Conditions have improved substantially across much of the Northeast this Friday afternoon as a rather weak cold front cleared out any remaining cloudy & unsettled conditions.
The beautiful spring-like conditions of the past two days have quickly come to an end, and have instead been replaced with a cool and rather unsettled pattern.
The periphery of a piece of the polar vortex (an important distinction) made its presence felt in the New York City area on Wednesday and Thursday, with intense snow squalls and bitter cold temperatures. The low temperature in New York City dropped to 2 F on Thursday morning, the coldest of the season thus far and the coldest since February of 2016.
The airmass will remain bitterly cold over the next 24-36 hours, as arctic air remains overhead. It will begin to shift out of the region by the weekend, however, and the airmass will feel downright tropical by the time we approach Saturday. High temperatures will swing back towards normal by that time, a far cry from the 30 or more degrees below normal which we’ve been basking in.
The line of heavy snow squalls that we talked about back on Monday blasted their way through portions of the Northeast earlier this afternoon. These squalls produced a quick burst of very heavy snow and strong, gusty winds that created significantly reduced visibility to just a few feet in some locations. Numerous accidents were reported across Pennsylvania, New Jersey, and New York, with a large incident involving over 40 cars in Berks County, Pennsylvania. The squalls have since moved over the far eastern portions of Long Island and will continue to head quickly to the east before moving offshore.
The main story for this entire forecast period remains to be the long-awaited Arctic front associated with the tropospheric Polar Vortex . This front will move through the New York City metro area later this evening and into the overnight hours, causing temperatures to rapidly fall. Readings will fall into the teens for the entire area this evening before falling once more into the single digits overnight-with locations off to the north and west likely getting below zero! Winds will also be quite strong behind this Arctic front, with sustained winds of around 20 mph and gusts up to 45 mph. The combination of extremely cold low temperatures and strong winds will make for some dangerous wind chills tonight. Wind chill values of -10 to -15 will be quite common for the entire forecast area, with values as low as -20 to -25 for elevated locations of NW NJ!
NWS forecasted lows valid 7 AM Thursday. The circles show the potential for records to possibly be broken (WxBell)
Thursday morning will likely start off as the coldest day of the season, with temperatures in the single digits for the AM commute. High temperatures will gradually crawl back into the teens for most of the area with clear skies overhead, but wind chills will continue to make things feel more like -5F to -15F. High pressure will be building to our south during the afternoon hours tomorrow, allowing winds to gradually ease-off as we go deeper into the day. Deep northwesterly flow will continue to bring in a very dry, stable airmass over much of the Northeast leading to persistently clear skies into the evening hours. The deep “vortex” located off to our north will be gradually moving well to our north and east throughout the day tomorrow, leaving a very cold, but slightly modified airmass in place for tomorrow night. Lows will once again drop into the low teens to single digits across much of the area, which will still be well-below normal for this time of year.
Cold, calm, and clear conditions will extend into Friday as high pressure builds over the East. We may have to watch a very weak shortwave trough near the Great Lakes that will be rapidly moving to the south and east during the day. An area of light snow may break out over portions of the Mid-Atlantic on Friday afternoon, but this is expected to stay to the south of the NYC metro area-with only some increased clouds expected for our area. Highs on Friday won’t be as brutal as Thursday, with lower to middle 20’s expected for the NYC metro, and teens likely off to the north and west. Lows will fall back into the teens to single digits once again on Friday night, making for a rather cold end to the week.
Loop of the high resolution NAM model showing the progression of dangerously cold temperatures through Thursday
A significant warm-up seems to be in the cards as early as Monday/Tuesday as another storm system off to our west cuts into the Northern Plains. Like the numerous storm systems that have done so this winter, this system will cause deep southwesterly flow to overspread the area. This will bring a return to highs in the lower to middle 40’s as early as Monday, with highs possibly getting into the 50’s by Tuesday!
The “warmer” pattern will be in place at least through the middle of next week as yet another strong Pacific disturbance carves out a trough in the West, leading to a large area of mid level ridging over the East Coast. At this time it appears that the threat of any major precipitation events are quite low, but there are some indications that conditions will turn wet by Wednesday/Thursday with another system cutting well off to our north and west.
This afternoon’s ECMWF run showing a deep trough located over the west and building ridge over the East. Such a pattern would favor a return to above average temperatures in the East
We’ll have an update on Friday taking a look at this weekend!
Have a great night
-Steve Copertino