The forecast for Wednesday into Thursday remains on track this evening. As it is drawing nearer, I’ll elaborate a little on the expected impacts which include snow, sleet, freezing rain/ice, heavy rain, and wind. I’ll do a quick rundown of each threat. All in all, this will be a fairly typical inland runner and nothing out of the ordinary is expected for Maine. One wave of precip will arrive during the day Wednesday into Wednesday night while the second will arrive Thursday morning and continue through Thursday afternoon. A third wave is likely following that which will last into early Friday morning.
Wave One: Snow
Ahead of the storm, we have fairly cold air (step outside if you don’t believe me). As per usual, cold air leaves when it pleases and as warm air begins to move north, the first phase of the fight will feature snow Wednesday morning. A general 1-3″ is expected before warm air aloft moves in to turn things over to sleet and freezing rain. A bit more is expected in the mountains where I could see 2-4″. I also wouldn’t be surprised if coastal areas only saw a coating. This will fall overnight tomorrow into the early morning hours Wednesday. As dawn breaks Wednesday, warm air aloft will be gradually changing things over to sleet and freezing rain from south to north.
Wave One: Mix
While warm air will stream in unopposed aloft, the cold will put up a good fight at the surface. High pressure will be slowly sliding east across the Canadian Maritimes and I expect low level cold to hang on for a good long time. The map at left shows winds at the surface Wednesday evening. Notice NE winds still locking in cold air at the surface Wednesday night. The development of weak low pressure offshore will aid in this process. This wind will continue to cause problems even into the beginning of wave two which arrives Thursday morning just as this is beginning to erode. Several tenths of an inch of ice are possible and could lead to power outages especially if it doesn’t get a change to melt before the high winds associated with the cold front arrives.
Wave Two: Rain
Eventually, the cold air will be swept out of the way as SE winds pick up. A cold front will be approaching and ahead of it will be a line of heavy showers with some embedded thunder possible. A general inch to two inches of rain is likely which could lead to minor drainage/urban flooding. Despite that, no major issues are expected as we hardly have any snowpack to melt away.
Wave Two: Wind
As is usually the case with these storms, a band of strong winds will cross the area around the time of the heavy rain. The heavy rain will help mix some of those winds to the surface which could lead to scattered power outages. Notice the lack of bright pinks and purples in this map where we had them covering the entire region last week. Winds this week will be slightly weaker with 40-50 mph gusts most likely (last week we had 50-60 mph winds).
Wave Three: Light Mountain Rain/Snow
As cold air pours back into the area Thursday evening, an upper disturbance will pass overhead which will cause another batch of precip to move through. This will be most widespread in the mountains but everyone has a shot at a quick coating-2″ of snow as westerly winds bring the cold back in. This should move in late in the evening Thursday and should be out of here by dawn Friday.
More updates in the coming days.