Troughing will be the name of the game for New England through much of this upcoming week. This will bring some unsettled weather, though there will be many more dry times than wet times after Monday night.
MONDAY & TUESDAY
A storm system will move through the Great Lakes region on Memorial day and eventually to the north of New England. This will send the system’s cold front across New England. As typical in this setup, very moist air will surge into New England from the south ahead of the front, priming the atmosphere for bouts of heavy rain.
With that said, the timing of the heaviest rain will be for the evening and into the first part of the night. Scattered, light showers will likely break out ahead of the front by Monday morning and slowly fill in as the day goes on from west to east. Much of the day will not be washed out for services, though the day certainly won’t be fully dry. In the evening, bouts of torrential downpours will be possible as the front moves through and taps into the moisture.
HRRR showing expected weather Monday afternoon (1st image) and Monday evening (2nd image):
Most of New England will end up with a half an inch to inch and a half of rain. The nature of the downpours could lead to some localized, minor street and poor drainage flooding. Downpours will be progressive, meaning they will be moving along at a good clip. Storm training is also not expected. Both of these points will really limit any flooding.
This setup is also ripe for upslope enhancement of rainfall, meaning higher terrain areas (White Mountains, Maine Mountains, Berkshires, southern Greens) will very likely end up seeing the most rainfall.
With the progressive nature of the system, the rain looks to quickly clear out well before sunrise for most of New England (the exception being eastern Maine). The day will likely start off cloudy with some clearing from west to east. The actual cold front of the system will likely cross the region during the day, which could trigger some light, scattered showers, but this remains a low chance.
HRRR showing expected weather around sunrise Tuesday:
The thick clouds and showers will keep highs down on Monday, but once partial sunshine breaks out for Tuesday afternoon, highs will climb to the 70s and 80s once again.
WEDNESDAY & THURSDAY
New England will remain in a trough during this time with broad cyclonic flow continuing. A secondary cold front will likely drop into northern New England Wednesday morning. This will occur as the first cold front from earlier in the week remains stalled offshore. An area of low pressure will likely ride up this front toward New England Wednesday night into Thursday morning.
This will result in continued scattered shower chances through Thursday morning. A vast majority of this period will be dry, and skies are unlikely to remain completely overcast with times of clouds and sun both days between the showers. With broad cyclonic flow and troughing continuing, temperatures will be on the downward trend, but it doesn't look like it will be that cool compared to averages, with upper 60s to mid 70s with Wednesday being the warmest day.
GFS and Euro showing potential weather Wednesday afternoon (1st image) and Thursday morning (2nd image):
FRIDAY
Friday is currently looking to be a bit of a transition day for New England. The trough of low pressure to New England's east will begin sliding away with a ridge of high pressure building in from the west. This will help build more stable dry air into New England.
The question for Friday will be timing. If the trough of low pressure remains close enough, it could continue to cycle some scattered showers into New England. Eastern Maine has the highest chance of showers on Friday as they will )naturally) be the closest to the exiting trough. Highs are looking to remain seasonable for late May.
Weather map for Friday morning showing the departing low to the northeast and the building high to our west:
WEEKEND
As of now, the timing of the ridge of high pressure looks to line up nicely with the weekend. If this timing holds up, it would bring dry weather and warming temperatures for Saturday and Sunday.
Weather map for Saturday morning:
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