Updated: 738 PM EDT Wed Apr 2 2025
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An approaching warm front will bring a period of light rain tonight into Thursday morning, with pockets of mixed wintry precipitation possible across northern MA tonight. Milder conditions arrive Thursday into Friday, with a stalled front possibly bringing a few showers near the south coast Thursday night into early Friday. Unsettled conditions continue this weekend, as a frontal system impacts the region, with cooler temperatures Saturday followed by milder conditions Sunday. Saturday appears to be the wetter of the two days. Drying out Monday, as the frontal system exits the region, along with cooler than normal temperatures overspreading the area much of next week.
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UNTIL 6 AM THURSDAY MORNING
740 PM update...
Forecast remains on track. WAA precip overspreading the region from the west. Airmass is initially dry, so leading edge of precip shield is partially evaporating before reaching the ground. This is also resulting in evaporative cooling thru the column, yielding some ice pellets mixing in with the rain at KALB. Although, with surface temp there at 43F, no impacts. Eventually, mid level warm nose climbs to +6C, too warm to support sleet. Thus, all rain overnight, with the only exception across the high elevations of western/central MA, where temps may lower to near freezing, supporting some spotty freezing rain at elevations above 1,000 ft. This remains a low prob, thus no changes to the forecast. Farther south across CT/RI and SE MA, less rainfall expected with best WAA farther northward.
Earlier discussion below.
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Key Messages:
* Periods of rain developing tonight
* Pockets of mixed wintry precip across the interior with spotty freezing rain possible over the higher elevations. Any travel impacts will be limited.
Higher clouds were already starting to arrive ahead of an approaching warm front, While the surface part of this front will probably not reach southern New England by daybreak Thursday, there will be plenty of warm air higher up. Most model soundings had peak warm nose temperatures of 4-6C. These soundings also showed a 4-6km deep layer of colder air beneath that warm nose. Overall, this should result in a period of sleet between about 8 PM to 1 AM before transitioning to all rain the rest of the night.
Rainfall amounts for most anticipated to be between 0.10-0.50 inches.
The other possibility is freezing rain. We had plenty of sunshine today, which should mean surface, not the standard air, temperatures well above freezing. The areas which would support this precipitation type should be isolated. With limited impact of icing this time of year, opted to not issue Winter Weather Advisories for either the freezing rain or sleet. The main areas of concern will be the higher terrain of the Worcester Hills and towards the Berkshires..
6 AM THURSDAY MORNING THROUGH FRIDAY
Key Messages:
* Milder Thu with rain becoming more spotty in the afternoon
The approaching warm front should finally move to our north during the day Thursday. This will lead to well above normal temperatures. Any precipitation should be in the form of rain. Once our region gets into the warm sector, then the rainfall chances become more spotty by late morning into the afternoon. A weak cold front should then try to pass through Thursday night.
One forecast concern is temperatures, and the corresponding impact on winds. Should more sunshine develop than currently forecast, we likely get deeper boundary layer mixing. With a 40-50 kt low level jet at 925 mb, that could lead to stronger winds than currently forecast, which is closer to the 90th percentile of the NationalBlend guidance but still below Wind Advisory thresholds.
Forecast high temperatures in the 60s away from the immediate coasts could reach the 70s in a few spots.
Drying out from north to south behind the aforementioned weak cold front..
FRIDAY NIGHT THROUGH WEDNESDAY
Updated 2:50 PM
Key Messages
* Pleasant early spring day Friday afternoon
* Cooler on Saturday followed by increasing shower chances Saturday afternoon & night, then warmer and not as wet Sunday
* Trending drier, but cooler next week
Friday...
Wavy frontal boundary impacts the region Fri/Sat and Sun, with a roller coaster ride in temps, along with wet and dry periods of weather. The frontal boundary is south of New England Fri, but close enough for moisture and associated showers to possibly clip the south coast Fri morning. Then in the afternoon, northern stream s/wv trough dives southeast from Quebec into Maine and then the Maritimes, shifting the frontal boundary and its moisture farther offshore and south of New England.
Thus, dry weather for the afternoon, along with increasing sunshine from north to south. Modest NW winds 10-15 mph will combine with a well mixed boundary layer to support highs in the low to mid 60s, about 10 degs warmer than normal for early April. Looks like a real nice afternoon, enjoy!
The Weekend...
The frontal boundary south of New England begins to return northward as a warm front Saturday. Thus, dry weather Sat morning will be replaced be increasing shower chances in the afternoon and night. Looks pretty wet/widespread showers Sat aftn/night, with ensemble probs of rainfall exceeding 0.10 inches at 100%. As for temps, much cooler Saturday with 1030+ mb high over the maritimes, providing cool air damming across SNE.
This is evident as 925 mb temps dip to 0C to +2C across the area Sat. Therefore, 60s on Friday will be replaced by temps in the 40s Sat, feeling even cooler along the coast, with east winds 10-15 mph off the chilly ocean (SST 36-42F).
Warm sector overspreads the region Sunday, however, not a clean warm sector airmass, with cold front quickly approaching from the west. Thus, not sure how much if any breaks of sunshine we will see Sunday, but warm sector airmass will provide dew pts in the 50s and highs 60-65. So definitely a warmer feel to the airmass than Sat. Bit of bust potential regarding temps Sun, +12C +16C at 925 mb Sunday afternoon. If more sunshine and mixing materializes, some locations away from the south coast could briefly pop into the 70s.
Ensembles hint at this, with low probs of 70+ highs. As for precip, not a washout Sunday and definitely not as wet as Sat, but can't rule out a few showers Sun along and ahead of frontal boundary. Given dew pts will be in the 50s, some SB instability combined with frontal scale forcing may support a low risk of thunder.
Monday/Tuesday/Wednesday...
Monday looks to be a transition day, with frontal boundary moving offshore and replaced by post frontal airmass. Thus, risk of early morning showers, especially over southeast MA, but trending drier in the afternoon. Seasonable temps, with highs in the 50s.
Tuesday and Wednesday, ensembles in good agreement on a fairly high amplitude long wave trough carving out over Quebec and New England.
This will support mainly dry weather (other than an isolated PM rain/snow shower with cold cyclonic flow aloft), but cooler than normal, with highs 45-50..
Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.
00z update...no change from previous TAFs.
Tonight...Moderate Confidence, mainly due to timing.
VFR trending to MVFR overnight. Local IFR across the higher terrain late. Mostly -SHRA, but risk for -PL across the interior with pockets of -FZRA higher elevations.
Thursday...Moderate Confidence.
Mainly IFR/MVFR with -SHRA in the morning becoming more spotty in the afternoon. Increasing SW winds with gusts to 25-35 kt developing.
Thursday Night...Moderate Confidence.
IFR/MVFR improving to VFR from NW to SE with passage of a cold front.
BOS TAF...High confidence in trends. Moderate confidence in timing. Risk for a spotty shower 03/01-05Z. Even lower risk for light PL during that time. Not enough confidence to include it in the TAF at this time, as it is more to not occur.
BDL TAF...High confidence in trends. Moderate confidence in timing.
Outlook /Friday Night through Monday/...
Friday Night: VFR.
Saturday: Mainly MVFR, with local IFR possible. SHRA.
Saturday Night: MVFR/IFR conditions possible. Breezy. SHRA.
Sunday: Mainly VFR, with local IFR possible. Breezy. Chance SHRA.
Sunday Night: Mainly MVFR, with local IFR possible. Breezy. SHRA likely.
Monday: MVFR/IFR conditions possible. Breezy. Chance SHRA.
Forecaster Confidence Levels:
Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent.
Winds and seas briefly diminish late this afternoon and early evening. Increasing SE winds then develop overnight, building seas once more. Considered gale force gusts during Thursday, but have more confidence in strong Small Craft Advisory conditions. Staggered the timing through tonight into Thursday. Winds should diminish closer to sunset, but rough seas likely to linger across the outer coastal waters.
Greater risk for reduced visibility in showers and fog across the waters east of MA than the southern waters. A warm front should move past the waters Thursday, with a cold front passing the waters late Thursday night.
Outlook /Friday Night through Monday/...
Friday Night: Winds less than 25 kt. Seas locally approaching 5 ft.
Saturday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers.
Saturday Night: Winds less than 25 kt. Seas up to 5 ft. Rain showers.
Sunday: Winds less than 25 kt. Areas of rough seas. Chance of rain showers.
Sunday Night: Winds less than 25 kt. Areas of rough seas. Rain showers likely.
Monday: Winds less than 25 kt. Areas of rough seas. Chance of rain showers.