AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 108 PM EST Fri Dec 19 2025 .WHAT HAS CHANGED... Strong to damaging wind gusts have been experienced across parts of southern New England, these winds are expected to continue into the early afternoon. A shift in wind direction from south to west occurs there after with wind gusts this evening and overnight between 35 and 50 MPH, prompting the extension of the Wind Advisory into early Saturday morning. && .KEY MESSAGES... - Damaging southerly gusts through this afternoon as a powerful low-level jet and cold front push across the region. Drying conditions late today with strong post frontal westerly winds. - Quiet conditions Saturday and Monday, with Sunday featuring the potential for additional strong wind gusts. - Shortwave brings a period of gusty winds and much colder air Sunday night into Monday. - Weak disturbance may bring a period of light snow Tuesday afternoon. && .DISCUSSION... KEY MESSAGE 1...Damaging southerly gusts through this afternoon as a powerful low- level jet and cold front push across the region. Drying conditions late today with strong post frontal westerly winds. A mighty low-level jet has brought damaging southerly gusts across the region late this morning and these conditions will continue into early afternoon. Wind gusts have ranged between 45 and 65 MPH across much of southern New England. But a few notable gusts include; the Blue Hill Observatory with a gust of 72 MPH and a gust of 82 MPH at the Southeast Lighthouse on Block Island. This system is quickly exiting the region, the core of the jet shifting east of Cape Cod between 2 PM and 4 PM this afternoon. High Wind Warnings for coastal areas of RI/MA and the coastal plain remain in effect through early this afternoon. Areas under the warning will convert to an advisory for post frontal winds that are driven by strong cold air advection. BUFKIT forecast soundings indicate deep mixing of the boundary layer which could extend to 850mb, where winds are 35 to 45 knots. With the steep low-level lapse rates, should be able to transfer a fair amount of the energy to the surface this evening through sunrise on Saturday morning, winds quickly diminish there after. Have extend the Wind Advisory through due to the ongoing wind threat. Gusts for tonight will not be as intense, but are still blowing 35 to 50 MPH from the west. That said, gusts up to 60 MPH are possible for the highest terrain of eastern Berkshires and northern Worcester Hills, but didn`t have enough confidence to issues a High Wind Warning here. As for precipitation, this is wrapping up early this afternoon with a brief change over to snow showers possible as the CAA develops. Otherwise, drying conditions overnight, PWATs fall from 1.3" to less than 0.3". And as for temperatures, fall from the 50s this afternoon through the 20s overnight. Given the strong winds overnight, this should help to dry out the ground and limit any formation of black ice. KEY MESSAGE 2...Quiet conditions Saturday and Monday, with Sunday featuring the potential for additional strong wind gusts. High-pressure briefly returns Saturday with easing winds, sunshine, and seasonable temperatures. While dry conditions likely continue on Sunday, a developing low pressure system moves across Quebec and the trailing cold front extending into southern New England. Another day with gusty winds, starting from the southwest and going northwest. Winds aloft are 40 to 60 knots, don`t think as much wind transfers to the surface on the southwest wind direction, but when wind shift to northwest with the CAA, gusts should develop between 35 and 45 MPH. Mainly dry period, outside of an upslope snow shower across the far western areas of MA. Monday, 1035mb high-pressure sets up to the southwest with dry and chilly conditions expected. KEY MESSAGE 3... Shortwave brings a period of gusty winds and much colder air Sunday night into Monday A mid-level shortwave trough moves through late Saturday into Sunday bringing scattered rain and snow showers mainly across far northern Massachusetts. The larger concern will be for another period of elevated winds especially Sunday night into Monday. Continuing to see two periods of strong low level winds Sunday and Monday. First will be early Sunday morning as a southwest low level strengthens to 40-50 mph as warm air advection increases. Limiting factor will timing as the core of the jet passes through between 06-12z. There will still be locally better mixing (lapse rates between 4-6 C/km) at coastal locations and across the elevated terrain. These areas could winds gust as high as 40-45 mph thru 12z Sun. Another round of more widespread gusty winds arrives later Sunday behind a strong cold front. Strong mid and low level cold air advection will help to mix a 40-55 mph low level jet to the surface. Expecting widespread gusts of 40-45 mph from 00z-15z Monday. Additional concern for Monday will be a significantly colder airmass Monday. Temps at 850mb plunge to around -15C which should translate to low temperatures ranging from the mid teens in the interior to the mid 20s for the Cape and Islands. These cold temps paired with strong NW winds push wind chill temperatures down into the lower single digits in elevated interior areas and lower to middle teens elsewhere. KEY MESSAGE 4... Weak disturbance may bring a period of light snow Tuesday afternoon. By Tuesday an upper level disturbance over northeast Quebec helps form a weak surface low near the international border. Guidance shows a broad area of warm advection on the southern side of the low as it moves southeast. Forcing from the warm advection could be enough for widespread snow showers/light snow Tuesday into Tuesday afternoon. Latest NBM shows a light event with probabilites of greater than 1 inch of accumulation Tuesday generally below 30 percent and confined to the higher elevations of Massachusetts. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 18z TAFs: High confidence (60%). Strongest S winds with gusts to 40-50kt will persist through 21z before winds shift to W/SW and subside a bit as cold front approaches. LLWS will remain an issue with 020 winds 40-60kt except 70-75kt along coastal areas. Another surge of 35-45kt gusts expected tonight as colder air arrives. W/NW winds gradually diminish overnight and Sat. MVFR/IFR conditions persist through late afternoon in -SHRA, and we may see a change to -SHSN across western/central MA this evening but no accumulation. VFR later this evening through Sat night. KBOS Terminal...High confidence in TAF. Strongest gusts through 21z with LLWS. KBDL Terminal...High confidence in TAF. Strongest gusts through 21z with LLWS. Outlook /Sunday through Wednesday/... Sunday through Monday: VFR. Windy with gusts up to 35 kt. Monday Night: VFR. Chance SN. Tuesday: MVFR/IFR conditions possible. Breezy. SN likely, chance RA. Tuesday Night: Mainly VFR, with local MVFR possible. Breezy. Slight chance RA. Wednesday: VFR. Breezy. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Today through Saturday Night...High Confidence. Storm Warnings are in effect through 3 PM this afternoon, westerly Gale Force conditions are expected to continue into Saturday morning. Seas will build to near 15 ft on the outer waters. Winds briefly drop off later this afternoon as the low level jet moves to the east, then another pulse of 35-45 kt gusts from the W develops tonight behind the cold front. Winds will quickly diminish through the day Saturday with subsiding seas. Outlook /Sunday through Wednesday/... Sunday through Sunday Night: Strong winds with gusts up to 35 kt. Rough seas up to 10 ft. Monday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Monday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of snow. Tuesday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. Rain likely, chance of snow. Local visibility 1 to 3 nm. Tuesday Night: Strong winds with gusts up to 35 kt. Areas of rough seas. Chance of rain. Wednesday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Wind Advisory until 1 AM EST Saturday for CTZ002>004. MA...Wind Advisory until 1 AM EST Saturday for MAZ002>006-008>014- 017-018-026. High Wind Warning until 3 PM EST this afternoon for MAZ007- 015>024. RI...Wind Advisory until 1 AM EST Saturday for RIZ001>003. High Wind Warning until 3 PM EST this afternoon for RIZ002- 004>008. MARINE...Storm Warning until 3 PM EST this afternoon for ANZ230>236-251. Gale Warning until 7 AM EST Saturday for ANZ237-256. Storm Warning until 4 PM EST this afternoon for ANZ250-254-255. && $$