Heat recommendations targeting Missouri cover parts of 13 states in the central and southern plains to the mid-south. There are additional advisories for much of the Northeast Urban Corridor. Excessive heat warnings are also in effect for 10 million people in the desert southwest on Friday.
Both Boston and New York City have changed triathlon plans for the weekend. It’s been in Boston postponed to Augustand New York City’s has been cut by about half.
further south, Washington, DC, remains under a mayor-declared heat emergency until Monday. City pools will be open late, while shelters and cooling centers will also be available.
In Texas and much of the Southern Plains, ranchers and ranchers struggle with scorched fields and stressed livestock. The persistence of hot and dry conditions is unheard of in parts of the region.
Dozens of record highs have already been broken in recent days, and about three dozen could be threatened over the weekend. Numerous records for warm lows are also likely.
Friday there is a warning of extreme heat for much of the desert southwest, including Phoenix, Las Vegas and Palm Springs, California.
“Far above normal high temperatures today are likely to reach 110 to 115 degrees for Phoenix and all lower desert communities across the region,” the Weather Service wrote there.
This is on the heels of some record highs Thursday. They include Barstow, California, at 112; Bishop, California, at 106; and Desert Rock, Nev., at 108. A record low of 90 was also tied in Las Vegas. In Needles, California, the low at night was a remarkable 95 on Wednesday.
Friday is likely to be the last of this current period of excessive heat for the region as temperatures return to normal levels around 100 after that. Humidity associated with the summer monsoon – a shift in wind that brings rain to the region – will forecast to increase, which helps build clouds and lower temperatures.
Temperatures of 100 or higher have been the norm for weeks across the southern plains and the mid-south. Prolonged drought and the spread of a sudden drought only increase the feedback loop between dry and warm conditions.
On Thursday, a slew of record highs fell in Texas, including San Antonio, where it hit 102. It was the fifth record this month, on top of eight record highs in June and eight in May. The city now has 42 days at or above 100 in 2022, compared to an average of 19 for an entire summer.
San Antonio had 17 days of triple-digit heat in June. The standard is two.
Additional record highs on Thursday included Houston (at Hobby Airport) at 100, Austin at 103 and College Station at 105. Numerous Texas locations, such as Abilene and Dallas, also set record warm lows for the date.
Mercury rises in the mid-Atlantic and northeast
While the Northeast has avoided extreme heat so far this summer, the region is experiencing its hottest weather of the season yet over the weekend.
Boston, Providence and Hartford, as well as coastal areas such as Cape Cod, will face heat advisories Saturday and Sunday. Temperatures inland are expected to reach record-challenging highs to around 100 in the mid-90s, while cooler coastal locations also rise to near or above 90.
It’s a similar story in New York City and Philadelphia, where a heat advisory runs Friday through Sunday, and each day the readings should reach at least the mid-to-top 90s.
“There will be a chance that a few spots could reach extreme heat warnings on Sunday, and this will need to be monitored in future forecasts,” NWS New York City wrote.
Urban New Jersey and parts of New York City are most at risk for meeting heat warning criteria, including heat index values approaching 110. Newark, in the middle of a major urban heat island, has hit 100 twice this week.
DC heat wave: Sunday could turn 100 for the first time in six years
From the DC and Baltimore metro areas to Richmond, temperatures will soar into the mid-90s on Friday, peaking at 90 to nearly 100 this weekend. Additional heat warnings seem like a good bet for these areas.
Numerous record highs are in play before a cold front puts a temporary halt to the brutal temperatures early next week. Sunday is probably the hottest day of the stretch and many records could be set.
In addition to the high temperatures during the day, lighting at night will be minimal. Temperatures in urban areas may not dip much below 80, while others dip deeper into the 70s.
Next week a return of Northwest heat
So far, this summer has been relatively tame in much of the Pacific Northwest. But early next week, high pressure from the Gulf of Alaska is building into the area, setting the stage for the hottest weather of the year yet.
“Western Washington will experience an extended period of well above normal temperatures and dry conditions in the long term,” NWS Seattle wrote.
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Warm weather takes over Monday and lasts much of the work week. With temperatures in the 90s throughout the days, heat warnings may be issued in parts of the area as the forecast gets closer.
A large high-pressure “heat dome” has been anchored in the southern United States for weeks. Sometimes it is extended to reach the west coast and the east coast.
Sinking air under high pressure tends to hinder the development of clouds and thunderstorms, maximizing the amount of summer sun shining down. Just over half of the Lower 48 is under drought, according to the U.S. Drought Monitor update released Thursday. Nearly 70 percent are categorized as at least abnormally dry.
Drought and high pressure often go hand in hand. The extended stay of the heat dome has helped to sustain the drought and high temperatures.
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Human-induced climate change also increases heat. Temperatures tend to get a few degrees warmer than they would otherwise be without it — and that is underlined by this summer’s weather in the United States and worldwide.