882 FXUS61 KBOX 161706 AFDBOXArea Forecast Discussion National Weather Service Boston/Norton MA 106 PM EDT Tue Sep 16 2025
.SYNOPSIS... Dry weather with temperatures near or just warmer than average through mid week. A low chance for showers for coastal parts of southern New England Wednesday night into Thursday night as a low passes offshore. More autumn-like temperatures possible for this weekend following a cold front.
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.NEAR TERM /UNTIL 6 PM THIS EVENING/... Key Messages:
* Dry weather continues through today
Fog that develops overnight may linger a bit into the morning hours today. Other than that, dry weather expected through the day with highs in the mid 70s for most; temperatures may approach 80F for spots in the CT Valley.
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.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... Key Messages:
* Spot showers possible along the immediate south coast tonight
* The chance for some rain showers lingers through the day south of I-90, increasing heading into the evening hours Wednesday
A subtropical low passing south of the region may bring some spot showers along the immediate south coast late tonight into tomorrow morning. PWAT values begin to increase overnight from the south, but generally, the environment remains unfavorable for any widespread soaking rains through tomorrow. Lows are expected to be similar to Monday night`s, settling into the upper 40s and low 50s, with the coasts remaining slightly warmer in the upper 50s.
Mostly cloudy skies expected for Wednesday with isolated showers throughout the day. These will be primarily south of I-90 through the day, but a low chance remains for a stray shower or two moving further north. Highs expected to be in the low to mid 70s due to the expected cloud cover.
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.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Key Messages:
* Chance for showers increases Wednesday night with low passing offshore, though soaking rain not expected
* Drier and cooler weather moves in behind a dry cold front Friday, continuing through the weekend
The low passing south of the region will increase the chances for showers Wednesday night into Thursday morning. Ensemble guidance is leaning towards the highest chances for rain remaining south and east of I-84. The GEFS remains the driest of the ensembles, keeping probabilities for >0.1" of rainfall over 24 hours below even 10 percent for southern New England. The ECMWF ENS and GEPS continue to have up to 30-35 percent probabilities up to Boston for >0.1" over 24 hours by Thursday afternoon, increasing further south. Mean PWAT values peak late Wednesday night/early Thursday morning around 1.4" across southern New England. However, widespread soaking rains are not expected due to the lack of forcing and antecedent dry air aloft. Once this low passes, quiet conditions return by Thursday night.
A cold front is still expected to move through the region Friday afternoon and evening, leaving cooler and drier conditions in its wake. 925 mb temperatures fall as low as 5C Friday night after increasing to close to 20C ahead of the front during the afternoon Thursday and Friday. Saturday will feel more autumn-like with high pressure and a drier airmass building in behind the front and 925 mb temperatures around 10C during the day supporting highs mostly in the 60s. Lows may even dip into the upper 30s for some spots in the interior. With the incoming dry air, we could see an elevated fire risk Saturday. Temperatures begin to warm again going into the start of next week with continued high pressure.
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.AVIATION /18Z TUESDAY THROUGH SUNDAY/... Forecaster Confidence Levels...
Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.
Through 00Z...High confidence.
VFR. Light east/northeast winds.
Tonight...High Confidence.
Mainly VFR with IFR/MVFR at ORH/BED. Lower ceilings/vsbys at BOS are uncertain as the inland extent of lower ceilings and vsbys across eastern MA is uncertain. Included a TEMPO group from 08-12Z for IFR cigs and MVFR vsbys to encompass the most likely time of lower ceilings at BOS. Elsewhere VFR with light easterly winds.
Wednesday...High confidence.
Generally VFR with patches of MVFR in SHRA along the south coast, especially the Cape and Islands. Winds E up to 10 kts.
Wednesday Night...High Confidence
Mainly MVFR ceilings with -SHRA. Light easterly winds.
KBOS Terminal...Moderate confidence in TAF
Fog bank over Boston Harbor may result in a brief period of lower vsbys this afternoon. Also a chance for more fog/low ceilings early tomorrow, but confidence is moderate as most forecast guidances keeps this weather inland.
BDL Terminal...High confidence in TAF.
Outlook /Wednesday Night through Saturday/...
Wednesday Night: VFR. Chance SHRA, patchy FG.
Thursday: VFR. Slight chance SHRA, patchy FG.
Thursday Night through Friday: VFR. Widespread FG.
Friday Night: VFR. Breezy. Widespread FG.
Saturday: VFR. Breezy.
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.MARINE... Forecaster Confidence Levels...
Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent.
Through Wednesday...High confidence.
The latest guidance leaned more towards Small Craft Advisory criteria seas over the outer waters south of Block Island, so a Small Craft Advisory has been hoisted starting this morning continuing through 00z Thursday. Elsewhere, seas are expected to remain below 5 ft through this period.
Winds expected to remain light over the eastern waters and remain generally around 15 kts over the southern waters. Gusts to 20 kts are possible, but should remain infrequent.
Outlook /Wednesday Night through Saturday/...
Wednesday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers, patchy fog. Local visibility 1 nm or less.
Thursday: Winds less than 25 kt. Chance of rain showers, patchy fog. Local visibility 1 nm or less.
Thursday Night: Winds less than 25 kt. Slight chance of rain showers, patchy fog. Local visibility 1 nm or less.
Friday: Winds less than 25 kt. Widespread fog. Local visibility 1 nm or less.
Friday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Widespread fog.
Saturday: Winds less than 25 kt. Areas of seas approaching 5 ft.
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.BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 8 PM EDT Wednesday for ANZ256.
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SYNOPSIS...Belk/Hrencecin/FT NEAR TERM...Hrencecin SHORT TERM...Hrencecin LONG TERM...Hrencecin AVIATION...Hrencecin/RM MARINE...Hrencecin
NWS BOX Office Area Forecast Discussion