Area Forecast Discussion

981 FXUS61 KBOX 042342 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 742 PM EDT Thu Jun 4 2026 .WHAT HAS CHANGED... Continue to refine summery temperatures and timing of precipitation along with the risk for thunderstorms (some could be severe) for this coming weekend. && .KEY MESSAGES... - Quiet and dry through the rest of the work week into much of Saturday with unseasonably warm temperatures. - Unsettled weekend with late day to nighttime showers and thunderstorms (some could be strong), and another round of scattered showers and sub-severe storms Sunday afternoon. - Dry weather with cooler onshore flow through the early next week, but turning more summerlike by midweek. && .DISCUSSION... KEY MESSAGE 1...Quiet and dry through the rest of the work week into much of Saturday with unseasonably warm temperatures. Not much has changed short-term from the previous forecast. Unseasonably warm temperatures continue as mid level ridging builds in over the northeast and surface high pressure remains affixed over much of the eastern US, centered over the SE US. 925 mb temperatures over southern New England continue to sit around 20C and climb slightly above it heading into Friday. By Saturday morning, they could reach 23C. Dewpoints Friday mostly remain in the upper 40s/low 50s, increasing overnight heading into Saturday. Spots along the south coast could reach dewpoints in the upper 50s and even to 60F by Saturday morning, setting the stage for a more uncomfortable, humid heat compared to the days prior. Highs will climb into the low 90s across southern New England tomorrow and Saturday, with slightly cooler temperatures in the upper 80s along the immediate coasts Friday; local seabreezes may provide this bit of relief. Temperatures tonight could still get to the low 50s in the usual radiational cooling spots as winds go light. Some patchy fog could develop in those spots too, especially in SE MA. High clouds move in overnight continuing into Friday, but these should be high enough to not have much effect overnight. KEY MESSAGE 2...Unsettled weekend with late day to nighttime showers and thunderstorms (some could be strong), and another round of scattered showers and sub-severe storms Sunday afternoon. A slow-moving cold front over interior northern New England associated with a positively-tilted 500 mb trough over the Gt Lakes will slowly trudge eastward into the warm airmass in place. This feature looks to bring an increasing risk for showers and thunderstorms Saturday. Given that the front`s orientation runs nearly parallel to the 500 mb height contours, odds favor a slow- moving frontal boundary. Currently the timing looks to be more centered late in the day Saturday and Saturday night, but ultimately the timing of the front will be critical on how strong any thunderstorms may become. Still, with mid-level lapse rates running around 6.5 to 7 C/km, a risk for thunderstorms could linger well into the night. A few storms could become strong with brief heavy downpours and localized straight line wind damage being the main risks, with the best chance being in interior Southern New England, but some risk for sub-severe storms could linger into the evening. This cool front then moves towards and offshore the South Coast toward the pre-dawn hours. For Sunday...we`ll probably have residual subsidence and mostly cloudy, somewhat humid and generally dry weather to begin the day into at least a part of the morning hours. Another round of showers and embedded thunderstorms then develops along a secondary, backdoor frontal boundary moving southward from VT/NH, starting around early to midafternoon and tending to be a little more concentrated in central and eastern portions of Southern New England. With weak winds aloft, the risk for severe weather with this second round of showers and storms looks low. Temps on Sunday look quite a bit cooler in the 70s to lower 80s, but it will still feel a little humid but not oppressively so. Once the secondary/backdoor front moves offshore, this will bring about a cool onshore NE flow with lots of low clouds and cooler temps (lows in the lower 50s). We do really need the rain, but that`s offset by the idea that there are several outdoor events happening this weekend. There is still some uncertainty in the timing, but as it stands right now: it looks as though much of the daytime hours Saturday end up being warm and somewhat humid but generally dry, but the risk for showers and storms increases late in the day and into the nighttime hours. The better potential for storms becoming strong in this timeframe. Additional showers and storms develop starting early Sunday afternoon, and while the risk for severe weather is even lower with this round, there could be a pretty generous coverage of storms around. KEY MESSAGE 3...Dry weather with cooler onshore flow through the early next week, but turning more summerlike by midweek. Amplified weather pattern develops with a large mid/upper level ridge extending from the Gulf Coast northward all the way to the southern shores of Hudson Bay in Canada. 850 mb temps in the mid to upper teens Celsius are associated with this amplified ridge. At least for the first few days early next week, we`ll be shielded from these very warm temps as onshore flow prevails with mostly sunny conditions. Although the timing is unclear, eventually the amplified ridge and warmer air aloft comes in around midweek, and with that comes a return to summerlike temps in the 80s to low 90s. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 00z TAF Update: Tonight Through Friday Night: High confidence. VFR through the period. Westerly winds around 5-10 kt generally govern through most of Friday, though will have seabreezes along the eastern MA coast starting around 15z Friday, then kicking out to an offshore/SW wind by 00z Saturday. Winds Friday night become WSW/SW around 5-10 kt. KBOS...High confidence in TAF. KBDL...High confidence in TAF. Outlook /Saturday through Tuesday/... Saturday: VFR. Breezy. Chance SHRA. Saturday Night: VFR. Breezy. SHRA likely, slight chance TSRA. Sunday: Mainly VFR, with local MVFR possible. Chance SHRA, chance TSRA. Sunday Night: Mainly VFR, with local IFR possible. Breezy. Chance SHRA. Monday: VFR. Breezy. Monday Night: VFR. Tuesday: VFR. Breezy. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Through Friday Night...High confidence. Marginal SCA winds remain possible over Buzzard`s Bay, Vineyard Sound, and Nantucket Sound through the rest of this afternoon. Otherwise, seas remain between 2-4 ft through Friday night. Winds Friday will likely be similar to today`s setup, but winds over Buzzard`s Bay and the aforementioned areas from today`s elevated winds should remain just below Small Craft Advisory criteria. If criteria winds do develop among the SW winds tomorrow, it should be marginal. Across the rest of the waters, winds up to 20 kt are possible through this evening, then all should remain at or below 15 kt tomorrow and tomorrow night. Outlook /Saturday through Tuesday/... Saturday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Saturday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Chance of rain showers, slight chance of thunderstorms. Sunday: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain showers, slight chance of thunderstorms. 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: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Slight chance of rain showers. Monday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Tuesday: Winds less than 25 kt. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 9 PM EDT this evening for ANZ232>234. && $$ DISCUSSION...Loconto/Hrencecin AVIATION...Loconto/Hrencecin MARINE...Loconto/Hrencecin NWS BOX Office Area Forecast Discussion