A few showers for the coast Thursday; interior snow likely to start the weekend

Forecast for Thursday into Friday morning

NAM model precipitation forecast 8 PM Wednesday to 8 PM Thursday

Clouds generated during Wednesday hang around for the overnight for most areas outside of the Allagash region. The coastal plain may pick up a light shower through early Thursday morning, but rain amounts are expected to be very low. Lows to start Thursday will be in the upper 20s for the far northwestern part of Aroostook, 30s to near 40° elsewhere.

Thursday starts off with varying amounts of clouds early, perhaps some clearing for a time with clouds on the increase through the afternoon. High temperatures range in the 50s for most, 60° possible for interior southwestern areas. Shorelines deal with the seabreeze which may pop a brief light shower in the afternoon.  

NAM model precipitation forecast 8 PM Thursday to 11 AM Friday

A cold front passes through the region Thursday night into Friday morning. The mountains could see some snow shower activity, with a chance for a shower elsewhere. Overnight lows range from the upper 20s in the mountains, 30s for most, with 40° possible along the coast. 

This cold front is one of the key table setters for the storm that impacts the region Friday night into Saturday.

Heavy, wet snow to impact interior areas
​to start the weekend

Right out the gate I will forewarn you that the track is not nailed down as of yet. As the Euro ensemble run above indicates there is some uncertainty with track and timing. Since the event kicks into gear Friday night into early Saturday, what happens in darkness will be key. 

European model 1 hour precipitation / sea level pressure forecast 2 PM Friday to 2 AM Sunday

The operational / deterministic models for the most part are indicating a coastal hugger at this point, but ensembles are bit further offshore, which creates some of the uncertainty. While the mountains are likely to get the higher snowfall totals, who gets how much elsewhere depends on the timing and track. There is plenty of moisture to work with here as this has a Gulf of Mexico hose attached to it. The upper level pieces I discussed here yesterday (driver / kicker) appear to come together during the day on Saturday. By the time the storm gets to Maine Friday night, it appears to be in early development stage and then will mature as it moves eastward into the Canadian Maritimes Saturday afternoon. This means while the region gets some impacts, the bigger threat is for our neighbors to the east. 

My first call on snowfall shows the heavier amounts over the interior. A few things to keep in mind here. This is May. The sun angle is high, which helps warm the atmosphere. We are dealing with some deep anomalous cold, however. There will be records shattered for recorded temperatures in the sky above. Most of the snow from the season is gone, and soil temperatures have warmed up, so snow will melt.

The concern I have is with "the thump" to come, especially over interior areas where hourly snowfall rates could be 1-1.5" per hour. Ground temperature does not matter in that case.  This will cause snow covered roads and slick spots. 

With tropical hose, there is always the chance for thunder to come along with it.  

The storm will intensify, and with that,  comes wind.  Places that see snow stick to everything will need to be concerned with power outages. Fortunately with this painfully slow, cold spring going on, the foliage has not developed on trees, which helps reduce the power loss potential somewhat.  That said, interior areas should keep supplies on the ready in case disruption of power occurs. 

Shovelling of this storm is optional. 

Storm aftermath

Sunday appears to be on the breezy side as the storm slowly moves eastward. The wind starts off in the northwest then shifts west by afternoon, and settles down toward evening. Temperatures range in the mid to upper 30s where there is snowpack, 40s for most with perhaps 50s for interior York County. The wind chill is different story with 20s for snowpack regions 30s/40s elsewhere. The cooler than normal trend continues into next week as it appears for now. 

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​► ► For the latest official forecasts, bulletins and advisories, please check in with the National Weather Service in Gray for western and southern areas, or Caribou for northern and eastern parts of Maine.

Thanks as always for your support!

​- Mike