We hope everyone had a great Thanksgiving! Today provided a chilly day for all of the Black Friday shoppers, though the airmass will be moderating over the next few days, before a cold front swings through on Monday night.
Tonight will be very chilly as high pressure slides just to our south tonight. With clear skies and diminishing winds, temperatures will fall pretty quickly tonight via radiational cooling. Clouds may increase a bit as we head closer to daybreak — particularly to the west of NYC — but that won’t be before temperatures generally fall to around 20 in most NYC suburbs, mid teens in snow-covered NW regions, and low-to mid 20s in NYC itself.
As we head to Saturday, the airmass will be modifying pretty quickly, as 850mb temperatures rise. This is because the high pressure will be moving to our east, giving us a return SW flow an an approaching warm front. However, the warm front will lead to an increase in clouds, which will prevent surface temperatures from rising much. Highs will be in the upper 30s, with the chance of some light snow showers and snow flurries — perhaps mixing with rain showers closer to the immediate coast. There is not a lot of lifting with the front, so precipitation will be spotty and not heavy — and any snow should not accumulate.
On Saturday night, temperatures will hold steady in the 30s, and may even rise to the low 40s, due to the continued cloud cover and SW winds. Temperatures aloft will continue to warm to above freezing, so any lingering precipitation should be in the form of drizzle, with perhaps some freezing drizzle in elevated areas NW of NYC. Some patchy fog may be developing as well.
The warm front will cross the area before daybreak on Sunday, and then lift well to our north during the day, which may allow for clouds to decrease. This means we may be able to translate the warmer temperatures aloft down to the surface, with high temperatures in the upper 40s to low 50s. Clouds won’t be able to completely clear because a cold frontal system will be close-by, but will not cross until Monday.
This means that Monday — before the cold front crosses — temperatures should warm into the low 50s, before rain arrives during the afternoon. it does not look to be terribly heavy as of now. Once the cold front crosses, an Arctic High pressure will be building in, leading to temperatures falling back into the 20s on Monday night and holding into the 30s on Tuesday. There is a chance that energy will linger behind the cold front, giving the area some rain and snow showers on Monday night. The core of the cold will end up staying just to our north, as parts of northern New England may fall into the single digits on Monday night.
As a whole, the weather pattern will be variable and nothing will sustain itself. We have a fast flow in the Pacific, blasting most of the US with Pacific air, instead of Arctic air. However, we do have plenty of cold air bottled up in Canada, so when that cold air combines with warm air further south in the US, some weak disturbances can be generated. Those disturbances will generally move to our north, giving us southerly winds out ahead of them and rain showers, but considering how cold it will be in Canada, the trailing cold fronts will have access to very cold air, giving us a day or two of cold as well. Overall, though, warmth should win out to start the month of December, but not significantly so; moderate warmth will generally rule but be interrupted by a couple of days of chillier weather.