These days, Spring’s impacts are fleeting at best. This week won’t be much different, as Spring will make a one day appearance on Thursday and disappear for several more days thereafter. Nevertheless, the impacts over the next 24 to 48 hours will be noteworthy when it comes to our sensible weather. A warm front approaching the area will be first signaled this afternoon by steady showers, which will continue on and off through the evening. Temperatures will rise into the 40’s as winds turn southerly from the late afternoon into the overnight period.
A low pressure system developing from the Ohio Valley into the Northern Mid Atlantic will aid in the continuation of the aforementioned southerly flow on Thursday. The approaching warm front will continue the chance of showers, with clouds and fog likely in the morning hours. Temperatures, however, will rebound into the 50’s during the day. The warm front will also be home to a tremendous thermal gradient, which will shift northward through New Jersey toward New York City on Thursday.
This thermal gradient, along the warm front, will serve as a sharp boundary between Spring like conditions and dreary, late wintry ones. Temperatures across parts of Southern and Central New Jersey could exceed 60 degrees in the warm sector (area south of the warm front but ahead of the cold front) on Thursday afternoon, while places north of the warm front are stuck in clouds and drizzle. Where the warm front sets up will obviously have impacts on the forecast — but most models currently keep it just south and west of New York City.
Not surprisingly, the threat for thunderstorms will exist on Thursday. With the warm front pushing north, increasingly moist air will come with it, aiding in the development of some atmospheric instability. Favorable atmospheric dynamics could also allow updrafts to organize from showers into thunderstorms during the afternoon. These storms will be possible both along and near the warm front Thursday afternoon, and again along the cold front Thursday Night.
While strong to severe thunderstorms aren’t likely, a few isolated thunderstorms with heavy rain and gusty winds are possible. These are most likely to occur from Southeast Pennsylvania into Central New Jersey, where the most favorable juxtaposition of instability and dynamics exists Thursday afternoon and evening. Farther north, thunder should be more isolated while showers will remain more steady.
Regardless of who gets over 60 degrees and who doesn’t, these temperatures will be fleeting. The cold front associated with the storm system shifts east through the area early on Friday, bringing a return of colder than normal air for the weekend. Precipitation may even end with some snow flakes on Friday after the cold front passes by.