DAYS 1-5 (MAY 21-25)

Cooler, drier air has arrived, but today it’s not with one of those bright blue sky days with fair weather clouds. Instead it will take place under a canopy of mid to high level cloud cover as a result of the frontal boundary staying just to our south while winds aloft are parallel to it (west to east) and a weak wave of low pressure moves by to our south this morning. This wave will bring some showers to eastern CT, RI, and southeastern MA, favoring the South Coast region, until about midday today before moving away. Still watching where the edge of the cloud canopy will be in regards to the potential for a nice sunset. Either way, enough thinning and clearing of the cloud deck takes place tonight for fairly optimal radiational cooling, leading to a pretty chilly (for late May) overnight and early morning on Friday. High pressure builds in with continued dry conditions and more sun Friday, though that will be more filtered with time through an increase in high cloudiness from the southwest as the day goes on. This cloud deck will start to thicken up Friday night into Saturday, but I remain fairly confident that the high pressure area, by then to our north and east, will have enough ability to keep our region dry much of Saturday’s daylight. Rain from an approaching low pressure wave should start to work in from southwest to northeast as early as the latter portion of the day but more likely holding off until sometime Saturday night, and this will lead to a fairly rainy and drizzly day on Sunday as the low makes its closest pass. I’m not expecting heavy rainfall, but enough to have to change outdoor plans that depend on dry weather. This middle day of the Memorial Day Weekend certainly looks the “worst”, as the holiday it self will start to show some improvement as low pressure departs to the east. How much clearing we see depends on how quickly any remaining low level moisture can be removed by a north to northwest air flow. But even with that, I still cannot rule out a passing shower. A little more refinement to this day’s forecast will come in the next few updates.

TODAY: Mostly cloudy. Morning showers possible South Coast. Highs 62-69. Wind NW 5-15 MPH.

TONIGHT: Clearing. Lows 38-45. Wind NW to N under 10 MPH.

FRIDAY: Increasing high clouds. Highs 61-68, coolest coast. Wind N to NE up to 10 MPH.

FRIDAY NIGHT: Thickening clouds. Lows 43-50. Wind calm.

SATURDAY: Cloudy. Rain potential increases south and west of Boston later in the day. Highs 58-65, coolest coast. Wind SE up to 10 MPH.

SATURDAY NIGHT / SUNDAY: Overcast. Periods of rain and drizzle. Areas of fog. Lows 45-52. Highs 52-59. Wind E to NE 5-15 MPH.

SUNDAY NIGHT: Cloudy. Lingering drizzle. Areas of fog. Chance of a shower. Lows 45-52. Wind NE to N up to 10 MPH.

MONDAY (MEMORIAL DAY): Mostly cloudy. A shower possible. Highs 58-65. Wind N to NW 5-15 MPH.

DAYS 6-10 (MAY 26-30)

An upper trough brings a shower chance each day May 26 & 27, but perhaps a better chance May 27 due to an accompanying surface disturbance / frontal system. Fair weather follows. Temperatures near to below normal.

DAYS 11-15 (MAY 31 – JUNE 4)

Watching for a couple relatively minor disturbances to bring passing shower chances in an otherwise mostly dry pattern with fairly seasonable though slightly variable temperatures.