Last night we witnessed the greatest comeback in Superbowl history and over the next 7 days we’re likely to witness a robust comeback in terms of winter weather. An icy storm will bring snow, sleet, and ice to the region tonight through Wednesday. This will be quickly followed by a storm threat for Thursday as colder air pours into the region. Lighter snow is forecast for Saturday before another mess takes shape late in the day Sunday into Monday. Welcome back to winter!
Seeing as we have many storms in the forecast and I’d like to get this done by midnight, the analysis for each storm won’t be as beautifully detailed as I might like. Hopefully we can pull a snowday out of the hat tomorrow for more detailed coverage.
Mess #1- Tonight Through Wednesday Morning
A weak upper level disturbance will approach tonight and in advance of it, snow will break out. There’s lots of dry air for this system to overcome and so I don’t expect much snow to actually make it to the ground until later this evening for NH and later tonight/early tomorrow morning for Maine. Snow will continue through tomorrow before changing to sleet/freezing rain tomorrow night and into Wednesday morning. Expect right around an inch on the ground by the time the commute arrives tomorrow morning.
Light to moderate snow will be the rule for most of tomorrow as warm air moves up and over the cold air near the surface. The main low pressure system will track well to our west though a secondary wave of low pressure will develop along a bump in the warm front near Cape Cod. This will keep those NNE winds going strong keeping cold air locked in place at the surface. As the warm air advection aloft intensifies, precip will too. We’ve already gone over how heavier precip keeps cold air in place due to latent heat transfer from phase changes (melting precip cools air as snowflakes require energy to move from solid to liquid state) however strong WAA will eventually overcome this process aloft changing precip over to sleet and freezing rain.
As evening approaches tomorrow so too will warm air in the mid levels of the atmosphere. This cross section from VA (left) to NB (right) goes right through Maine (middle/right) and shows a cold frontal surface to facilitate overrunning precip tomorrow as well as a change to mixed precip tomorrow night. Warm air being forced up and over this low level cold dome will give us the snow tomorrow and the warmth eventually becomes warm enough to melt the snow into sleet and freezing rain.
Here’s what the result of that process looks like early Wednesday morning. Notice the warmth aloft has made it well north into Canada and a secondary low pressure system off Portland is locking in the cold at the surface. As a result, look for an icy mix to last into the morning commute Wednesday even along much of the coastline. The exception will be in the usual spots along the midcoast where the secondary low could mix up the atmosphere enough to draw down some of the warmer air aloft.
The event ends Wednesday with a temperature roller coaster along with slick travel for the morning commute. As the deeper moisture and best dynamics lift off to the NE. we’ll be left with freezing drizzle for the morning commute Wednesday. Temps will rapidly jump up into the 50’s for a few hours around noon Wednesday for most (possibly excluding the northern mountains) as the warm front lifts north and the cold air dam mixes out. The cold front will put a quick end to the spring like temps Wednesday evening as temps will quickly drop back below freezing. The refreezing of any water/slush on Wednesday evening will be something to watch as a potential hazard for the Wednesday evening commute and/or the Thursday morning commute. Black ice will be something to watch for in that timeframe.
Our next storm will develop right on the heels of our Tuesday-Wednesday mess. The cold front that will put an end to our brief few hours of spring weather will stall out over the Mid Atlantic and incoming Pacific energy will form a storm along the front Wednesday evening. Exact interactions between all the various disturbances will determine if that storm intensifies up the coast resulting in a sizeable snow storm or if it zooms harmlessly out to sea. Right now, I’d lean towards a light/moderate snow event beginning Thursday morning and ending Thursday evening. The best chance for several inches of snow will be along the coast though even there, dustings could be the upper limit if the storm tracks a little farther out to sea.
Looking past Thursday, a light snow event is in the works for Saturday with another messier system for Sunday night into Monday. More details on those as we go through the week.