AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 140 AM EDT Thu Mar 19 2026 .WHAT HAS CHANGED... Increased southwest winds and wind gusts Friday afternoon and Friday night. Otherwise, no significant changes to the forecast. && .KEY MESSAGES... - Mix of sun and clouds with more clouds in western New England today, with temperatures closer to seasonable. - A frontal system brings milder temperatures but increasing clouds and breezy southwest winds Friday. Rain develops late in the day Friday into Friday evening, although rain amounts will not be significant. - Breezy and unsettled through early next week. Another round of showers Sunday night into Monday. Cooler temperatures expected Monday through mid-week. && .DISCUSSION... Key Message 1...Mix of sun and clouds with more clouds in western New England today, with temperatures closer to seasonable. High pressure remains anchored off Georges Bank early this morning, although to the west is a deamplifying, weak Clipper system moving through northern NY. This weak system is already generating a pretty large degree of cloud cover in central NY, and the leading edge of high clouds was impinging into interior Southern New England. Today could be best described as a mix of sun and clouds to go along with dry weather, with more sun the further southeast one goes closer to the surface high pressure. A light SE wind should prevail to go along with local sea and bay breezes for the eastern MA and Narragansett Bay areas, helping to keep these areas slightly cooler. Temperatures on the whole should run closer to normal than yesterday, but still should clock in a couple degrees cooler than typical mid-March normals in the low to mid 40s (with upper 30s along the coasts). Key Message 2...A frontal system brings milder temperatures but increasing clouds and breezy southwest winds Friday. Rain develops late in the day Friday into Friday evening, although rain amounts will not be significant. A more robust surface frontal system will then dig southeast from Ontario in prevailing WNW flow aloft Friday. This system will be associated with a pretty strong burst of warm and moist advection driven by an 850 mb SW jet of 45-50 kt. Mostly sunny conditions should prevail at least during the morning hours. As cloud cover starts to increase later Friday morning into Friday afternoon, SW winds will also be increasing. Noting 950 mb SWly jet of 35-40 kt, although mixing looks shallow. It turns into a pretty breezy afternoon with speeds around 10-15 mph and gusts in the 25 to 35 mph range, with the higher end of that range more confined to Cape Cod and the Islands which typically gusts pretty well with SW flow (tempered by the cooler water temps). Highs should reach into the low to mid 50s in most areas, though upper 40s over the south coast, Cape and Islands due to persistent SW flow over the waters. Best chance for rains takes place during the evening, as the front slowly trudges southeastward through Southern New England into the southeast waters. This will also lead to decreasing SW wind gusts. As it does so, it will act on a modest PWAT plume increasing to around 0.75 inches, which is really not that impressive. Bumped PoPs up to high Likely to lower Categorical, although this doesn`t look to be a significant precip-maker, with ensemble QPF probs still indicating low (< 30%) probs of rainfall totals greater than 0.50". Given stable thermodynamics and only modest PWATs to work with, the rainfall probs seem reasonable. May have to watch for a slowing frontal zone though, as the orientation of the front becomes nearly parallel to the 500 mb height contours, which could result in lingering showers into early Saturday morning. Key Message 3...Breezy and unsettled through early next week. Another round of showers Sunday night into Monday. Cooler temperatures expected Monday through mid-week. A few residual showers are possible earlier in the day Saturday otherwise most areas remain dry. High temperatures Saturday likely range in the 50s with mid-50s possible for interior areas. Sunday trends a degree or two warmer with potential for a few locations to hit 60. Next round of showers arrives late Sunday into Monday ahead of a shortwave trough moving across the Great Lakes. A plume of rich moisture accompanies this wave, supporting more widespread showers. Across ensemble guidance, the majority of members show QPF in the .20" to .55" range and less than an inch in the 90th percentile. Seeing no signal for heavy rain. A cooler airmass moves in early Monday. Depending on the timing of the colder air, this may allow some light snow to mix across the higher elevations. Any accumulations would be a trace to a few tenths, so no impacts expected. Drier air moves in Monday, but can`t rule out an isolated shower during the day. Temperatures trend cooler with highs in the 40s. Ensemble means generally signal for a period of drier conditions Tuesday through mid-week, with the next chance for precipitation arriving Thursday. Temperatures remain cooler than normal through mid-week. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 06z TAF Update: Through 12z Thursday: High confidence. Mainly VFR. SCT-BKN 040-060 decks move into BDL after 07z. The one area that could see SCT-BKN MVFR decks is across HYA and ACK after 08z with shallow marine moisture returning on SE flow. That could lurk offshore of Boston Harbor but may not directly impact the terminal. SE to S winds under 10 kt. Today: High confidence overall. Mainly VFR, with any MVFR that developed off the eastern coast lifting to VFR bases. SE winds around 5-10 kt (potentially ESE at BOS), coming around to southerly late. Tonight: High confidence. VFR, though with lower-end VFR/borderline MVFR at BDL. S to SW winds 5-10 kt. Friday: High confidence. VFR. SW winds increase to around 10-15 kt with gusts to around 25-30 kt. Potential for low level wind shear as well. KBOS Terminal...High confidence in TAF, though moderate on wind directions today. SE winds develop again with high confidence today but still some uncertainty if they become 120-130 degrees or if they stay within the 150-160 degree range. Winds become S late in the day. KBDL Terminal...High confidence in TAF. Outlook /Friday through Monday/... Friday: VFR. Windy with gusts up to 30 kt. Slight chance RA. Friday Night: MVFR/IFR conditions possible. Windy with gusts up to 30 kt. RA likely. Saturday: VFR. Breezy. Saturday Night: VFR. Sunday: VFR. Breezy. Chance RA. Sunday Night: Mainly VFR, with areas MVFR possible. Breezy. Chance RA, chance SN. Monday: Mainly VFR, with local IFR possible. Breezy. Chance SN, slight chance RA. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Winds and seas will remain below marine headline thresholds through Thursday night. SE winds today around 10-15 kt to shift to S and then SW tonight into early Friday. Seas 4 ft or less on all waters. Marine headlines are likely to be needed Friday afternoon into Friday evening as a frontal system increases SW winds. Some wind gust guidance supports gusts to near gale force, although the mixing depth looks shallow over the cooler marine boundary layer which could lend itself to gusts more into the 25-30 kt range. Later shifts could consider Gale Watches, but thinking this situation could be handled with SCAs. Rainy conditions could also reduce visibility some Friday evening. Outlook /Friday through Monday/... Friday: Low risk for Small Craft Advisory winds with local gusts up to 30 kt. Seas locally approaching 5 ft. Friday Night: Moderate risk for Small Craft Advisory winds with local gusts up to 30 kt. Seas up to 5 ft. Chance of rain. Saturday: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain. Saturday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain. Sunday Night: Winds less than 25 kt. Seas up to 5 ft. Rain likely. Monday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Chance of rain. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$