UPDATE: Significant Winter Storm Aimed At The East Coast, Dangerous Cold Friday & Saturday

Good evening! 

Today has been yet another in an impressive stretch of days below-freezing across the majority of the Northeast! Conditions were mainly calm, with patches of mid to high level clouds racing from southwest to northeast due to a strong/developing jet stream over the Northeast. An area of high pressure has been quickly moving offshore, which has shifted winds to the south over portions of the Mid Atlantic and southern New England. This subtle change was enough to bring in temperatures in the middle to upper 20’s for most of the NYC metro area, with 30’s further to the south. As we head into the night, we expect cloud cover to gradually increase as the large area of low pressure over the western Atlantic Ocean begins to expand substantially to the west and ushers in some mid-lower level clouds. Southerly low level flow will keep conditions a bit warmer than the past few nights, but expect lows to stay in the lower to middle 20’s over the immediate NYC metro, with upper teens likely to the north and west. Things should stay dry for most of the area up until midnight, when some initial light to moderate snow may begin to nose into the southern portions of New Jersey and Pennsylvania.

QUICK LINKS: Latest Snowfall Forecast | Latest Video Discussion

This afternoons high-resolution visible satellite imagery, surface observations, and regional radar showing a mostly sunny day across the Northeast with some occasional spots of clouds

Significant Winter Storm Tomorrow

The area of low pressure that we have been tracking for the better part of a week now is finally getting its act together across portions of the Southeast United Sates this evening. Model guidance over the past few days has largely corrected to the west and has also stepped up with precipitation on the western side of the low pressure system after showing solution way down over Bermuda. This system has been an extremely difficult system to track given all of the complex individual pieces that had to come together to even get a storm to form. Additionally, all of the high resolution models show an enormous amount of convection developing with this low during the overnight hours tonight that will cause the surface low pressures to drop quite significantly. These pressure falls are on the order of 30-40 mb in just 24 hours, and meet the criteria for “explosive deepening”. Regardless of the ominous terminology, we should start to see more precipitation form over portions of the Mid Atlantic this evening in response to a very favorable and expanding upper level jet stream to the north of this system. This precipitation should move into the Northeast around 3-5am, but the initial dry conditions over the Mid Atlantic and Northeast may prevent any snow from reaching the ground for a few hours.

This afternoons hi-res NAM model showing a simulated radar depiction for 8am tomorrow morning. The deeper blues represent moderate to heavy snow (credit: Tomer Burg)

Once the atmosphere begins to rapidly moisten as the low draws closer, light snow will continue to develop from the south and gradually increase in intensity and coverage over the Mid Atlantic states and Northeast, becoming moderate to heavy over most locations by 6am-8am. By tomorrow morning, our system should be due east of the Delmarva peninsula, with relatively widespread snow of varying intensity from Virginia to Massachusetts. Pressures with this low pressure system will likely be in the 960’s by the late morning hours, which should cause winds to increase quite a bit over the entire East Coast. We may see some initial bands of moderate to heavy snow form over eastern Pennsylvania and New Jersey tomorrow morning, but these bands should gradually sink to the south and east as we head into the afternoon hours. Snowfall rates should be at their heaviest at around 11am-2pm across coastal New Jersey and Long Island, with some areas possibly seeing rates approach 2″/hr in some of the more concentrated banding. Conditions will become quite hazardous for travel as moderate to heavy snow and strong, gusty winds will greatly reduce visibilities. For this reason, the NWS has issued numerous Blizzard Warnings from North Carolina to Northern Maine.

Map of all Blizzard Warnings (Orange) Winter Storm Warnings (Pink) and Winter Weather Advisories (Purple) across the Northeast this evening

Snow should begin to gradually wind down from southwest to northeast during the afternoon hours, with eastern locations likely staying in oscillating bands of moderate snow until the early evening hours. Since models have trended westward with the precipitation shield, we have made some adjustments to our snowfall map, but the general theme remains the same. This should be a relatively short-duration and high-impact system with some areas only seeing snow for 6-12 hours. Regardless, the impacts will be significant for tomorrows commute and travel is highly discouraged during the afternoon hours.

Storm Total Snowfall Forecast:

Storm Total Snowfall Forecast

VIDEO UPDATE:

Brutal Cold Friday and Saturday 

A pure Arctic airmass looks to blast down south and into the East during the day on Friday with strong northwesterly winds accompanying it. Temperatures across the entire Northeast will be much-below normal, with highs struggling to get out of the low-teens and single-digits over the entire region on both days. Lows will also be seriously cold, with readings likely hovering in the 0-5 range in the NYC metro area, with locations to the north and west seeing temperatures below five to ten degrees below zero. The real dangerous part of both days will be with the wind chills, which can potentially reach -15 to -20 degrees at their peak on Saturday morning. Exposure to these kinds of temperatures will lead to frostbite very quickly, so you will absolutely need to layer-up if you have to go outside during the morning hours. Additionally, do not leave pets outdoors and keep their time outside at an absolute minimum as they too can experience the effects of frostbite.

Otherwise, we are looking at a another system to effect the East early next week, but details are not clear at this time, with a wide variety of solutions possible. We’ll have details on that system later in the week!

This afternoons ECMWF model showing a deep Arctic airmass set to move in directly behind Thursday storm!

Have a great evening and stay warm!