11:15 AM | **Excessive heat in the Mid-Atlantic for Friday, Saturday, Sunday…Barry’s remains to enhance chance for showers and thunderstorms at mid-week and some rain can be heavy**
Paul Dorian
Latest NEXRAD image features a large area of rain in the Mississippi Valley region associated with the remains of Barry; courtesy NOAA, University of Wisconsin/AOS
Overview
There are two big weather stories unfolding for the week and weekend in the Mid-Atlantic region with the potential of some heavy rainfall at mid-week from the remains of Barry and then the hottest weather of the summer so far for the Friday, Saturday, Sunday time frame and perhaps even into the early part of next week. Showers and thunderstorms are likely from later Wednesday into Thursday in the DC-to-Philly-to-NYC corridor mainly as a result of the remains of Barry and some of this rain can be heavy at times. Once this large moisture field pushes away, the excessive heat will become the main story with mid-to-upper 90’s possible for highs in DC, Philly and NYC this weekend and triple digits is on the table.
The slow movement of Barry over the Gulf of Mexico resulted in strong upwelling which brought cooler-than-normal water to the surface which will inhibit tropical activity for the next few days; courtesy NOAA, tropicaltidbits.com
Mid-week heavy rain threat with Barry’s remains
Barry came ashore early this weekend in central Louisiana as a weak (cat 1) hurricane and dumped lots of rain across the central Gulf coastal region. The winds were never really a factor down there, but the rainfall was certainly on the high side with some spots receiving more than a foot. The remains of Barry are now creating significant rainfall in the Mississippi Valley region and this area of moisture will continue to head towards the Mid-Atlantic. There will be a noticeable increase in heat and humidity on Tuesday afternoon and evening in the Mid-Atlantic and showers and storms will threaten, but an even greater chance will come later Wednesday as moisture arrives from Barry’s remains. Some of the rain late Wednesday into Thursday can be on the heavy side in the I-95 corridor – nothing new for this very wet long-standing weather pattern.
There is lots of dry (Saharan Dust) air over the Atlantic Ocean (indicted by orange, red) and this will continue to inhibit the formation of “African-wave” type tropical storms; courtesy NOAA, University of Wisconsin/CIMSS
Now that Barry has weakened and pushed inland, the overall Atlantic Basin tropical scene is rather quiet. There remains quite a bit of dry (Saharan Dust) air over the tropical Atlantic and this will continue to inhibit “African-wave” tropical storm formation in the eastern Atlantic. Barry was a “home-grown” type of tropical system which formed close by over the warmer-than-normal waters of the Gulf of Mexico and did not originate in the Atlantic. One final note of interest, upwelling took place underneath Barry as it churned over the Gulf of Mexico during late last week and weekend and this has brought cooler-than-normal waters to the surface which may inhibit tropical activity there for the next several days.
A strong ridge in the upper atmosphere (500 mb) will form over the Mid-Atlantic region by the weekend and this will result in a stretch of excessive heat; courtesy NOAA, tropicaltidbits.com
Excessive heat
Once Barry’s moisture field pushes away from here later this week, the door will be open for very hot air to move into the Mid-Atlantic region from the west and southwest. As a result, temperatures could soar to the mid and upper 90’s for highs on Friday in the DC-to-Philly-to-NYC corridor and the same pattern is likely on Saturday, Sunday and perhaps on Monday as well. In fact, triple digit highs are on the table for this hottest stretch of weather so far coming this way by the weekend. Longer term, there will be cooler-than-normal air pressing into the middle of the country early next week and this is likely to bring an end here to the upcoming stretch of hot weather.
Forecast map of 850 mb temperature anomalies features excessive heat in the Midwest, Mid-Atlantic and NE US as of Saturday evening; courtesy NOAA, tropicaltidbits.com
Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com
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