11:45 AM (Tuesday) | **Snow showers possible on Wednesday in the Mid-Atlantic/NE US…best chance in areas near and north of the PA/MD border**
Paul Dorian
An unstable atmosphere is coming to the Mid-Atlantic region and Northeast US on Wednesday as a surface cold front arrives supported by a powerful jet streak at 250 millibars and a potent wave of energy at the 500 millibar level. Map courtesy NOAA, tropicaltidbits.com
Overview
A cold front will arrive in the Mid-Atlantic region on Wednesday and it will be accompanied by a strong wave of energy in the upper part of the atmosphere and a powerful jet streak. As a result, snow showers can break out on Wednesday; primarily, in areas near and to the north of the PA/MD border region, and there is even the chance for small accumulations in some spots. High pressure resumes control of the weather for the latter part of the work week.
An unstable atmosphere is coming to the Mid-Atlantic region and Northeast US on Wednesday as a surface cold front arrives supported aloft by a strong wave of energy at 500 mb (i.e., vorticity center) and a powerful jet streak at 250 millibars. Map courtesy NOAA, tropicaltidbits.com
Details
A potent wave of energy in the upper part of the atmosphere will push into the Northeast US on Wednesday and it will be accompanied by a powerful jet streak at the 250 millibar level (~10,000 meters) and a strong northwest-to-southeast moving surface cold front. As a result, there will be some strong upward motion mainly in areas near and north of the PA/MD border. Consequently, snow showers are likely to break out in these areas - perhaps even as far south as the northern suburbs of DC - and there can even be small accumulations in some spots - watch for slick spots on the roadways. Late tomorrow, it’ll stay on the chilly side, but sunshine is likely to return to the Mid-Atlantic region as the surface cold front sweeps off the east coast.
12Z NAM surface forecast map at noon on Wednesday depicts some snow bands in the Mid-Atlantic/NE US (in blue) and there can even be some small snow accumulations; primarily, in areas near and north of the PA/MD border. Map courtesy NOAA, tropicaltidbits.com
Looking ahead, high pressure will take control of the weather in the Mid-Atlantic region on Thursday and Friday and its shift to a position off the eastern seaboard at week’s end will lead to a noticeably milder weekend. The weekend warm up in the Mid-Atlantic region is likely to be accompanied by some shower activity ahead of the next approaching strong cold front with high temperatures well up in the 50’s on both weekend days in the DC-to-Philly-to-NYC corridor. Following the passage of the weekend cold front, a colder air mass will push into the region on Sunday night and Monday and highs will likely fall to slightly below-normal levels for this time of year (normal high now at PHL is 48 degrees, 49 degrees at DCA, and 46 degrees in Central Park, NY). There is also the threat that low pressure develops near the east coast in the early or middle portions of next week which is something we’ll have to closely monitor in coming days.
Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com
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