10:00 AM | *Hottest weather so far this summer expands to the Mid-Atlantic/Northeast US for Wednesday, Thursday and Friday…transition day likely on Saturday as cooler air should return by Sunday*
Paul Dorian
Hot air that has been confined to the SW US in recent days will expand to the north and east at mid-week resulting in the hottest weather so far this summer on Wednesday, Thursday and Friday in the Mid-Atlantic region and Northeast US. The hottest conditions “relative-to-normal” will take place across the central states where temperatures can reach 15 degrees above-normal for the latter part of July. Maps courtesy NOAA, tropicaltidbits.com (loop of 850 mb temperature anomalies from Wednesday morning to Sunday morning)
Overview
The hottest weather of the summer season so far is headed to the Mid-Atlantic region and Northeast US for the Wednesday, Thursday and Friday time period. The hot weather can extend into Saturday, but it looks like a cool front will approach the region and a transition back to cooler conditions takes place for the second half of the upcoming weekend. The hottest day in this upcoming stretch could turn out to be on Friday when temperatures climb well up into the 90’s along much of the I-95 corridor and the DC metro can even have a flirtation with the 100 degree mark.
Hot air in the SW US in recent days has been as a result of intense upper-level ridging and this system will expand to the north and east at mid-week and then retreat back to the central and western states this weekend. Maps courtesy NOAA, tropicaltidbits.com (500 mb height anomalies from Wednesday morning to Sunday morning)
Details
The last time Washington, D.C. reached the 100 degree mark was on August 15, 2016 and this is the longest streak without hitting the century mark since 1977 and overall the 6th longest since 1872. There is an outside chance of reaching 100 degrees on Friday in DC which is likely to be the hottest day in this upcoming heat wave for the Mid-Atlantic region and Northeast US. Intense high pressure in the upper part of the atmosphere has been centered over the Four Corners region of the US in recent days, but it will expand to the north and east by mid-week. As a result, the hotter-than-normal air mass that has been confined to the southwestern states recently will expand first to the Central Plains and then to the Mid-Atlantic and Northeast US for the second half of the week.
Possible high temperatures on Friday are reflected here on this forecast map by a blend of computer forecast models. Map courtesy weathermodels.com (Dr. Ryan Maue, Twitter), NOAA
Temperatures are likely to reach 90+ degrees on Wednesday afternoon in the DC-to-Philly-to-NYC-Boston corridor and the heat should remain through Friday with mid and upper 90’s highs possible at the end of the work week…perhaps even a flirtation with the century mark in Washington, D.C. This upcoming hot stretch of weather will be even more intense “relative-to-normal” across the center of the nation with temperatures as much as 15 degrees above normal for the latter part of July. The three-day heat wave on Wednesday, Thursday and Friday will not necessarily come without showers and thunderstorms in the Mid-Atlantic/NE US. Indeed, a couple of waves of energy can produce some shower and thunderstorm activity later in the week across the Mid-Atlantic region and Northeast US to go along with the expected hot conditions.
Cooler-than-normal conditions are likely to return to the Mid-Atlantic region and Northeast US for the second half of the upcoming weekend following the passage of a cool front. This transition back to cooler weather will come after the hottest stretch so far on Wednesday, Thursday and Friday. Map courtesy NOAA, tropicatidbits.com
The seeds for the end of the upcoming heat wave are already being planted across Canada. A cooler-than-normal air mass is building up there and will drop to the south and east by the weekend. A strong frontal system is likely to approach the Mid-Atlantic/NE US during the first half of the weekend and there certainly can be some heavy shower and strong thunderstorm activity associated with this system as we transition back to the cooler conditions by Sunday. Whether the temperatures can spike back into the 90’s on Saturday ahead of the front for one more hot weather day is a little too early to say, but it is on the table. Temperatures could then drop back to below-normal for the second half of the weekend following the passage of the cool front.
Meteorologist Paul Dorian
Arcfield
arcfieldweather.com
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