11:45 AM (Thursday) | ***Powerful and potentially damaging wind gusts of 50-60 mph later tomorrow/tomorrow night***
Paul Dorian
Strong winds in the upper atmosphere on Friday/Friday night will contribute to a high wind event for the Mid-Atlantic region which could feature gusts at surface-level in the 50-60 mph range. Map courtesy NOAA, tropicaltidbits.com
Overview
The current warm spell in the Mid-Atlantic region that peaked on Wednesday afternoon will come to a halt with the passage of a strong cold frontal system in the early morning hours on Friday. A cooler air mass will arrive in the region on Friday and temperatures later tomorrow night will drop significantly into the lower 40’s for overnight lows – a far cry from the mid and upper 80’s experienced yesterday afternoon. While the cool down will be quite dramatic from the summer-like warmth on Wednesday, the bigger story will be the winds which could gust to the 50-60 mph range later tomorrow and tomorrow night – potentially resulting in downed limbs and scattered power outages.
Another important contributing factor on Friday/Friday night to the high wind event in the Mid-Atlantic region will be intense pressure gradient between departing strong and intensifying low pressure and an approaching strong high pressure system. Map courtesy NOAA, tropicaltidbits.com
Details
Showers are likely this afternoon and evening in much of the Mid-Atlantic region as a cold frontal system just to the north features a couple of waves of low pressure that will ride along its boundary zone. There can even be an embedded strong-to-severe thunderstorm this afternoon or evening in the I-95 corridor region as this front gradually slides to the south and east. A stronger cold front over the Northern Plains will actually become the dominate system later tonight as it slides through the region bringing an end to the threat of showers and thunderstorms. It is this second front that will usher in a cooler air mass for the end of the work week and beginning of the upcoming weekend.
For this afternoon and evening, showers will be in the Mid-Atlantic region and there can be an embedded strong-to-severe thunderstorm as well. Images courtesy NOAA, College of DuPage
On Friday, a jet streak associated with an upper-level trough will approach the Mid-Atlantic region from the Great Lakes. Meanwhile, at the surface level, low pressure will intensify rapidly as it passes just to the east of the New England coastline on Friday at the same time high pressure builds to our north and west. The pressure gradient will tighten dramatically later tomorrow between the departing strong and intensifying low pressure system and the approaching strong high pressure system and this will result in strengthening winds at ground level. Winds are likely to start the day on Friday in the 15-20 mph range from a westerly direction with gusts to 30+ mph, but they will likely increase substantially as the day progresses with height falls aloft and cold advection that will support mixing. The overall atmosphere will become quite unstable as the day progresses on Friday with very steep lapse rates – all of which will contribute to wind gusts in the 50-60 mph range later tomorrow and tomorrow night. The likely 12-hour time period for the worst of the wind gusts is from around 2 or 3 PM on Friday to about 2 or 3 AM on Saturday. Downed tree limbs is on the table with the potential of 50-60 mph wind gusts; especially, considering the fact that leaves are now pretty fully grown. Unfortunately, power outages are also on the table for this potential high wind event from later tomorrow into early Saturday in the Mid-Atlantic region.
As the pressure gradient relaxes on Saturday, winds should die down noticeably as well as the day progresses and temperatures will likely rebound from the 40’s early in the day to the 60’s later in the day. An even warmer day is in store for Sunday with temperatures likely to flirt with the 80 degree mark for afternoon highs in at least parts of the I-95 corridor.
Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com
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