[notice]New 12/28: A probability of precipitation table has been added to the blog.[/notice]
A brief warm up is on the way for today as temperatures surge into the upper 40s for most locations and low 50s near NYC with mostly sunny skies. This warmth will be very short lived as a coastal low tracks up the coast, producing widespread heavy rain around or over an inch. Cold temperatures will be followed starting on Monday, with highs mostly in the upper 20s-low 30s through Thursday with the potential for late week snow.
<< December 26 | December 27 | December 28 >>
Friday, December 27 Observations:
Behind Thursday’s light precipitation event, a transient cold air mass quickly moved through the area, with partly sunny skies but with temperatures slightly warming up compared with Thursday, peaking in the upper 30s to low 40s across the area. The cold air mass already exited by the overnight hours, with temperatures failing to drop much after the daytime highs especially closer to NYC and the coast.
The highest temperature was 42 degrees in multiple locations, and the coolest high temperature was 36 degrees in Sussex, NJ.
Today – Sunday: Warm, Then Rainy
Following the departure of yesterday’s trough, a northern stream shortwave will enter the north central US with a surface low pressure developing over the northern Great Lakes, while a frontal boundary extending eastward will nearly stall over the northern Adirondacks into coastal Maine. This will allow for a southwesterly flow to spread across the region today with a high pressure positioned to the south, with mostly sunny skies and highs in the upper 40s for most locations and the low 50s near NYC and NE NJ.
This setup will lead to a coastal system tomorrow which will track up the coast and produce widespread heavy rain. Another shortwave currently over Texas will eject out of the southern US and track up the east coast as a surface low pressure forms along the coast, interacting with the northern stream but failing to phase while over the region. With the cold air bottled up north of the frontal boundary over northern New England, no cold air will be in place to allow for a widespread snowstorm, instead supporting moderate to heavy rain across most of the region with temperatures ranging from the mid 30s inland to the low 40s along the coast. As the low tracks into New England, however, more cold air will filter into the system, resulting in heavy wet snow developing over northern NY, VT and NH, and a colder snowstorm over Maine which will remain under a cold Canadian air mass in the lower levels.
For the NYC area, high temperatures are expected to peak around noon in the mid-upper 30s inland, upper 30s-low 40s in NYC, coastal CT and the north/west suburbs, and the low-mid 40s in Long Island. Temperatures will hold steady or slightly fall as rain begins to fall after at least 12-1pm, becoming heavy at times towards 3-7pm. Rain is expected to taper off from SW to NE between 10pm-12am. With the low tracking near the coast, the strongest winds will remain offshore, although breezy winds up to 10-20 mph sustained from the NE are possible in eastern Long Island. Rain totals of at least 3/4″ to 1″ are expected for NW NJ and SE NY, and 1″ to 1.5″ for the rest of the area.