Behind this morning’s light snow event, which produced totals locally up to 1-2 inches northeast of NYC, a strong cold air mass entered the region with the coldest temperatures so far this fall with widespread low temperatures below 30 degrees and localized lows below 20 degrees inland. Chilly temperatures will continue into Wednesday, but with a quick late week warming trend as high temperatures return into the 50s and 60s by the weekend and early next week ahead of the next rain event (Image credit: PSU e-Wall).
Tonight – Saturday: Cold Start, Then Warming Up
A cold front moved through the area late last night, but with most of the precipitation falling behind the surface cold front. With a much colder air mass entering the region, temperatures were cold enough to support a changeover to snow across the area this morning, resulting in the first widespread snow event of the winter. Most of the snow was focused over Long Island and Connecticut where minor accumulations up to 1/2 inch were generally reported, locally higher in parts of southern CT with a report of 2.0 inches in Ridgefield, CT (Fairfield county).
The core of the cold air mass is currently centered over the region, with 850 millibar temperatures near the -10C to -14C range. A steady northwest wind at 4-8 mph is expected to continue tonight with a pressure gradient in place and continued cold air advection, although mostly clear skies are expected which should allow for cold temperatures, with temperatures falling into the upper 20s-low 30s in NYC, low-mid 20s in the north/west suburbs, southern CT and Long Island, and the upper 10s for interior NE NJ/SE NY and higher elevations of CT. Locations that have yet to experience sub-freezing temperatures are expected to reach and fall below 32 degrees tonight. Mostly sunny skies are expected on Wednesday with highs struggling to warm above the mid to upper 30s.
The cold air mass will be quickly removed from the region, however, as ridging aloft builds into the region as more persistent lower heights set up over the western half of the US, along with the strong surface high pressure extending south of the area, setting up for a west-SW flow which will quickly bring a much warmer air mass into the region with 850mb temperatures reaching the 6-8C range. After another cold night with widespread lows in the 20s, temperatures on Thursday will warm into the mid to upper 40s with mostly sunny skies, and the low to mid 50s on Friday, returning closer to average. An increase in cloud cover is likely starting on Saturday with highs reaching the mid to upper 50s range, perhaps near 60 degrees in NYC and northeast NJ.