


Area Forecast Discussion
Issued by NWS Boston, MA
Issued by NWS Boston, MA
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011 FXUS61 KBOX 181750 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 150 PM EDT Sat Oct 18 2025 .SYNOPSIS... High pressure takes a hold of the weather pattern this weekend bringing less wind and warmer afternoon temperatures. A Strong Frontal system begins to approach the region on Sunday, bringing gusty southerly winds with above-normal temperatures. The frontal system arrives Monday morning, bringing rain and a chance for thunderstorms. The pattern remains unsettled as we head into the middle of next week. && .NEAR TERM /THROUGH TONIGHT/... Upper-level ridge axis moves directly overhead tomorrow, while high pressure just off shore of the Carolinas begins to retreat further south. What this means for us is another pleasant day with highs again reaching the low to mid 60s. Skies will start the day off mostly sunny, but high clouds begin to filter in by early afternoon as mid to upper level moisture arrives with the ridge axis. It will be noticeably less windy today, with light and variable to calm winds across the region. && .SHORT TERM /SUNDAY/... Tonight: Winds aloft begin to flip SW overnight, advecting in warmer air aloft with 850mb temps increasing to +11C. Despite calm winds at the surface, high clouds and warming temps aloft will keep overnight lows a bit warmer tonight, in the mid to upper 40s. Dewpoints gradually rise overnight, which could lead to patchy radiation fog in low-lying areas. Tomorrow: Mid-level winds continue to increase tomorrow ahead of a robust shortwave over the Ohio River Valley. Once diurnal heating kicks in on Sunday, the winds aloft will begin to mix down, bringing southerly gusts of 15-20mph. The southerly winds and WAA will help warm temps into the upper 60s to low 70s. High clouds continue to stream in ahead of the shortwave with mainly filtered sunshine throughout the day. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... Key Messages: * Looking unsettled next week as multiple shortwaves move through the region. Timing questions remain with the passage of a cold front and secondary low pressure some time Sunday night into Monday. The 17/12Z NAM was on the more progressive end of the guidance. Given the synoptic pattern of a high pressure to the east and a secondary low pressure along this front, favored a slower timing that was more in line with the 17/12Z GFS and CMC solutions. This keeps most of Sunday dry, with showers arriving from west to east after sunset. Expecting showers across most of our region by the time of the Monday morning commute. Beyond this time, the timing of showers remains uncertain. Most of the 17/12Z guidance suite develops more of a mid level cutoff, but cannot agree on where this cutoff will be. This cutoff then appears like it will get kicked out over the Atlantic by a more potent mid level trough midweek. This pattern typically leads to a prolonged period of unsettled weather. Looking like a trend toward below normal temperatures next week with periods of showers. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 18Z TAF Update: This Afternoon...High Confidence. VFR. Light and variable winds this afternoon with localized sea breezes for coastal terminals. FEW-SCT mid-level clouds mid afternoon to early evening. Tonight...High Confidence. Light S/SSW winds overnight. Chance for localized ground or valley fog. Not high enough in coverage to include in TAFs, except a TEMPO mention of BR for the valley terminals and FMH. Sunday... High Confidence VFR. Increasing southerly winds gusting up to 15-20 knots. Sunday Night...High Confidence. Increasing mid-level clouds. IFR-MVFR ceiling spread from west to east 03z-10z. KBOS Terminal...High Confidence in TAF. ESE winds 6-8 kts this afternoon. Winds kick back S after 00z. KBDL Terminal...High Confidence in TAF. VFR. Light winds under 5 knots. Outlook /Sunday Night through Thursday/... Sunday Night: Mainly VFR, with local IFR possible. Breezy. Chance SHRA. Monday: Mainly MVFR, with local IFR possible. Windy with gusts up to 35 kt. Chance SHRA, slight chance TSRA. Monday Night: VFR. Windy with local gusts up to 30 kt. Chance SHRA. Tuesday: VFR. Breezy. Tuesday Night: VFR. Chance SHRA. Wednesday: Mainly VFR, with local MVFR possible. Breezy. Chance SHRA. Wednesday Night through Thursday: VFR. Breezy. Slight chance SHRA. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Through Sunday...High confidence. High pressure brings calm winds and decreasing seas today and tonight, ranging from 3-6 feet. Winds gradually flip south on Sunday and begin increasing to 15-20knots on Sunday. Seas remain around 3-6 feet Outlook /Sunday Night through Thursday/... Sunday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Chance of rain showers. Monday: Low risk for gale force winds with gusts up to 40 kt. Areas of rough seas. Rain showers likely, slight chance of thunderstorms. Monday Night: Winds less than 25 kt. Areas of rough seas. Chance of rain showers, slight chance of thunderstorms. Tuesday: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain showers. Tuesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers. Wednesday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers, slight chance of thunderstorms. Wednesday Night: Winds less than 25 kt. Local rough seas. Chance of rain showers. Thursday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 8 AM EDT Sunday for ANZ250-254-255. && $$ SYNOPSIS...Belk/KP NEAR TERM...KP SHORT TERM...KP LONG TERM...Belk/KP AVIATION...McMinn/Mensch MARINE...KP