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Show Area Forecast Discussion - Taunton (Boston), MA (Boston/Cape Cod Area) Selection: |
| #1248193 (Received by flhurricane at: 7:30 PM 12.Oct.2025) AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 724 PM EDT Sun Oct 12 2025 .SYNOPSIS... A coastal storm brings rain and strong coastal winds into Monday night, along with the minor coastal flooding and erosion. Coastal low then begins to pull away for Tuesday, with decreasing rains and easing northerly winds. However an unseasonably cool airmass brings dry weather with below normal temperatures and a return of breezy northwest winds for mid to late next week. Temperatures then rebound back to above normal levels for the weekend. && .NEAR TERM /THROUGH MONDAY/... Key Messages: * Rain, heavy at times tonight into Monday with additional heavy rain Mon night across eastern MA * Gusty NE winds peak tonight into Monday morning. Strongest winds over Cape/Islands where gusts to 50+ mph expected with some power outages possible * Pockets of minor coastal flooding during high tide The brunt of the wind and rain impacts from this coastal storm will be felt tonight into Monday, although potential for heavy rain will linger into Mon night across eastern MA. Strong moisture inflow and convergence from easterly low level jet acting on PWATs 150-200% of normal will result in widespread rainfall which will fall heavy at times. Duration will be a factor to realizing heavy rainfall amounts as blocking ridge over Maritimes keeps coastal low will be quasi- stationary off the mid Atlc coast. Rainfall... Rain shield is slowly lifting north along the coast but steadier rain struggling to move into the interior as there is a dry layer in the low levels that will need to be overcome. The leading edge of the steady rain will gradually overspread the interior through the afternoon while heavier rain develops over the Cape/Islands. Heaviest rain will be tonight and Monday, with locally heavy rain lingering into Mon night across eastern MA. Deep moisture plume sets up across SNE tonight with increasing low level frontogenesis during Monday as the 850 mb front lifts north into SNE. Rain will gradually become more convective during Monday as elevated instability increases at the edge of a pseudo dry slot. Best chance of heavier convective showers and possible elevated thunder will be Monday afternoon and night, mainly eastern MA where heaviest rain is expected. HREF indicating 30 percent probs of 3 hr rainfall of 1"+ in eastern MA Mon afternoon, increasing to 50-70 percent across SE coastal MA and Cape/Islands Mon night. Rainfall will being to taper off in western New Eng Mon night, but convective showers will persist in eastern MA. Heaviest storm total rainfall through Tue will be across eastern MA/RI where widespread 2-3 inch amounts are expected, but locally 4-5 inches is possible in eastern MA. Hi-res guidance is targeting the eastern MA coast where locally heavy convective showers may contribute to higher amounts. Since the rainfall will be spread out over 48+ hours, significant flooding impacts are not expected, although some minor poor drainage street flooding is possible. Lesser rainfall amounts in western New Eng. Strong winds... No changes to the wind forecast. Strongest winds will be tonight into Mon morning across the Cape/Islands which will be within the axis of a gradually weakening 60-65 low level jet. Soundings show a shallow mixed layer supporting wind gusts to 50-60 mph over the Islands and up to 50 mph over Cape Cod. No changes to wind headlines. As the jet weakens as it lifts northward into SNE wind gusts will be less across rest of SNE with gusts to 35-45 mph along the immediate coast and 25-35 mph further inland. Given most trees remain fully leaved, some tree damage and power outages are possible, mainly over the Cape and Islands. Winds will diminish Mon afternoon through Mon night as the low level jet continues to weaken, but winds will remain gusty along the coast. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... Key Messages: * Rain with northeast to northerly breezes continue Tue, easing Tue night. Details: Still contending with lingering impacts from the coastal storm Tue, in the form of continued areas of rain and northerly breezes. The character of the rain trends more intermittent or even drizzle as drier air aloft works in on the northwest periphery of the coastal low`s circulation; steady light rains continuing for eastern/coastal MA and portions of eastern RI. NE to N winds gusting around 20-25 mph, but still up to 30 mph over the Cape and Islands during the day. Highs mid 50s to lower 60s are cooler than normal but will feel quite a bit cooler with the continued northerly breezes. Coastal low then finally pulls away Tue evening; rain then starts to taper off Tue night from W to E, although intermittent showers may still hold on overnight across the Cape and Islands. N to NW wind gusts will also be easing up Tue evening as well. Still possible we`ll have to watch for splashover around Nantucket for the Tue evening high tide, but easing NW winds lead to somewhat lower storm surge values at around a foot; with astro tide of 3.81 ft and would need a little higher storm surge to get to minor. Lows mid 40s to lower 50s. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Key Messages: * Below normal temps Wed thru Fri, with cloudy conditions and gusty north winds returning near the Cape and Islands. Minor coastal flooding possible for Nantucket. * Pattern change toward above normal temps by next weekend. Details: Wednesday through Friday: While the coastal low from the weekend/early in the week slowly meanders in the Canadian Maritimes early on Wed, a deep upper trough establishes itself over the Northeast. This feature per good agreement in ensembles, "catches" the coastal low and begins to pull it north or north-northwest toward Nova Scotia, which helps to tighten the NW pressure gradient again. This deep upper trough also ushers in an unseasonably cool airmass for mid to late in the week. Blustery and dry weather with below normal temperatures can be expected in this period for the interior and coastal plain. However some greater impacts for the Cape and Islands: below normal temps are expected here too, but will also be accompanied by cloudy weather, stronger north/northwest winds even some ocean-effect showers possible. Northerly winds could gust up to 30 mph over land, with gusts to gale force over the waters. These stronger northerly winds could also lead to renewed minor coastal flooding Wed-Thu for at least Nantucket and possibly some splashover for areas around Cape Cod Bay. High temps in the mid 50s though it may feel like the 40s with the breezes. Next Weekend: Significant pattern change indicated in ensembles in this forecast period as the deep upper trough moves offshore, and allows for strong 500 mb height rises and warmer temps to return. Full sun and dry weather are expected for the weekend. However 850 mb temps rise to above +10C by Sunday! Depending on how deep we can mix to, we may go from highs in the 50s Thurs to well into the 70s by the weekend. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Tonight through Monday: High confidence in trends but lower confidence on the timing. IFR-LIFR ceilings with IFR-MVFR visibilities in steady rain. Rain could lighten up some for the interior airports later Mon. E-NE winds 15-25 kt with gusts 25-30 kt inland, and around 35-50 kt near the coasts. Strongest gusts over the Cape and Islands. Strong LLWS up to 60 kt possible, especially towards the Cape and Nantucket tonight into Monday morning. KBOS Terminal...High confidence in TAF trends. Moderate confidence in timing. KBDL Terminal...High confidence in TAF trends. Moderate confidence in timing. Outlook /Wednesday through Friday/... Wednesday: VFR. Breezy. Wednesday Night: VFR. Windy with local gusts up to 30 kt. Thursday through Thursday Night: VFR. Windy with gusts up to 35 kt. Friday: VFR. Windy with local gusts up to 30 kt. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Storm and Gale warnings continue across the coastal waters into Monday. Expecting the strongest winds tonight, with gradual improvement Monday. Visibility reduced in rain and fog into Mon. Seas of 15-20 ft expected across the outermost coastal waters. Outlook /Wednesday through Friday/... Wednesday: Low risk for Small Craft Advisory winds with local gusts up to 30 kt. Areas of rough seas. Slight chance of rain showers. Wednesday Night: Strong winds with gusts up to 30 kt. Rough seas up to 9 ft. Chance of rain showers. Thursday: Strong winds with gusts up to 45 kt. Rough seas up to 10 ft. Chance of rain showers. Thursday Night: Moderate risk for gale force winds with gusts up to 40 kt. Rough seas up to 11 ft. Chance of rain showers. Friday: Low risk for gale force winds with gusts up to 35 kt. Areas of rough seas. Slight chance of rain showers. && .TIDES/COASTAL FLOODING... The biggest impact from this coastal storm will be beach erosion as significant wave action impacts the next 2 high tide cycles tonight into Monday. Storm surge along the RI south coast has been slower to ramp up and as a result little to no inundation occurred at high tide earlier this afternoon along the RI coast. The high tide along the east coast is later this afternoon and expect minor splashover here from the combination of a 1-1.5 ft surge and wave action. The greatest impacts will be over Nantucket and Edgartown on Martha`s Vineyard where a surge around 1.5 ft is expected. Current surge at Nantucket is 1.3 ft. The high tide tonight is lower, especially along the eastern MA coast where inundation is not expected. However, higher surge and waves will likely lead to minor inundation at Nantucket, Marthas Vineyard and ocean exposed RI south coast. The Monday afternoon high tide is also expected to be impacted with widespread minor inundation along the east coast and ocean exposed RI south coast. Storm surge of 1.5-2 ft will coincide with the highest seas during this time. Coastal Flood Advisories for future tides of concern will likely be issued with later forecasts as we move past each high tide where inundation is possible. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...Wind Advisory until 8 PM EDT Monday for MAZ022. High Wind Warning until 2 PM EDT Monday for MAZ023-024. Coastal Flood Advisory from 4 AM to 8 AM EDT Monday for MAZ023- 024. RI...High Wind Warning until 2 PM EDT Monday for RIZ008. Coastal Flood Advisory from midnight tonight to 4 AM EDT Monday for RIZ006>008. MARINE...Gale Warning until 8 PM EDT Monday for ANZ230-233-234. Gale Warning until 2 AM EDT Tuesday for ANZ231-250-251-254. Storm Warning until 8 AM EDT Monday for ANZ232-235-237-255-256. Gale Warning until 2 PM EDT Monday for ANZ236. && $$ |
| #1248174 (Received by flhurricane at: 2:48 PM 12.Oct.2025) AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 241 PM EDT Sun Oct 12 2025 .SYNOPSIS... A coastal storm brings rain and strong coastal winds into Monday night, along with the minor coastal flooding and erosion. Coastal low then begins to pull away for Tuesday, with decreasing rains and easing northerly winds. However an unseasonably cool airmass brings dry weather with below normal temperatures and a return of breezy northwest winds for mid to late next week. Temperatures then rebound back to above normal levels for the weekend. && .NEAR TERM /THROUGH MONDAY NIGHT/... Key Messages: * Rain, heavy at times tonight into Monday with additional heavy rain Mon night across eastern MA * Gusty NE winds peak tonight into Monday morning. Strongest winds over Cape/Islands where gusts to 50+ mph expected with some power outages possible * Pockets of minor coastal flooding during high tide The brunt of the wind and rain impacts from this coastal storm will be felt tonight into Monday, although potential for heavy rain will linger into Mon night across eastern MA. Strong moisture inflow and convergence from easterly low level jet acting on PWATs 150-200% of normal will result in widespread rainfall which will fall heavy at times. Duration will be a factor to realizing heavy rainfall amounts as blocking ridge over Maritimes keeps coastal low will be quasi- stationary off the mid Atlc coast. Rainfall... Rain shield is slowly lifting north along the coast but steadier rain struggling to move into the interior as there is a dry layer in the low levels that will need to be overcome. The leading edge of the steady rain will gradually overspread the interior through the afternoon while heavier rain develops over the Cape/Islands. Heaviest rain will be tonight and Monday, with locally heavy rain lingering into Mon night across eastern MA. Deep moisture plume sets up across SNE tonight with increasing low level frontogenesis during Monday as the 850 mb front lifts north into SNE. Rain will gradually become more convective during Monday as elevated instability increases at the edge of a pseudo dry slot. Best chance of heavier convective showers and possible elevated thunder will be Monday afternoon and night, mainly eastern MA where heaviest rain is expected. HREF indicating 30 percent probs of 3 hr rainfall of 1"+ in eastern MA Mon afternoon, increasing to 50-70 percent across SE coastal MA and Cape/Islands Mon night. Rainfall will being to taper off in western New Eng Mon night, but convective showers will persist in eastern MA. Heaviest storm total rainfall through Tue will be across eastern MA/RI where widespread 2-3 inch amounts are expected, but locally 4-5 inches is possible in eastern MA. Hi-res guidance is targeting the eastern MA coast where locally heavy convective showers may contribute to higher amounts. Since the rainfall will be spread out over 48+ hours, significant flooding impacts are not expected, although some minor poor drainage street flooding is possible. Lesser rainfall amounts in western New Eng. Strong winds... No changes to the wind forecast. Strongest winds will be tonight into Mon morning across the Cape/Islands which will be within the axis of a gradually weakening 60-65 low level jet. Soundings show a shallow mixed layer supporting wind gusts to 50-60 mph over the Islands and up to 50 mph over Cape Cod. No changes to wind headlines. As the jet weakens as it lifts northward into SNE wind gusts will be less across rest of SNE with gusts to 35-45 mph along the immediate coast and 25-35 mph further inland. Given most trees remain fully leaved, some tree damage and power outages are possible, mainly over the Cape and Islands. Winds will diminish Mon afternoon through Mon night as the low level jet continues to weaken, but winds will remain gusty along the coast. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... Key Messages: * Rain with northeast to northerly breezes continue Tue, easing Tue night. Details: Still contending with lingering impacts from the coastal storm Tue, in the form of continued areas of rain and northerly breezes. The character of the rain trends more intermittent or even drizzle as drier air aloft works in on the northwest periphery of the coastal low`s circulation; steady light rains continuing for eastern/coastal MA and portions of eastern RI. NE to N winds gusting around 20-25 mph, but still up to 30 mph over the Cape and Islands during the day. Highs mid 50s to lower 60s are cooler than normal but will feel quite a bit cooler with the continued northerly breezes. Coastal low then finally pulls away Tue evening; rain then starts to taper off Tue night from W to E, although intermittent showers may still hold on overnight across the Cape and Islands. N to NW wind gusts will also be easing up Tue evening as well. Still possible we`ll have to watch for splashover around Nantucket for the Tue evening high tide, but easing NW winds lead to somewhat lower storm surge values at around a foot; with astro tide of 3.81 ft and would need a little higher storm surge to get to minor. Lows mid 40s to lower 50s. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Key Messages: * Below normal temps Wed thru Fri, with cloudy conditions and gusty north winds returning near the Cape and Islands. Minor coastal flooding possible for Nantucket. * Pattern change toward above normal temps by next weekend. Details: Wednesday through Friday: While the coastal low from the weekend/early in the week slowly meanders in the Canadian Maritimes early on Wed, a deep upper trough establishes itself over the Northeast. This feature per good agreement in ensembles, "catches" the coastal low and begins to pull it north or north-northwest toward Nova Scotia, which helps to tighten the NW pressure gradient again. This deep upper trough also ushers in an unseasonably cool airmass for mid to late in the week. Blustery and dry weather with below normal temperatures can be expected in this period for the interior and coastal plain. However some greater impacts for the Cape and Islands: below normal temps are expected here too, but will also be accompanied by cloudy weather, stronger north/northwest winds even some ocean-effect showers possible. Northerly winds could gust up to 30 mph over land, with gusts to gale force over the waters. These stronger northerly winds could also lead to renewed minor coastal flooding Wed-Thu for at least Nantucket and possibly some splashover for areas around Cape Cod Bay. High temps in the mid 50s though it may feel like the 40s with the breezes. Next Weekend: Significant pattern change indicated in ensembles in this forecast period as the deep upper trough moves offshore, and allows for strong 500 mb height rises and warmer temps to return. Full sun and dry weather are expected for the weekend. However 850 mb temps rise to above +10C by Sunday! Depending on how deep we can mix to, we may go from highs in the 50s Thurs to well into the 70s by the weekend. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Today: High confidence in trends. Moderate confidence in timing. Continued deterioration toward MVFR-IFR through 20z from south to north as wind-driven rain moves in. Steady increase in E-NE wind speeds to around 15 kt with gusts is the 20s kt range interior airports. E-NE winds near the coastal airports pick up to around 20-25 kt with gusts to 35 kt by this afternoon, with gusts 35-40 kt Cape and Islands. Tonight through Monday: High confidence in trends but lower confidence on the timing. IFR-LIFR ceilings with IFR-MVFR visibilities in steady rain. Rain could lighten up some for the interior airports later Mon. E-NE winds 15-25 kt with gusts 25-30 kt inland, and around 35-50 kt near the coasts. Strongest gusts over the Cape and Islands. Strong LLWS up to 60 kt possible, especially towards the Cape and Nantucket tonight into Monday morning. KBOS Terminal...High confidence in TAF trends. Moderate confidence in timing. KBDL Terminal...High confidence in TAF trends. Moderate confidence in timing. Outlook /Wednesday through Friday/... Wednesday: VFR. Breezy. Wednesday Night: VFR. Windy with local gusts up to 30 kt. Thursday through Thursday Night: VFR. Windy with gusts up to 35 kt. Friday: VFR. Windy with local gusts up to 30 kt. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Storm and Gale warnings continue across the coastal waters into Monday. Expecting the strongest winds tonight, with gradual improvement Monday. Visibility reduced in rain and fog into Mon. Seas of 15-20 ft expected across the outermost coastal waters. Outlook /Wednesday through Friday/... Wednesday: Low risk for Small Craft Advisory winds with local gusts up to 30 kt. Areas of rough seas. Slight chance of rain showers. Wednesday Night: Strong winds with gusts up to 30 kt. Rough seas up to 9 ft. Chance of rain showers. Thursday: Strong winds with gusts up to 45 kt. Rough seas up to 10 ft. Chance of rain showers. Thursday Night: Moderate risk for gale force winds with gusts up to 40 kt. Rough seas up to 11 ft. Chance of rain showers. Friday: Low risk for gale force winds with gusts up to 35 kt. Areas of rough seas. Slight chance of rain showers. && .TIDES/COASTAL FLOODING... The biggest impact from this coastal storm will be beach erosion as significant wave action impacts the next 2 high tide cycles tonight into Monday. Storm surge along the RI south coast has been slower to ramp up and as a result little to no inundation occurred at high tide earlier this afternoon along the RI coast. The high tide along the east coast is later this afternoon and expect minor splashover here from the combination of a 1-1.5 ft surge and wave action. The greatest impacts will be over Nantucket and Edgartown on Martha`s Vineyard where a surge around 1.5 ft is expected. Current surge at Nantucket is 1.3 ft. The high tide tonight is lower, especially along the eastern MA coast where inundation is not expected. However, higher surge and waves will likely lead to minor inundation at Nantucket, Marthas Vineyard and ocean exposed RI south coast. The Monday afternoon high tide is also expected to be impacted with widespread minor inundation along the east coast and ocean exposed RI south coast. Storm surge of 1.5-2 ft will coincide with the highest seas during this time. Coastal Flood Advisories for future tides of concern will likely be issued with later forecasts as we move past each high tide where inundation is possible. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...Coastal Flood Advisory until 6 PM EDT this evening for MAZ007- 015-016-019-022>024. Wind Advisory until 8 PM EDT Monday for MAZ022. Coastal Flood Advisory from 4 AM to 8 AM EDT Monday for MAZ023- 024. High Wind Warning until 2 PM EDT Monday for MAZ023-024. RI...High Wind Warning until 2 PM EDT Monday for RIZ008. Coastal Flood Advisory from midnight tonight to 4 AM EDT Monday for RIZ006>008. MARINE...Gale Warning until 8 PM EDT Monday for ANZ230-233-234. Gale Warning until 2 AM EDT Tuesday for ANZ231-250-251-254. Storm Warning until 8 AM EDT Monday for ANZ232-235-237-255-256. Gale Warning until 2 PM EDT Monday for ANZ236. && $$ |
| #1248149 (Received by flhurricane at: 1:09 PM 12.Oct.2025) AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 103 PM EDT Sun Oct 12 2025 .SYNOPSIS... A coastal storm brings rain and strong coastal winds into Monday night, along with the minor coastal flooding and erosion. Unsettled weather lingers into Tuesday, especially across the eastern half of southern New England. Then blustery and generally dry with below normal temperatures for mid to late this workweek as an unseasonably cool air mass moves in. High pressure builds into the region next weekend with milder conditions and less wind. && .NEAR TERM /THROUGH TONIGHT/... Key Messages: * Rain arrives from south to north, especially this afternoon for most * Increasing E-NE winds, strongest across the Cape and islands * Pockets of minor coastal flooding during high tide Latest guidance suite did not provide much reason to alter the overall forecast. Did try to improve the onset timing of rainfall across out region. Really like the last few runs of the HRRR and the latest HREF for that aspect of this forecast. Thinking rainfall remains mainly south of the northern CT/RI and MA border this morning, although there is a chance for more scattered rainfall farther north by late morning. The widespread rainfall should really start to arrive through this afternoon. Gusty E-NE winds develop as the coastal low pressure to our south gets closer to the high pressure over the Maritimes. Expecting slightly below normal high temperatures. && .SHORT TERM /MONDAY/... Key Messages: * Steadiest and heaviest rain tonight into Monday * Strong E-NE winds developing into Mon along the coast, especially the Cape/Islands where gusts to 50+ mph expected with some power outages possible * Pockets of minor coastal flooding during high tide Rainfall... The brunt of the impacts from this coastal storm are expected tonight into Monday. This is the time period where we could see 1-3 inches of rainfall, especially across RI and eastern MA. The prolonged duration is important, because it is unlikely to result in significant flooding. The exception to that would be clogged storm drains possibly leading to poor-drainage flooding. There is not a tremendous amount of instability expected. However, there is relatively strong shear which may be enough to focus enough energy to result is a few thunderstorms. this would mainly be on Monday. Strong winds... E-NE winds will be ramping up this afternoon with the peak of the winds tonight into early Monday. Still looking like the 925 mb jet weakens late tonight into Monday. Contemplated expanding the Wind Advisory to Cape Ann and parts of the eastern MA coastline, but do not have enough confidence yet that the we will see 45+ mph wind gusts that far north. It is something that will need to be monitored. No changes to the current wind headlines at this time. Given most trees remain fully leaved, some tree damage and power outages are possible, mainly over the Cape and Islands. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Key Messages: * Coastal low slowly pulls away by Tue. Steadiest rains over eastern and coastal portions of RI and MA Mon night and Tue, with gradually decreasing north to northwest winds. * Minor coastal/tidal flooding possible at Nantucket for Tue aftn high tide, but water levels are slightly lower than what we will have with the afternoon high tides today and Mon. * Blustery and dry with below normal temperatures for mid to late week, as much as 10 degrees below normal. Generally dry, but could be some spotty showers over the Cape and Islands. Details: Monday Night and Tuesday: Still dealing with rain and northeast to northerly winds as we remain under the influence of the coastal low from the weekend. There is some solution spread with regard to how quickly the coastal low moves eastward/offshore from the mid-Atlantic states, with some deterministic models (00z ECMWF / 12z Canadian) showing a secondary low meandering around the NJ coast Mon night/Tue; we view this as an outlier outcome right now given limited support in ensemble membership analyses. Rain will continue to fall at a steady light to locally moderate clip early Mon night; as we move into the overnight Mon night to early Tue timeframe, the character of the rain trends more intermittent/showery or even drizzly for much of the interior as drier air starts working in aloft. Focus for steadier rains later Mon night through Tue is along the eastern MA coast aligned along an inverted trough, and it very slowly trends more intermittent in coastal eastern MA by Tue night. Additional rains covering the Mon night to Tue night period are around a half inch or less for much of Southern New England, but with an additional inch of rain still possible for coastal eastern MA. Winds will continue out of the NE Mon night with gusts 20-25 mph over the interior and around 30-35 mph in gusts for the Cape and the Islands. These will be coming around to the N and eventually NW with a decrease in speeds as we move into Tue, with gusts over the Cape and Islands around 25-30 mph for Tue. That probably will not translate to any additional wind-related impacts, but as winds come around to NW Tue, that could influence the coastal flood forecast for Nantucket, with Stevens Institute showing a continued 1 ft surge around the Tue aftn high tide which could support a worst-case minor coastal flood forecast for that high tide cycle. Wednesday thru Friday: The coastal low moves far enough away into the Canadian Maritimes but ends up slowing/stalling out as a deep upper trough sets up over New England. As this happens, it draws down an unseasonably cold airmass on NW winds. 925 mb temps drop to around zero Celsius or even a touch colder. This period is generally dry with strong sfc high pressure in control, except for possible ocean-enhanced cloud cover and limited chances at ocean-effect rain showers out over the Cape and Islands. However below normal temperatures are favored to go along with blustery NW winds which will make it feel cooler. Highs on Thurs may struggle to reach the low 50s! && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Today: High confidence in trends. Moderate confidence in timing. Continued deterioration toward MVFR-IFR through 20z from south to north as wind-driven rain moves in. Steady increase in E-NE wind speeds to around 15 kt with gusts is the 20s kt range interior airports. E-NE winds near the coastal airports pick up to around 20-25 kt with gusts to 35 kt by this afternoon, with gusts 35-40 kt Cape and Islands. Tonight through Monday: High confidence in trends but lower confidence on the timing. IFR-LIFR ceilings with IFR-MVFR visibilities in steady rain. Rain could lighten up some for the interior airports later Mon. E-NE winds 15-25 kt with gusts 25-30 kt inland, and around 35-50 kt near the coasts. Strongest gusts over the Cape and Islands. Strong LLWS up to 60 kt possible, especially towards the Cape and Nantucket tonight into Monday morning. KBOS Terminal...High confidence in TAF trends. Moderate confidence in timing. KBDL Terminal...High confidence in TAF trends. Moderate confidence in timing. Outlook /Monday Night through Thursday/... Monday Night: Mainly IFR, with local MVFR possible. Strong winds with local gusts up to 40 kt. RA, isolated TSRA, patchy BR. Tuesday: MVFR/IFR conditions possible. Windy with areas of gusts up to 30 kt. Chance RA. Tuesday Night: Mainly VFR, with local MVFR possible. Breezy. Chance RA. Wednesday: VFR. Windy with local gusts up to 30 kt. Slight chance SHRA. Wednesday Night: VFR. Windy with local gusts up to 30 kt. Chance SHRA. Thursday: VFR. Strong winds with local gusts up to 40 kt. Slight chance SHRA. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Storm and Gale warnings continue across the coastal waters into Monday. Expecting the strongest winds tonight, with some improvement Monday. Visibility reduced in rain and fog into Mon. Seas of 15-20 ft expected across the outermost coastal waters, with 4-8 ft closer to shore outside of the bays and harbors. Outlook /Monday Night through Thursday/... Monday Night: Strong winds with gusts up to 40 kt. Rough seas up to 16 ft. Rain, chance of thunderstorms, patchy fog. Visibility 1 nm or less. Tuesday: Strong winds with gusts up to 35 kt. Rough seas up to 13 ft. Rain likely. Local visibility 1 to 3 nm. Tuesday Night: Low risk for Small Craft Advisory winds with local gusts up to 30 kt. Rough seas up to 11 ft. Chance of rain. Wednesday: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Chance of rain showers. Wednesday Night: Strong winds with gusts up to 35 kt. Rough seas up to 8 ft. Chance of rain showers. Thursday: Strong winds with local gusts up to 45 kt. Rough seas up to 8 ft. Chance of rain showers. && .TIDES/COASTAL FLOODING... The biggest impact from this coastal storm will be beach erosion as significant wave action impacts 3 successive tide cycles today into Monday. Regarding inundation potential, a Coastal Flood Advisory continues for this afternoon`s high tide for the east coast MA and RI south coast. We think the greatest impacts with this high tide will be along the ocean-exposed RI coast from Narragansett to Westerly, where highest surge up to 2 ft expected with minor inundation. Other areas of minor inundation include Nantucket and Edgartown on Martha`s Vineyard. Along the rest of the eastern MA coast, storm surge anticipated to be 1-1.5 ft with increasing wave action leading to pockets of minor splashover. The late high tide tonight is lower, especially along the eastern MA coast where inundation is not expected. However, higher surge and waves will likely lead to minor inundation at Nantucket, Marthas Vineyard and ocean exposed RI south coast. The Monday afternoon high tide is also expected to be impacted with widespread minor inundation along the east coast and ocean exposed RI south coast. Storm surge of 1.5-2 ft will coincide with the highest seas during this time. Coastal Flood Advisories for future tides of concern will likely be issued with later forecasts as we move past each high tide where inundation is possible. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...Coastal Flood Advisory until 6 PM EDT this evening for MAZ007- 015-016-019-022>024. Wind Advisory from 5 PM this afternoon to 8 PM EDT Monday for MAZ022. High Wind Warning from 5 PM this afternoon to 2 PM EDT Monday for MAZ023-024. RI...High Wind Warning from 5 PM this afternoon to 2 PM EDT Monday for RIZ008. Coastal Flood Advisory until 3 PM EDT this afternoon for RIZ006>008. MARINE...Gale Warning until 8 PM EDT Monday for ANZ230. Gale Warning until 8 PM EDT Monday for ANZ231-233-234-250-251- 254. Storm Warning until 8 AM EDT Monday for ANZ232-235-237-255-256. Gale Warning until 2 PM EDT Monday for ANZ236. && $$ |
| #1248108 (Received by flhurricane at: 3:12 AM 12.Oct.2025) AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 306 AM EDT Sun Oct 12 2025 .SYNOPSIS... A coastal storm brings rain and strong coastal winds into Monday night, along with the minor coastal flooding and erosion. Unsettled weather lingers into Tuesday, especially across the eastern half of southern New England. Then blustery and generally dry with below normal temperatures for mid to late this workweek as an unseasonably cool air mass moves in. High pressure builds into the region next weekend with milder conditions and less wind. && .NEAR TERM /THROUGH TODAY/... Key Messages: * Rain arrives from south to north, especially this afternoon for most * Increasing E-NE winds, strongest across the Cape and islands * Pockets of minor coastal flooding during high tide Latest guidance suite did not provide much reason to alter the overall forecast. Did try to improve the onset timing of rainfall across out region. Really like the last few runs of the HRRR and the latest HREF for that aspect of this forecast. Thinking rainfall remains mainly south of the northern CT/RI and MA border this morning, although there is a chance for more scattered rainfall farther north by late morning. The widespread rainfall should really start to arrive through this afternoon. Gusty E-NE winds develop as the coastal low pressure to our south gets closer to the high pressure over the Maritimes. Expecting slightly below normal high temperatures. && .SHORT TERM /TONIGHT THROUGH 6 PM MONDAY/... Key Messages: * Steadiest and heaviest rain tonight into Monday * Strong E-NE winds developing into Mon along the coast, especially the Cape/Islands where gusts to 50+ mph expected with some power outages possible * Pockets of minor coastal flooding during high tide Rainfall... The brunt of the impacts from this coastal storm are expected tonight into Monday. This is the time period where we could see 1-3 inches of rainfall, especially across RI and eastern MA. The prolonged duration is important, because it is unlikely to result in significant flooding. The exception to that would be clogged storm drains possibly leading to poor-drainage flooding. There is not a tremendous amount of instability expected. However, there is relatively strong shear which may be enough to focus enough energy to result is a few thunderstorms. this would mainly be on Monday. Strong winds... E-NE winds will be ramping up this afternoon with the peak of the winds tonight into early Monday. Still looking like the 925 mb jet weakens late tonight into Monday. Contemplated expanding the Wind Advisory to Cape Ann and parts of the eastern MA coastline, but do not have enough confidence yet that the we will see 45+ mph wind gusts that far north. It is something that will need to be monitored. No changes to the current wind headlines at this time. Given most trees remain fully leaved, some tree damage and power outages are possible, mainly over the Cape and Islands. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Key Messages: * Coastal low slowly pulls away by Tue. Steadiest rains over eastern and coastal portions of RI and MA Mon night and Tue, with gradually decreasing north to northwest winds. * Minor coastal/tidal flooding possible at Nantucket for Tue aftn high tide, but water levels are slightly lower than what we will have with the afternoon high tides today and Mon. * Blustery and dry with below normal temperatures for mid to late week, as much as 10 degrees below normal. Generally dry, but could be some spotty showers over the Cape and Islands. Details: Monday Night and Tuesday: Still dealing with rain and northeast to northerly winds as we remain under the influence of the coastal low from the weekend. There is some solution spread with regard to how quickly the coastal low moves eastward/offshore from the mid-Atlantic states, with some deterministic models (00z ECMWF / 12z Canadian) showing a secondary low meandering around the NJ coast Mon night/Tue; we view this as an outlier outcome right now given limited support in ensemble membership analyses. Rain will continue to fall at a steady light to locally moderate clip early Mon night; as we move into the overnight Mon night to early Tue timeframe, the character of the rain trends more intermittent/showery or even drizzly for much of the interior as drier air starts working in aloft. Focus for steadier rains later Mon night through Tue is along the eastern MA coast aligned along an inverted trough, and it very slowly trends more intermittent in coastal eastern MA by Tue night. Additional rains covering the Mon night to Tue night period are around a half inch or less for much of Southern New England, but with an additional inch of rain still possible for coastal eastern MA. Winds will continue out of the NE Mon night with gusts 20-25 mph over the interior and around 30-35 mph in gusts for the Cape and the Islands. These will be coming around to the N and eventually NW with a decrease in speeds as we move into Tue, with gusts over the Cape and Islands around 25-30 mph for Tue. That probably will not translate to any additional wind-related impacts, but as winds come around to NW Tue, that could influence the coastal flood forecast for Nantucket, with Stevens Institute showing a continued 1 ft surge around the Tue aftn high tide which could support a worst-case minor coastal flood forecast for that high tide cycle. Wednesday thru Friday: The coastal low moves far enough away into the Canadian Maritimes but ends up slowing/stalling out as a deep upper trough sets up over New England. As this happens, it draws down an unseasonably cold airmass on NW winds. 925 mb temps drop to around zero Celsius or even a touch colder. This period is generally dry with strong sfc high pressure in control, except for possible ocean-enhanced cloud cover and limited chances at ocean-effect rain showers out over the Cape and Islands. However below normal temperatures are favored to go along with blustery NW winds which will make it feel cooler. Highs on Thurs may struggle to reach the low 50s! && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Today: High confidence in trends. Moderate confidence in timing. Ceilings trend to VFR/MVFR levels all terminals between 12-16z from south to north. Continued deterioration toward MVFR-IFR 15-20z timeframe from south to north as wind-driven rain moves in. Steady increase in E-NE wind speeds to around 15 kt with gusts is the 20s kt range interior airports. E-NE winds near the coastal airports pick up to around 20-25 kt with gusts to 35 kt by this afternoon, with gusts 35-40 kt Cape and Islands. Tonight through Monday: High confidence in trends but lower confidence on the timing. IFR-LIFR ceilings with IFR-MVFR visibilities in steady rain. Rain could lighten up some for the interior airports later Mon. E-NE winds 15-25 kt with gusts 25-30 kt inland, and around 35-50 kt near the coasts. Strongest gusts over the Cape and Islands. Strong LLWS up to 60 kt possible, especially towards the Cape and Nantucket tonight into Monday morning. KBOS Terminal...High confidence in TAF trends. Moderate confidence in timing. KBDL Terminal...High confidence in TAF trends. Moderate confidence in timing. Outlook /Monday Night through Thursday/... Monday Night: Mainly IFR, with local MVFR possible. Strong winds with local gusts up to 40 kt. RA, isolated TSRA, patchy BR. Tuesday: MVFR/IFR conditions possible. Windy with areas of gusts up to 30 kt. Chance RA. Tuesday Night: Mainly VFR, with local MVFR possible. Breezy. Chance RA. Wednesday: VFR. Windy with local gusts up to 30 kt. Slight chance SHRA. Wednesday Night: VFR. Windy with local gusts up to 30 kt. Chance SHRA. Thursday: VFR. Strong winds with local gusts up to 40 kt. Slight chance SHRA. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Storm and Gale warnings continue across the coastal waters into Monday. Expecting the strongest winds tonight, with some improvement Monday. Visibility reduced in rain and fog into Mon. Seas of 15-20 ft expected across the outermost coastal waters, with 4-8 ft closer to shore outside of the bays and harbors. Outlook /Monday Night through Thursday/... Monday Night: Strong winds with gusts up to 40 kt. Rough seas up to 16 ft. Rain, chance of thunderstorms, patchy fog. Visibility 1 nm or less. Tuesday: Strong winds with gusts up to 35 kt. Rough seas up to 13 ft. Rain likely. Local visibility 1 to 3 nm. Tuesday Night: Low risk for Small Craft Advisory winds with local gusts up to 30 kt. Rough seas up to 11 ft. Chance of rain. Wednesday: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Chance of rain showers. Wednesday Night: Strong winds with gusts up to 35 kt. Rough seas up to 8 ft. Chance of rain showers. Thursday: Strong winds with local gusts up to 45 kt. Rough seas up to 8 ft. Chance of rain showers. && .TIDES/COASTAL FLOODING... The biggest impact from this coastal storm will be beach erosion as significant wave action impacts 3 successive tide cycles today into Monday. Regarding inundation potential, a Coastal Flood Advisory continues for this afternoon`s high tide for the east coast MA and RI south coast. We think the greatest impacts with this high tide will be along the ocean-exposed RI coast from Narragansett to Westerly, where highest surge up to 2 ft expected with minor inundation. Other areas of minor inundation include Nantucket and Edgartown on Martha`s Vineyard. Along the rest of the eastern MA coast, storm surge anticipated to be 1-1.5 ft with increasing wave action leading to pockets of minor splashover. The late high tide tonight is lower, especially along the eastern MA coast where inundation is not expected. However, higher surge and waves will likely lead to minor inundation at Nantucket, Marthas Vineyard and ocean exposed RI south coast. The Monday afternoon high tide is also expected to be impacted with widespread minor inundation along the east coast and ocean exposed RI south coast. Storm surge of 1.5-2 ft will coincide with the highest seas during this time. Coastal Flood Advisories for future tides of concern will likely be issued with later forecasts as we move past each high tide where inundation is possible. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...Coastal Flood Advisory from 2 PM this afternoon to 6 PM EDT this evening for MAZ007-015-016-019-022>024. Wind Advisory from 5 PM this afternoon to 8 PM EDT Monday for MAZ022. High Wind Warning from 5 PM this afternoon to 2 PM EDT Monday for MAZ023-024. RI...High Wind Warning from 5 PM this afternoon to 2 PM EDT Monday for RIZ008. Coastal Flood Advisory from 11 AM this morning to 3 PM EDT this afternoon for RIZ006>008. MARINE...Gale Warning from 2 PM this afternoon to 8 PM EDT Monday for ANZ230. Gale Warning from 11 AM this morning to 8 PM EDT Monday for ANZ231-233-234-250-251-254. Storm Warning from 2 PM this afternoon to 8 AM EDT Monday for ANZ232-235-237-255-256. Gale Warning from 2 PM this afternoon to 2 PM EDT Monday for ANZ236. && $$ |
