DAYS 1-5 (MAY 22-26)
Heading into Memorial Day Weekend, we find ourselves in a somewhat familiar weather set-up here for this time of year. High pressure sits to our north, anchored in southeastern Canada with a drift eastward. A frontal boundary sits to our south and a wave of low pressure will be moving along it, approaching New England. The battle will be on between the dry air associated with the high pressure area and the moisture associated with the approaching / passing low. Today, the high is in control so we are dry with just filtered sunshine through a veil of high cloudiness (slightly thicker to the south but its edge often visible looking to the north). A light northeasterly air flow will keep the north-facing and east-facing coastal areas coolest today. Tonight, the clouds start to thicken, although they may remain thin enough for a little bit of sun to still be visible in northern and eastern portions of the WHW forecast area early Saturday. Otherwise, the slow turn of the battle in favor of the moisture means we’ll end up overcast. The dry air will be successful in holding off the low’s rain shield until at least Saturday evening in areas west and south of Boston, but eventually it gets in there and then spreads northeastward overnight into early Sunday. Some guidance keeps it dry into the first few hours of Sunday in eastern areas. I’m leaning toward the rain’s arrival by dawn throughout the region, however, making Sunday a pretty wet day. Rainfall amounts should be on the lighter side though, probably up to but mostly under a half inch before the steadiest rain tapers to occasional at night and then departs from west to east by dawn on Monday. Memorial Day itself should feature dominant cloud cover, although breaks of sun do become possible as the low pressure area moves away to the east and slightly drier air starts to work into the region in its wake. There can be a bit of drizzle or a leftover shower very early in the day, and we’ll have to watch for one more trough to swing through in the afternoon with the potential for a few more passing showers. Outdoor Memorial Day activities should take place under a mainly cloudy sky but without rain falling in most locations, although the ground likely to still be wet as most of these take place in the morning. Tuesday’s weather will be improved with dry conditions, though an upper trough over the region does promote a fair amount of cloud cover to limit sunshine that day as it looks this far in advance.
TODAY: Increasing high clouds. Highs 61-68, coolest coast. Wind N to NE up to 10 MPH.
TONIGHT: Thickening clouds. Lows 43-50. Wind calm.
SATURDAY: Cloudy. Highs 58-65, coolest coast. Wind SE up to 10 MPH.
SATURDAY NIGHT: Overcast. Rain arrives southwest to northeast. Lows 45-52. Wind E to NE 5-15 MPH.
SUNDAY: Overcast. Periods of rain and drizzle. Areas of fog. Highs 52-59. Wind E to NE 5-15 MPH.
SUNDAY NIGHT: Cloudy. Rain becomes intermittent. Areas of drizzle and fog. Lows 45-52. Wind NE to N up to 10 MPH.
MONDAY (MEMORIAL DAY): Mostly cloudy. Patchy drizzle and a brief shower possible early. An afternoon shower also possible. Highs 58-65. Wind N to NW 5-15 MPH.
MONDAY NIGHT: Partly cloudy. Lows 44-51. Wind NW up to 10 MPH.
TUESDAY: Cloud / sun intervals. Highs 61-68. Wind NW 5-15 MPH.
DAYS 6-10 (MAY 27-31)
Upper level low pressure and a couple passing surface disturbances bring shower and possible thunderstorm chances May 27 and 28, less of a chance May 29, along with cool conditions, before it departs to the east and is replaced by high pressure with fair and seasonable weather May 30-31 weekend.
DAYS 11-15 (JUNE 1-5)
Two disturbances bring passing shower chances during the first several days of June, with timing uncertain on them. For the most part it’s a dry and seasonable start to the first month of meteorological summer, based on current medium range indications.