8:45 AM (Sat.) | ***Severe thunderstorm threat in the Mid-Atlantic region later this afternoon into tonight with strong cold front…higher risk of severe weather in DC and Philly…lower in NYC*** — Arcfield Weather

Showers and thunderstorms have already formed over eastern Ohio and West Virginia this morning and they will work their way eastward during the next several hours. As the upward motion increases in the atmosphere and daytime heating intensifies, the atmosphere will become more and more unstable and some the thunderstorms will likely intensify into strong-to-severe levels. Given the strong low-level jet that is expected to form near the frontal boundary zone, strong and potentially damaging wind gusts will likely become a threat with a line of thunderstorms likely to form later in the day.  In addition, some signs point to a “backing” of surface flow later in the day and this may allow for a “spin” in the atmosphere to develop as a line of thunderstorms approaches.  This could result in a few isolated tornadoes as the storms move through with perhaps the greatest risks in SE PA and the Delmarva Peninsula. The threat for the active weather will begin in the early-to-mid afternoon hours in the DC metro region and mid-to-late afternoon near Philly. While there can be strong storms in and around the NYC metro region, the risk for severe weather is lower than in places farther to its south and west such as DC and Philly as cooler, marine air up there will keep the atmosphere more stable.

In terms of rainfall, this frontal passage will actually bring some much needed amounts of generally 0.50-1.00 inches although locally higher amounts are possible in any strong thunderstorm.  Temperatures today will climb into the 70’s ahead of the cold front and will be confined to the 60’s on Sunday for afternoon highs and then it’ll turn even cooler on Monday following the passage of a secondary cold front on Sunday night.

Meteorologist Paul Dorian
Arcfield
arcfieldweather.com

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