Spring Snow Moves Through New England Today

Today, a northern stream system will likely cross near the Canadian border. This will drag a rather strong cold front across the region. This will bring colder temperatures and another round of precipitation. This northern stream system and a southern stream system south of New England will come close to phasing over New England, but, in the end, will remain separate. Snow (and rain/snow showers across southern areas) will likely come ahead and along the system's strong cold front Tuesday morning into the early afternoon.

Winter weather advisories have been posted for much of interior Maine and northernmost New Hampshire for the potential of several inches of snow. These alerts run until the pre-dawn hours Wednesday. Winds will pick up quickly behind the frontal passage, with wind advisories posted for the potential of gusts up to 50mph.

Heightened instability combined with the forcing from the front and energy from the shortwave may lead to widespread snow showers with embedded snow squalls along the cold front. Activity will likely be more widespread the farther north in New England you go. The cold front will cross much of New England during the morning hours. Some scattered snow showers may pop up behind the front in the afternoon as broad cyclonic flow continues.

As the northern stream system continues to move north and west, it will intensify and likely spawn a surface low over Maine. This would allow for more widespread snow across interior Maine and northern New Hampshire. A band of moderate snow will be possible, which is currently favored to set up over northern Maine. The steadiest and most widespread snow for Maine has trended toward a later arrival and departure. It will likely come by mid-afternoon and through the first part of the night.

Below: HRRR showing potential weather early this afternoon (1st image) and this evening (2nd image):

Most of northern New England will likely see a quick dusting to a few inches, with amounts increasing moving northward. A jackpot zone of 4-8 inches will be possible across interior Maine, especially moving into the central Highlands. This band of higher snowfall may end up rather narrow with sharp cutoffs in snowfall to the south and north of it (the crown of Maine will see lighter snowfall outside of the main forcing). This means some areas will likely end up under-achieving in our 5-8 inch zone.

Snowfall will gradually increase moving north and higher in elevation as snow showers become more persistent. Over Maine, the intensifying storm will likely set up a "deformation zone" where snowfall rates may become heavier for a time. This zone occurs when an air mass changes due to stretching and strengthening fronts. This will occur as the surface low strengthens over Maine. This will be the main driver for steadier, accumulating snowfall rates this afternoon and evening.

We do have some reservations about higher snowfall occurring. There are questions as to just how much snow can accumulate during the day Tuesday given the strong April sun angle. At this point in the year, it will take decently high snowfall rates to accumulate in the afternoon hours. With the storm ramping up in the early afternoon, it will be hard for accumulations to occur for a while until the sun begins to go down. With marginal temperatures, precipitation may come down as a mix or rain across interior Maine initially before heavier rates switch it to snow, as seen on some mesoscale models.

Below: HRRR showing potential weather around 3pm with some rainfall across lower elevations in Maine:

Total QPF for the system is also at a quarter inch or less, indicating a system that doesn't have a whole lot of moisture to work with. chances for at least 1 inch an hour snowfall rates top out at 50% for Maine's Central highlands, and that kind of intensity will be needed to get several inches of snow today.

Winds will kick up after the frontal passage as a low-level jet of 45-55mph crosses the region. With cold air advection and a northwest flow occurring in the afternoon, stronger wind gusts will have an easier time mixing to the ground. Gusts of 40-50mph are expected across much of southern and central New England this afternoon. The big question on gusts will be cloud cover. Should it remain stubbornly overcast, not as much mixing will occur and therefore gusts would be more isolated.

New England's next system will slowly approach at the end of the week. Clouds will likely begin to increase from west to east through the day Thursday. Precipitation chances will also increase from west to east later in the day, likely in the afternoon and evening for western areas. The system will likely sling showers at New England through Friday with the main batch of rain arriving on Saturday as the system moves south of New England.

It may be just cold enough for some mixing or snowfall at higher elevations at the onset of the system on Thursday as well as Friday night into Saturday morning. A switch to rain is likely for these areas as daytime heating occurs on Saturday. Overall, the extent of wintry precipitation looks minimal but could increase based on the overall setup and track, so trends will be watched.

Sunday remains very low confidence at this time, as it will all come down to the timing and evolution of the closed low near New England. As we just said, timing is up in the air, so while Sunday is currently looking much less wet than Saturday, the chance for showers remains. The system will be a typical spring time slow-mover, so it will be in the area all weekend. Sunday's rain chances could very well increase or decrease as the week goes on.