AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 206 AM EST Thu Dec 25 2025 .WHAT HAS CHANGED... Chances for accumulating snowfall increased Friday night into Saturday despite lower-than-normal forecast confidence. && .KEY MESSAGES... - Breezy with isolated rain/snow showers today. Temperatures fall quickly below freezing this evening with wind chill values near or below zero overnight. - Accumulating snow possible Friday night into Saturday morning. Uncertainty remains high, but the best chance for plowable snow is in western CT/MA. - Storm system around Sunday night into Monday could bring accumulating wintry mix (sleet/freezing rain) to rain. && .DISCUSSION... KEY MESSAGE 1... Breezy with isolated rain/snow showers today. Temperatures fall quickly below freezing this evening with wind chill values near or below zero overnight. Northern stream shortwave drops out of northern New England this morning, with a reinforcing cold front following behind this afternoon. This could lead to a few isolated snow showers this morning into the early afternoon before drier midlevel air arrives with the cold front. No snow accumulation are expected with these snow showers. Winds ahead of the cold front this morning will be light southwesterly, allowing high temps to top out near 40F. Temperatures behind the cold front drop quickly, falling below freezing by 5-6 pm tonight. Winds also increase behind the cold front, gusting 25-35mph, starting this afternoon and lasting through the night. The gusty winds will bring the wind chill index down to near or below zero overnight. Decreasing winds and cold Friday with highs in the low to mid 20s across the region. KEY MESSAGE 2...Accumulating snow possible Friday night into Saturday morning. Uncertainty remains high, but the best chance for plowable snow is in western CT/MA. A positively tilted shortwave and associated surface low drops out of the Great Lakes on Friday and moves towards the Northeast for Friday night into Saturday. 00z guidance didn`t make the track of this system any clearer as global guidance sources of the GFS and Canadian keep the southerly track through PA and into southern NY, while the NAM swung for the fences and takes this system through central NY and into SNE. The EURO also shifted the track slightly to the north, but not to the extent of the NAM. Given the large spread in the low-pressure track, confidence in snow accumulation remains low. The best chance for plowable snow accumulation remains in SW CT, where Ensembles show a 50% probability of 3 inches of snow, dropping to 10-20% in eastern MA. Hi-res guidance only adds to the uncertainty at this time, as it still favors a more southern track (outside the Nam-3k), with dry air shutting out most of SNE. KEY MESSAGE 4...Storm system around Sunday night into Monday could bring accumulating wintry mix (sleet/freezing rain) to rain. In the wake of the Fri night/Sat system, the lower-level airmass warms substantially and by Sun night brings 850 mb temps in the +4 to +6C range. Models show a more potent and moisture- laden low pressure embedded in SWly flow aloft which looks to track to our north and west Sun night, with some potential for secondary low development based on some bagginess in sea-level isobars Mon. The strength of the lower-level warmer air as mentioned above would instead favor sleet/freezing rain at least at outset in most areas Sun night, and then gradually transition to plain rain; timing of which varies depending on how quickly surface temps from Sunday night can modify. We typically keep precip types simple (rain or snow) at this extended range, but felt there was enough confidence in the warm nose aloft to indicate wintry mix in the forecast. Too early for specifics on accums at this range but the potential for an accumulating ice event is possible in most areas, but especially so for interior SNE N/W of I-95 which often struggles to scour out colder air as quickly as blended models depict. && .AVIATION /07Z THURSDAY THROUGH MONDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Today...High Confidence VFR. Slight chance for some rain/snow showers over BOS and Cape/Islands tomorrow morning. Showers may be accompanied by brief periods of MVFR vsbys/cigs. Greatest risk would be 12-18Z. Southwest winds to start, but shifting to northwest after 18Z with 25-30 knots gusts likely. Tonight...High Confidence VFR. Gusty northwest winds. KBOS Terminal...High confidence VFR. Low chance for a isolated snow shower in the morning. Brief MVFR CIGS would accompany any snow showers. Winds shift NW in the afternoon and gust up to 30 knots. KBDL Terminal...High confidence in TAF. VFR. Winds shift NW in the afternoon and gust up to 25 knots Outlook /Friday Night through Monday/... Friday Night: Mainly VFR, with local IFR possible. Chance SN. Saturday: Mainly VFR, with local MVFR possible. Chance SN. Saturday Night: VFR. Sunday: VFR. Slight chance RA. Sunday Night: Mainly VFR, with local IFR possible. Breezy. RA, SN likely. Monday: Mainly MVFR, with areas IFR possible. Windy with local gusts up to 30 kt. RA. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Christmas Day through Friday Increasing SW winds this morning, turning NW this afternoon with gusts of 25-35 knots lasting until daybreak Friday. Seas remain rough today, at 7-10 feet offshore and 3-5 feet near shore and in the sounds. Winds on Friday become light northwesterly at 10-15 knots, with seas decreasing to 2-5 feet. Outlook /Friday Night through Monday/... Friday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of snow. Local visibility 1 nm or less. Saturday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of snow. Saturday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Sunday: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain. Sunday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Rain likely. Monday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Rain. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory from 10 AM this morning to 7 AM EST Friday for ANZ230-236. Gale Warning from 4 PM this afternoon to 7 AM EST Friday for ANZ231-232-250-251-254>256. Small Craft Advisory from 7 AM this morning to 7 AM EST Friday for ANZ233>235-237. && $$