Overview A rapidly intensifying and already powerful low pressure system currently sits over southwestern Pennsylvania with its latest central pressure reading at 29.14 inches. This storm will travel across the state over the next several hours and swing an intense cold front across the region this evening which will result in a dramatic plunge of temperatures later tonight. Damaging wind gusts of 50 mph or so are a real threat in this pattern and these excessive winds can occur during the passage of the frontal system and also in the cold air behind the front later tonight into tomorrow morning with scattered power outages possible. So far, NOAA has not posted any tornado watches for the Mid-Atlantic region, but that is still a possibility as the afternoon progresses. Farther north, an all-out blizzard is now occurring in places like Cleveland, OH, Buffalo and Rochester in New York State with heavy snow, strong winds, and even some thunder and these blizzard conditions will extend shortly to interior sections of New England where more than a foot of snow can accumulate by morning.
The frontal passage (5-9PM) Temperatures have spiked this afternoon to spring-like levels ahead of the approaching cold frontal system and a line of showers and embedded strong-to-severe thunderstorms along the front will move through the metro region between the hours of 5 and 9PM. This is a “fast-moving” and “narrow” line of showers and thunderstorms, but any one of these storms can produce brief heavy rainfall and damaging wind gusts of up to 50 mph or so. The cold frontal passage will definitely not end the threat for extreme wind gusts in the region.
“Post-frontal” weather for the rest of the night and Thursday Once the front moves through the area, winds will shift to a northwesterly direction and they will gust up to 50 mph or so during the rest of the night and right through Thursday morning. Temperatures will plunge from early evening levels near 60 degrees to late night values close to 20 degrees and there will be single digit wind chill values across the region by morning. Scattered snow showers are likely later tonight and, while little or no snow accumulations are expected, some icy spots can form as a result of the rapid drop in temperatures to below freezing levels. Temperatures tomorrow will be way below normal for this time of year throughout the region - despite the return of sunshine - likely holding below 30 degrees for highs. A quick rebound in temperatures will occur on Friday in the Mid-Atlantic region following a very cold (but calmer) Thursday night. Looking ahead, after a mild Saturday, colder air returns to the region early next week and there is even the threat for some accumulating snow later Sunday into Monday.