11:15 AM (Thursday) | ***Heavy rain and severe weather threat later today and tonight greatest in the Deep South…threat shifts to the east coast late tomorrow and tomorrow night***
Paul Dorian
Vigorous upper-level energy in the eastern US late Friday will be a major contributor to heavy rainfall and the threat of severe weather; courtesy NOAA/EMC, tropicaltidbits.com
Overview
Deep upper-level low pressure will intensify over the next 24 hours as it slowly grinds its way across the southern states. The combination of this strong wave of energy in the upper atmosphere and an influx of very moist tropical air will result in a severe weather threat later today and tonight in the Deep South. In addition to the severe weather threat which includes the potential for hail and isolated tornadoes, heavy rainfall is likely later today in the southern states and localized flooding is a concern as grounds are well saturated. The threat for heavy rainfall and severe weather will shift to the eastern seaboard late tomorrow and tomorrow night with the possibility of strong-to-severe thunderstorm activity extending from the Mid-Atlantic region to Florida.
NOAA’s Storm Prediction Center (SPC) forecast map of severe weather probabilities today (left) and Friday (right) with greatest potential shifting from the Deep South to the east coast
Details
Deep upper-level low will pull out of the south-central US today and intensify as it slowly treks across the southern states. A strong and slow-moving cold front associated with this upper-level feature will grudgingly works its way to the eastern seaboard over the next few days and this slow movement and strong upper-level support will combine with an influx of tropical moisture to raise the chances for a major rain event in the much of the eastern third of the nation between today and early Saturday as well as the threat for severe weather.
Tropical moisture as depicted here by “total precipitable water” is already surging northward from the Gulf of Mexico into the south-central US; courtesy University of Wisconsin/CIMSS
The threat for severe weather including hail and possible tornadic activity will be greatest late today and tonight in the southern states of Louisiana, Mississippi and Alabama and then will shift to the east coast late tomorrow. Along with the severe weather threat, flooding rainfall is possible in these same areas as the upper-level low slowly inches to the east. Grounds are well saturated in much of the eastern third of the nation and any heavy rainfall over the next couple of days can result in localized flooding.
Tropical moisture will flow up the east coast on Friday and combine with strong upper-level energy to produce heavy rain and potential severe weather; map courtesy NOAA/EMC, tropicaltidbits.com
The threat of heavy rain and severe weather will shift to the eastern US late Friday with severe thunderstorm activity possible from the Mid-Atlantic region to Florida. The greatest chance for torrential rainfall and severe thunderstorm activity in the eastern states will come late in the afternoon on Friday and especially tomorrow night. While the steadiest and heaviest rain will end by early Saturday, it looks like an unstable weekend in the Mid-Atlantic region as the upper-level low will still be positioned to the west of the region. As a result, instability showers are quite likely on Saturday in the DC-to-Philly-to-NYC corridor and there can be an isolated thunderstorm. By Easter Sunday, the upper-level system will be moving overhead in the Mid-Atlantic region leading to the possibility of lingering clouds and additional instability showers. Finally, by early Monday, the upper-level feature should exit the east coast and weaken allowing for the return of sunshine and warm temperatures as we begin the new work week.
Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com
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