As of 7am, a broad area of low pressure extends from central Wisconsin to south-central Ontario, with a minimum pressure near 1002 hPa. The surface warm front has slowly progressed north and is just north of NYC, while the cold front is near western PA and gradually tracking east.
As described in yesterday’s post, a mid level SSW wind over the last 1-2 days advected a warm and very moist air mass into the region, with strong thunderstorms having developed over Virginia and North Carolina before continuing NNE. These storms then ran into the stable layer north of the warm front where colder, dense air was located near the surface with a low level easterly wind, forcing the warm and moist air mass to lift with a broad area of moderate to heavy rain affecting the area throughout the day, primarily from NYC and further west. The heaviest rainfall rates were observed in the evening and early overnight hours as a band of heavy rain continued to train along the central-northern NJ axis before shifting east towards 10pm-12am, with sustained rainfall rates over 1/4 to 1/2 inch per hour. The steady rain mostly ended around 12-2am, but with scattered showers having continued until about now. Some clearing of the cloud cover is expected later today with highs surging into the upper 60s to mid 70s.
Widespread rain totals of 2 to 4 inches were observed across the area, peaking around 4 to 5.5 inches in western Long Island, NYC and northeast New Jersey with a total of 5.43″ in LaGuardia airport and 5.36″ in Newark, NJ. Below are some additional rain totals across the area: