Snow is Mother Nature’s natural refrigerant. And there is plenty of refrigerant around. It’s having an impact on temperatures, locally, and will continue to do so during the next few days. The result of this will be a warm up that is not as pronounced as it would be in a bare-ground situation. I hope that I have adjusted the forecast enough, based on this. The most immediate results of the snow pack will be temperatures that don’t go as high today as they would have, a warm front that is going to have a great struggle getting to or beyond the Merrimack and Nashoba Valleys tonight and early Friday, and only push northward just in time for a cold front coming from the west to pinch off any significant warmth, and that warm front resulting in snow/ice for parts of the region, instead of just plain rain, for a period of time tonight.
Today / Tonight… Small area of high pressure does bring sunshine today, that will start to fade during the afternoon as the warm front approaches. Watch for icy areas on the ground to persist through late morning, especially in shadowed areas where the sun doesn’t have the chance to heat the surface and melt the ice. By afternoon, it will have been above freezing long enough so that most icy areas should have melted. Tonight, clouds thicken up and overrunning precipitation arrives, especially from the Mass Pike region northward. The issue is that it will be cold enough again near the surface, especially over the interior, to promote icing if rain falls, and it will be cold enough aloft to support snow in areas near and north of Route 2, at least for a time, before it warms up aloft for sleet and freezing rain. So, some minor snow accumulation and icing issues may occur from east central and northeastern MA into southern NH tonight, especially in the 9PM-3AM window. To the south, spotty light rain and drizzle will develop tonight. Fog is possible in all locations, and may grow dense especially in northern MA and southern NH.
Friday / Friday night… Low pressure will track well north of the region, but its frontal systems will be playing with us. The cold air will be stubborn at the surface and the warm front will struggle to get by northern MA and into southern NH, and may never really make it there until sometime Friday afternoon. This will keep it cool, foggy, and drizzly, with even some freezing drizzle possible. To the south just patchy fog and drizzle as the milder air oozes into the region from the south across southeastern MA and RI. A cold front will sweep eastward across the region Friday afternoon and early evening, with a final push of mild air just ahead of it finally getting into the areas where it had trouble. But with this front comes an area of showers, some of which may be heavy. Thunderstorms cannot be completely ruled out as it will be unstable enough to trigger a few just ahead of the front. Later at night, the front will be offshore and clearing and drying will take place. Temperatures will not fall too much behind the front as this is not the leading edge of a very cold airmass, but it may cool enough to create some icy spots on the ground where rainwater and melted snow sit.
Saturday… Probably the nicest day, no storm system to deal with, no Arctic air (yet). A weak high pressure area will be our friend for the day.
Sunday… Transition day with some cloudiness and a risk of rain or snow showers as a trough and then an Arctic cold front pass through the region from west to east.
Next week… Our old buddy, the Polar Vortex, will take another southward journey into central and eastern Canada, turning our pattern cold to very cold for the last week of February. Though timing is still uncertain, we will not be without at least some threat of snow. So the higher confidence part of the extended forecast is the cold, and the lower confidence part will be the threat of any snow. Will be watching how things unfold…
Forecast for southeastern New England (southern NH, eastern MA, and RI)…
TODAY: Sunny morning. Increasing clouds afternoon. Highs 40-48. Wind W 5-15 MPH.
TONIGHT: Becoming cloudy. Developing areas of snow/sleet/freezing rain to the north, light rain/drizzle to the south. Some minor accumulation of ice with slippery areas especially east central and northeastern MA and a coating to 3 inches of snow and some sleet especially southern NH but also may work into north central and northeastern MA. Lows 30-38, mildest far to the south. Wind light variable to E.
FRIDAY: Overcast. Areas of fog and drizzle especially northern MA and southern NH. Showers and possibly a thunderstorms crossing the region west to east in the afternoon. Highs 43-51, being reached late-day and mildest to the south. Wind light E in northern MA and southern NH shifting to SE then S 5-15 MPH late. Wind SE to S 5-15 MPH increasing to 10-20 MPH to the south, with higher gusts in the afternoon.
SATURDAY: Partly cloudy. Low 32. High 46.
SUNDAY: Variably cloudy. Chance of rain and snow showers. Low 25. High 40.
MONDAY: Partly cloudy. Low 17. High 30.
TUESDAY: Partly cloudy. Low 10. High 25.
WEDNESDAY: Mostly cloudy. Chance of snow. Low 12. High 26.