2:31AM
DAYS 1-5 (MARCH 30-APRIL 3)
A very nice day often precedes the arrival of a storm, and that will be the case today as high pressure dominates with plenty of sunshine. The March Lion will bring southern New England a storm of rain/mix/snow to end the month and linger into the opening hours of April – not really atypical of this time of year, and only ironically on the 20th anniversary of the much larger and more impacting “April Fools Storm” of 1997. With this system just a day away from arrival, it is now time to try to pin down some details. What I do know is that low pressure will approach from the west and track eastward, passing just south of New England, spreading a large shield of precipitation across the region during Friday, peaking Friday night, and lingering into Saturday. The critical part of the forecast will be the position of a rain/snow line during the event, as well as whether or not enough warm air gets in aloft to result in sleet rather than snow for a portion of the storm. Also, a strip of freezing rain needs to be considered as temperatures may be warm enough aloft for rain and cold enough at the surface for it to freeze. I don’t think this will occur over a widespread area, however. This is how I think it plays out: Friday, precipitation moves eastward during the day in a couple batches, fighting dry air, but with periods of snow, which will have difficulty accumulating when it falls as is typical for spring daytime snow. Lighter mix/rain would likely occur in southern MA/CT/RI. Later in the day and into the evening a more solid area of precipitation is likely to move in from west to east, peaking during the overnight hours. During these hours is when the position and movement of the rain/mix/snow areas are most critical as this is when most of the snow accumulation would occur. It continues to be most likely that the most significant snow accumulation will occur away from the immediate coast and favor the higher elevations especially from central MA into southwestern NH, but this does not eliminate the possibility of significant accumulation elsewhere. For now I am going with a slightly colder scenario with a rain/snow line and a narrow band of sleet moving into eastern MA and Seacoast NH to about I-95 and in most areas south of the Mass Pike (I-90) with a tendency for this to happen more quickly in valley areas and more slowly in higher elevations. Where a changeover occurs except a narrow band of sleet and also some freezing rain favoring the southern higher elevations of central MA. During Saturday, the rain/mix/snow line will waver around as precipitation gradually tapers off from west to east, finally becoming mostly patchy light rain/drizzle with a little mix to the north. Current call on total snow accumulation: Under 1 inch South Coast and most of southeastern MA, 1-3 inches NH Seacoast to Cape Ann MA to Boston to Providence westward to Hartford, 3-6 inches from just west of I-95 to near I-495 in northeastern MA down the I-95 belt to I-90 then westward along I-90, 6-10 inches central MA into interior southern NH with higher amounts possible in highest elevations. Some adjustments may still be made to this forecast! A weak disturbance will bring some cloudiness and possibly a passing rain/snow shower Sunday. High pressure moves in Monday with nice weather, and combined with afternoon opening day baseball at Fenway Park will make the recently-departed storm seem like a distant memory. Forecast details…
TODAY: Sunshine, high clouds late. Highs 44-51. Wind N 5-15 MPH.
TONIGHT: Increasing clouds. Lows 27-34. Wind light N to NE.
FRIDAY: Overcast. Periods of snow except mix/rain southern MA/CT/RI. Highs 34-40. Wind NE 5-15 MPH.
FRIDAY NIGHT: Overcast. Snow except rain near South Coast then mix/change line advancing north and northwest into areas mentioned above. Lows 30-38. Wind NE to E 5-15 MPH, higher gusts in coastal areas.
SATURDAY: Overcast. Precipitation tapering off west to east with snow/mix interior NH to central MA, rain elsewhere. Highs 35-42. Wind NE to N 10-20 MPH, higher gusts possible.
SUNDAY: Variably cloudy. Chance of a few rain/snow showers. Lows 30-38. Highs 38-45.
MONDAY: Mostly sunny. Lows 28-35. Highs 44-51.
DAYS 6-10 (APRIL 4-8)
Active pattern. Rain/sleet possible April 4. Additional unsettled weather April 6-8. Temperatures below normal.
DAYS 11-15 (APRIL 9-13)
A break in the active pattern as it turns drier but temperatures remain mostly below to near normal.