The next three days will likely be the hottest stretch all summer long in the Mid-Atlantic region with urban areas along Route I-95 likely to make a run at the 100 degree mark (e.g., DCA, PHL, NYC) over the weekend. (Philly Airport hasn’t reached the 100 degree mark in the last 7 years). There is significant relief coming to the Midwest, NE US and Mid-Atlantic region next week and temperatures are quite likely going to be below-normal on Tuesday and Wednesday. The transition from the extreme heat and humidity expected this weekend to the cooler-than-normal conditions next week may very well come with strong-to-severe thunderstorm activity in the Sunday night to early Tuesday time period with more torrential rainfall and potential damaging winds.
There is no doubt there will be high heat and humidity this weekend in the Mid-Atlantic region, Midwest and NE US as high pressure intensifies in the upper part of the atmosphere. Temperatures could make a run for 100 degrees on each weekend day in the I-95 corridor region from DC-to-NYC and overnight lows will be very high not falling below 80 degrees in many urban areas and inhibited in falling by extremely high moisture levels in the lower atmosphere. A strong cool front will approach the region by the early part of next week and it will usher in big changes by the middle of next week.
Showers and thunderstorms are possible on the back end of this heat wave for Sunday night, Monday, Monday night and even early Tuesday and, much like the front end thunderstorms on Thursday, they can reach strong-to-severe levels with the potential of heavy rainfall, flash flooding and damaging winds. A weak disturbance will cause scattered showers and thunderstorms on Sunday night with some heavy rainfall and then a sharper wave in the upper atmosphere associated with a strong cool front will cross the Great Lakes on Monday. This front may not work its way to off the east coast until sometime later Tuesday so it may result in lingering shower and thunderstorm activity into the morning hours on Tuesday.
Once the front clears the coast, much more comfortable air will push into the Midwest and Mid-Atlantic and highs may actually turn out to be several degrees below normal on Tuesday and Wednesday as a trough of low pressure forms aloft in the eastern US. The big change in the pattern could actually bring about reasonable temperatures in the central and eastern US for the remainder of July and perhaps even into the early part of August.
Meteorologist Paul Dorian