Good evening! Despite the dreary weather, we hope you had a good day! An onshore flow with low-level moisture underneath inversion will likely continue to keep mostly cloudy skies into tonight. Temperatures this evening will likely remain steady in upper 50s to lower 60s. A few more scattered showers are possible through the evening, as frontal boundary continues to approach. But stronger thunderstorms over central parts of New York and Pennsylvania should weaken and fall apart as the move into a more stable marine airmass over the region. Temperatures with the cloud cover will not likely drop out of the 50s overnight, over most of the region.
Mostly cloudy skies are still likely for the beginning of the rush hour tomorrow morning. Some areas patchy fog and drizzle could also be around. But more southerly flow ahead of cold front associated with shortwave through, should allow clouds to break for more sunshine during the afternoon hours. This sunshine along with more southerly winds, will help temperatures will rise into the lower to middle 70s, tomorrow afternoon for highs. The only exception is along the coast, where more marine influence, from the southerly winds off the ocean will keep temperatures in the mid-upper 60s.
Some scattered showers and thunderstorms are possible, ahead of the cold front tomorrow afternoon. Strong winds fields and colder 500mb temperatures will enhance shear and lapse rates with this system. A few models are indicating moderate instability with MLCAPE between 500 to 1500 J/kg and mid-level lapse over around 6.0 to 7.0 C/km and strong 0-6km bulk shear between 40 to 50kts. These will support some isolated strong to severe thunderstorms with gusty winds and large hail, especially with more distance northwest of NYC. Thunderstorms likely be weakening as they run into a more stable marine airmass, likely near the coast.
Any showers or thunderstorms will come to end later tomorrow evening, as the cold front moves through. Temperatures will drop into the mid-upper 50s to near 60 during overnight hours Wednesday. Then high pressure builds into the region with more pleasant, mostly sunny weather on Thursday. West-northwest downslope winds and deep mixing in the atmosphere will help temperatures rise back into lower to middle 50s. Thursday night Friday will see much of the same with temperatures in lower to middle 70s with more west-southwest winds. There is a slight chance of a few isolated showers and thunderstorms popping over parts of the Lower Hudson Valley and Connecticut, as a frontal boundary from the north begins moving slowly to the south.
But more unsettled and wetter weather is likely over the weekend into early next week, as the frontal boundary will be moving slowly to the south. Shortwave energy rounding an larger upper-level low over Southeast Canada will lead to development of couple of waves of low pressure running along the frontal boundary. These waves could bring more significant rainfall or showers and thunderstorms, if we the region is still in a warmer, unstable airmass. But it’s too early, no what timing of each wave will be and how much rainfall they will bring to the region. It does look it will be trending cooler than normal by Sunday and Monday, as the frontal boundary push south of the region.
So while some warmer, drier times are ahead for late week, you may need to the jackets and umbrellas again by late the weekend. So continue to look for more zone forecast or other updates here over next few days on the threat for some strong thunderstorms on Wednesday and more unsettled weather coming by this weekend!