Note: A new poll has been opened for the potential scenario on 12/5 and whether it snows or not. Please vote your thoughts in the poll, which will close on Friday.
Today was a mainly sunny day across the area, with high temperatures peaking in the mid to upper 40s inland, upper 40s to lower 50s in the immediate NYC area, and in the mid to upper 40s in Long Island/S CT. This morning was a cold one across the area, with low temperatures as low as the mid to upper 10s inland due to radiational cooling. Temperatures are currently steadily droppping across the area, however with increased cloud cover expected for tonight, the low temperatures will take place early in the overnight hours with warmer temperatures by tomorrow morning.
Temperatures will continue to warm up through Wednesday, when they should peak in the upper 50s to lower 60s ahead of a storm that will produce heavy rain, thunderstorms, and very windy conditions. A much colder pattern will settle in behind this storm, and afterwards we may be looking at the first widespread snow event for the Mid Atlantic by Sunday through Monday.
Tomorrow will be a mostly cloudy day across the area with a SE wind expected. High temperatures will be in the lower 50s inland, lower to mid 50s for the north/west suburbs of NYC, mid 50s in NYC, and in the lower to mid 50s for Long Island/S CT.
Looking at the rest of the region, the Mid Atlantic should warm up, with southern/eastern Virginia reaching the mid to upper 60s. Rain is expected to start falling in Pennsylvania and western New York, however any rain will stay to the west of the area until Wednesday.
Tomorrow Night – Wednesday: Becoming Windy, Stormy
Cloudy skies are expected tomorrow night as the cold front produces heavy rainfall in Pennsylvania/New York, with an occasional shower possible late for the western and central parts of the area. As a warm air mass moves into the area, with 850 mb temperatures rising to near 10c, temperatures will rise overnight, reaching the mid to upper 50s across most of the area by Wednesday morning. Windy conditions are also expected to develop overnight, with gusts near/over 40 mph possible, being why a Wind Alert is in effect for the area.
On Wednesday, a line of heavy rain and thunderstorms, potentially strong/severe south of NYC with damaging wind gusts the main risk, will move through the area from west to east, affecting the western parts of the area in the morning/afternoon and the eastern parts of the area in the afternoon/evening. By the time that the rain ends, at least 1.5 to 2.5 inches of rain are possible inland, 1 to 2 inches in the immediate NYC area, and 3/4 to 1.5 inches in Long Island/S CT. More updates on this storm will be posted tomorrow, as well as a final rain map.
Thursday – Saturday: Colder, Breezy
The cold front will move through the area on Wednesday night, with a negatively tilted trough moving into the area for Thursday. This trough, unlike the previous ones we’ve seen this fall, is expected to settle in, with a strong -NAO present, leading to persistent chilly conditions and mostly cloudy skies. High temperatures in this time frame will be in the upper 30s to mid 40s, with lows in the lower 20s to lower 30s.
Saturday Night – Monday: Potential Snow Event For Mid Atlantic
Over the last several days, the potential for a storm on December 4-6 was mentioned. While the GFS model is still not showing this scenario, it is still having difficulties handling the pattern and will likely start to show the storm soon. We are looking at a clipper from the north central US that will be moving ESE, and with the strong cold over the NE US and the -NAO, will track to the south of the area. With plenty of cold air available, this storm will likely produce snow to its north, even in the central and northern Mid Atlantic, between Saturday night and Sunday night.
While there still some uncertainty with the timing and the track of the storm, it is likely that there will be a clipper, and its track could range from southern Virginia to near Washington DC. At this time, the models are showing the southern track, with the heaviest snowfall between Washington DC-Philadelphia, but there is still time for trending and is it possible that the storm trends further north. With the potential scenario mentioned above, snow is likely to fall in at least the central and northern Mid Atlantic on Sunday, potentially including the NYC area, which will generally be light but may accumulate up to several inches where the heaviest snow falls. At this time, the potential snow area labeled on the map to the top is from central Virginia to southern New England, though this range will likely become narrower as the storm enters the shorter range. Stay tuned for more details on this potential storm and how it may affect the area.
After the storm exits the region, there is increasing uncertainty, however it is likely that the storm will intensify offshore once it exits the region by Monday. It appears that with the -NAO in place, the storm could get a negative tilt offshore, and according to the ECMWF model, may try to move back NW towards New England. There is a lot of uncertainty about what happens with the storm though, so stay tuned for more details over the next few days.