2:58AM
DAYS 1-5 (APRIL 11-15)
High pressure dominates today with fair mostly fair weather, but it’s not just that simple in the pattern, even on a “nice” day. Some of you, especially north of Boston, may encounter a dense fog to start the day and some may encounter a very frosty vehicle if heading out early in the day. There may also be a brief pop-up shower somewhere in eastern MA or nearby southern NH or northern RI along the boundary of a sea breeze which will form during the day and push slightly inland. A warm front approaches Thursday and the region briefly enters the warm sector from late Thursday night to sometime Saturday morning before the boundary is forced southward again by building high pressure in eastern Canada, a set-up typical for springtime in New England. By Sunday, low pressure will be approaching from the west, helping to add moisture to the mix as an onshore flow increases ahead of it and south of the high pressure area. Forecast details…
TODAY: Areas of fog mainly north and northwest of Boston early to mid morning. Partly sunny. Slight risk of an afternoon rain shower mainly eastern MA, southeastern NH, and northern RI. Highs 42-47 coast, 48-53 interior. Wind W up to 10 MPH interior but coastal sea breezes.
TONIGHT: Partly to mostly cloudy. A brief of very light rain or snow possible overnight. Lows 33-40. Wind variable up to 10 MPH.
THURSDAY: Partly sunny morning. Mostly cloudy afternoon. A period of light rain late day. Highs 43-50. Wind SE up to 10 MPH.
THURSDAY NIGHT: Mostly cloudy with a chance of light rain early, then partly cloudy with patchy fog. Temperatures steady 43-50 evening, rising to the lower 50s overnight. Wind SW up to 10 MPH.
FRIDAY: Partly cloudy. Highs 53-59 South Coast, 60-66 elsewhere except 67-75 interior valleys. Wind SW 5-15 MPH.
SATURDAY: Partly cloudy except becoming cloudy from northeast to southwest late-day with possible drizzle/fog at night. Lows from the upper 40s to lower 50s. Highs from the middle 50s to lower 60s morning, falling rapidly to 40s northeast to southwest by midday or afternoon, and more slowly to 30s at night.
SUNDAY: Overcast with areas of fog/drizzle and a chance of rain possibly mixed with sleet. Temperatures steady middle 30s to lower 40s.
DAYS 6-10 (APRIL 16-20)
April 16 (Patriots Day, Marathon Monday) is an important day in the region with a Red Sox game and the Boston Marathon taking place. Based on current timing, a ribbon of rain showers, possibly heavy, will have to cross the region from west to east, but the 2 big questions at this point will be timing of the heaviest rainfall and also whether or not any part of southern New England gets back into the warm air mass ahead of the main cold front from the west. Neither of these questions can be concretely answered 5 days in advance. Expecting drier air to arrive from the west by the middle of next week but a cold pool of air aloft arriving later in the period will bring the risk of some unsettled weather. Temperatures for the period will average generally below normal.
DAYS 11-15 (APRIL 21-25)
With the tendency for Canada to remain cold, warm air to be suppressed well to the south in the US, and a parade of disturbances transiting from the Pacific to the Atlantic via North America, it’s fair to say that an unsettled pattern and below normal temperatures will continue to be the rule into if not through this period.