota and Minnesota.
A separate ridge will build over the western Atlantic and the East Coast for the second half of the week, the strength of which will crank up the heat for the eastern half of the country while forcing that desert heat dome to weaken a bit. This give-and-take is the driving force behind forecasters finally seeing an end to those historic runs of extreme heat in places like Phoenix and El Paso.
As the ridge strengthens, daytime highs will climb into the upper 80s and 90s for several days beginning Wednesday and lasting into the weekend for some areas.
Friday looks to feature the worst of the heat, when highs will climb well into the 90s along pretty much the entire eastern seaboard. Only folks at higher elevations or right on the water will be spared from the full intensity of the high heat.
Most communities along the megalopolis will reach the upper 90s on Friday, with heat indices soaring past 100°F when you factor in the humidity. It's possible that Baltimore and maybe D.C. could crack triple-digits for a little while on Friday afternoon.
Thankfully, this won't be an extended heat wave, but several days of hot daytime highs with muggy nights will make conditions extremely uncomfortable for folks who live without access to air conditioning or who work outside for long periods of time.
It's not just vulnerable people who are exposed to heat-related illnesses. Heat exhaustion and heat stroke can set in quickly with this kind of heat, even in folks who are physically fit, as those who exercise or work outside regularly tend to underestimate the heat and overdo it thinking they'll be fine.
[Top image via Tropical Tidbits]
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