0z NAM simulated radar for this evening

Rain Likely Today…Colder Weather Arriving This Weekend

Today will be a dreary day. This morning will start with some clouds, fog, and a few light showers around. Then periods of steadier rain will arrive with a cold front this afternoon and evening. Model guidance shows a strengthening southeasterly low-level jet between 40kt-50kts and high precipitable water values over 1.30″, indicating high atmospheric moisture content. This will likely result in rainfall being heavy at times this afternoon and evening.

Model guidance shows little instability. But an isolated thunderstorm can’t be ruled out, considering the warm air advection and forced ascent occurring. Rainfall totals of 1″ – 2″ of are possible in parts of the region. The upslope flow with southeast winds could help enhance rainfall totals over higher elevations north and west of New York City as well. The stronger winds aloft are not expected to mix down to the surface; however, with a tightening pressure gradient, winds could gust in excess of 30mph in spots — especially near the shore or with any isolated thunderstorm.

0z GFS showing high precipitable water values over 1.40"

00z GFS showing high precipitable water values over 1.30″

We will also be in the warm sector later today and tonight thanks to a strong southeasterly flow. 850mb temperatures will rise to between 10°C and 12°C, with warm air advection increasing during the evening hours.  This will lead to surface temperatures rising into the lower to middle 60s.

Friday will be turning colder, with skies clearing for some sunshine. Temperatures will be dropping through the 50s and 40s. Friday night will be chilly with temperatures dropping into middle to upper 30s for New York City and coastal sections, with lower to middle 30s likely for many of the inland areas.

A colder trend continues over the weekend with high temperatures in middle to upper 40s on Saturday with mostly sunny skies. Low pressure tracking into the Great Lakes will send another cold front through the region on Saturday night. Some widely scattered showers are possible with the front. A southwest flow ahead of this front could cause temperatures to rise into the 50s briefly Saturday night.

GFS 2m temperatures for 7am Monday morning

GFS 2m temperatures for 7am Monday morning

Behind this front is an even colder airmass. Sunday will likely be breezy with temperatures holding steady in the 40s for much of the day. As colder air continues filtering into the region, Sunday night could be the coldest night of the season so far. 850mb temps will drop below -10°C Sunday night. Many inland sections and pine barrens are likely to fall below freezing, with possible lows ranging from the middle to upper 20s. Temperatures could fall into the lower to middle 30s in New York City and coastal areas.

A large trough digging into the Western US should cause a ridge to gradually build into the Northeast US later next week. A moderating trend in temperatures should thus ensue with fair weather. High temperatures will be back into the lower to middle 50s for highs Tuesday with plenty of sunshine. At this time, it appears the big travel days of the week — Wednesday and Thanksgiving Day — will be dry with high temperatures in the lower to middle 50s again.