New England will be winter-like to start off the week, but that will quickly change. By midweek, temperatures will be back to spring-like levels. The main feature to watch this week will be a soaking storm set for Wednesday afternoon to Thursday morning.
MONDAY
Day two of New England's two-day cold snap will be very similar to Sunday, though with less wind. Mostly sunny skies and less wind will allow for afternoon temperatures to get a notch warmer than yesterday, though a vast majority of the region will remain below freezing. An expansive and cold area of high pressure remains planted to New England's west, which will remain in charge.
Below: Weather map for Monday:
Temperatures tonight will likely drop off quickly after sunset through about midnight. Great radiational cooling conditions will be in place with clear skies and light winds. Later in the night, an increasing southwest flow and warm air advection will slow the rate of cooling. Still, it will be another cold night before another modest-warm-up.
TUESDAY
The expansive area of high pressure will shift offshore on Tuesday. This will increase the southerly flow and allow for a notable warm-up in the afternoon. High temperatures will increase a good 25-35° region-wide from overnight lows by the late afternoon. Just about everyone will eventually make it above freezing with southern New England pushing well above freezing; some areas could push toward the 50° mark.
While much of the region will be dry throughout the day, a disturbance crossing to the north of New England will bring increasing clouds later in the day. This disturbance will lift its warm front through northern New England, providing the forcing for a period of rain and snow showers. These showers will generally be light and scattered with minimal accumulations. Showers will begin to increase around mid-afternoon and likely peak in coverage in the evening.
Below: HRRR showing potential weather Tuesday evening:
WEDNESDAY-THURSDAY
An intensifying system over the Great Lakes region will lift north and west of New England through this time. A deeper southerly flow will develop ahead of this system on Wednesday, allowing temperatures to continue to climb. This warm air advection will also allow showers to break out well ahead of the system on Wednesday. The storm's center will approach New England Wednesday night and pass to the north Thursday. This will bring the most widespread and heaviest rainfall later Wednesday into Thursday morning.
Showers could enter the picture as early as Wednesday morning for some areas, mainly across Vermont and western Massachusetts. Showers will continue through the day Wednesday, gradually increasing in coverage through the day. Showers will continue to fill in through Wednesday afternoon region-wide.
This initial batch of showers may be a wintry mix across portions of the northern tier of New England as cold air damming (CAD) will initially be in place. CAD is often stubborn and slower to scour out than what guidance shows ahead of time, so some freezing rain or even snow showers may be possible Wednesday afternoon across the north. All areas will eventually rise above freezing, allowing for plain rain by Wednesday evening region-wide. Light ice accumulations will be possible Wednesday across the north before melting.
Below: NAM showing potential weather early Wednesday afternoon (1st image) and overnight Wednesday (2nd image):
The bulk of the rainfall will come Wednesday night into Thursday morning for pretty much all of New England. Widespread and steady rain will wind down from west to east Thursday morning and into the early afternoon, though scattered showers may be present throughout the day Thursday. On Thursday, New England will be firmly within the system's warm sector, allowing for very mild conditions.
As the dry slot works into the region for the afternoon, a few breaks of sun will be possible. Should this manage to occur, temperatures could soar into the mid 50s to low 60s for southern and central New England. This would rely on breaks in the cloud cover, which is not a guarantee on Thursday. Scattered showers will also be hanging around through the day. Thursday could be similar to this past Saturday.
Below: Euro showing potential weather Thursday afternoon:
When all is said and done, it looks like a widespread half an inch to inch and a half of rain is expected across all of New England. Significant snowmelt remains possible as well, with an additional 1-2+ inches of runoff being added from snowmelt across northern New England. There remains a decently large range in just how much snowmelt will occur across northern New England, and this will determine the level of flooding threat for northern areas. The biggest potential issue would be ice breakup along rivers and ice jam flooding.
As of now, river ice across the north ranges from 6-12+ inches. Areas that have a thicker ice cover (12+ inches) will have a lower chance of ice movement and potential ice jam issues. At this point, widespread flooding is not expected, but localized issues where ice jams may occur is a possibility. The amount of overall runoff (rain and snow melt) will determine whether or not river ice will break up. Northern Maine will likely see much less snowmelt than other parts of the region as the snowpack has not yet ripened.
Across southern New England (also southern New Hampshire and southwest Maine), this will be a mainly beneficial rainfall as drought conditions in these areas continue to persist from the fall. Little to no snowpack remains to melt for southern New England and the flood threat is currently very low.
A robust low-level jet of 70-80mph will also cross the region Wednesday into Wednesday night, resulting in a period of gusty winds. At this point, a strong inversion looks to limit the wind threat, but gusts of up to 40-45mph will be in the cards. A rule of thumb is when a strong inversion is in place, to generally expect 50% of the winds from the low-levels to reach the surface. It will be difficult for stronger winds to mix to the surface.
FRIDAY
The storm's cold front will sweep across New England Thursday night, setting up a much cooler Friday. The air mass behind this front isn't as cold as the one at the beginning of this week. Temperatures will mainly drop back to near seasonable levels with cold overnights. As per usual with the day after storms, it may be gusty. The storm will likely continue to strengthen as it moves away, and could swing some snow showers into eastern Maine during the day. Other than that, it will be dry.
WEEKEND
A cold front and shortwave disturbance may dip through New England on Saturday, bringing a chance for snow and/or rain showers. At this point, any precipitation looks to be lighter and scattered in nature with nothing too organized. Temperatures will remain cooler.
Below: Current weather map for Saturday (March 8):
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