187 FXUS61 KBOX 042339 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 739 PM EDT Wed Jun 4 2025 .SYNOPSIS... Summer warmth Thursday and Friday with the heat peaking on Thursday as highs reach 90 to 95 away from the immediate coast. While an isolated shower/thunderstorm will be possible Thursday, there will be a much better chance of scattered showers and thunderstorms Friday some of which may linger into Saturday. Unsettled weekend once again across southern New England. Chances for showers and thunderstorms are highest Friday evening. Drier conditions expected Monday before more showers are possible heading into midweek next week. High temperatures remain primarily in the 70s and 80s across the region. && .NEAR TERM /THROUGH THURSDAY/... Key Messages... * Mild night with increasing humidity Details... Upper level ridging remains in control of our weather tonight. Humidity values increase overnight with southwesterly flow. Low temperatures will remain mild with lows falling to 60-65 degrees, especially in urban areas. && .SHORT TERM /THURSDAY NIGHT THROUGH 6 PM THURSDAY/... Key Messages... * Hot Thu with highs 90-95 away from the immediate coast * Low chance of showers and some isolated thunderstorms across NW MA * Little relief from the hot and humid conditions Thursday night Details... Thursday... Still expecting widespread heat Thursday as a strong upper level ridge builds over Southern New England. The ridge will result in plenty of sunshine with 925T rising to between +23C and +25C! Expecting temperatures to quickly warm into the lower and mid 70s Thursday morning with the onset of mixing. Hot conditions develop by the afternoon with high temperatures reaching between 90 and 95 in many locations away from the immediate coast. Urban areas will have the greatest chance of seeing 95 degree readings. There also will be a bit of humidity to the air with dewpoints in the lower to middle 60s. Heat Index Values will climb into the lower to middle 90s in many locations. While we are not anticipating any heat headlines...our experimental NWS Heat Risk product indicates moderate impacts for most individuals sensitive to the heat. While mainly dry and hot weather will be the story on Thu we can not rule out isolated showers/t-storm or two. Expecting somewhat high CAPE values but the lack of forcing and a deep dry layer aloft should prevent widespread thunderstorms. The best chance will be on any subtle sea breeze boundaries or some terrain impacts/elevated heating. Again though if any activity is able to develop it will be isolated/localized with the most locales remaining dry. Thursday Night... Another warm and muggy night expected Thursday night with many locations seeing low temperatures in the middle and upper 60`s to near 70. Could see a few showers or perhaps a thunderstorm across western areas as any remnant convection from a frontal boundary to the NW makes its way east through the first half of the overnight. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... Key Messages: * Chances for showers and thunderstorms Friday through Sunday, with the highest chances Friday night * Briefly dry on Monday before rain chances return Tuesday * Highs mostly in the upper 70s and low 80s through this period, aside from Saturday Details... Friday evening looks to have the best chances for showers and some thunderstorms. The latest NAM indicates surface CAPE values ranging from 1500 J/kg to close to 3000 J/kg in some spots across the interior in the afternoon hours, although its worth noting that the flow aloft is quite weak and there is not much shear. As time goes on and CAPE decreases, the chance for some heavy downpours may increase. Ensemble means indicate PWAT values by Friday afternoon getting close to 1.6", with the ECMWF ENS showing pockets of these elevated PWAT values in western and eastern MA. Generally, NAEFS guidance has PWAT values just under 2 standard deviations above normal across the whole region, which is in agreement across the other ensembles. Latest deterministic guidance has not completely nailed down one area that could see elevated precipitation values, but this should resolve as the event gets closer. Through the weekend, the chance for showers remains. Some guidance is hinting at a brief dry period Sunday heading into Monday, particularly as weak high pressure builds in Monday, but there`s higher confidence in a drier Monday than sometime Sunday at this time. Rain chances and elevated surface moisture make a return Tuesday through Wednesday morning with the weakening of Monday`s high pressure and rain associated with a frontal passage from a low moving NE across Canada. In terms of temperatures, highs across southern New England are expected to remain in the upper 70s and low to mid 80s across the period, aside from Saturday when highs decrease a bit to the lower 70s in some spots and generally may remain below 80. Lows are expected to generally be in the 50s and 60s. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 00z TAF Update... Through Tonight...High confidence. VFR. Winds become light to calm overnight. Some terminals that tend to see some fog could go MVFR tonight, namely BAF and ACK, but it`s not expected to last very long. Tomorrow into Tomorrow Night...High confidence. VFR. SW winds 5-10 kts across southern New England with late morning seabreezes at coastal terminals around 15z. Very low risk for isolated showers/thunderstorms in the afternoon, primarily in NW MA. BOS TAF...High confidence in TAF. BDL TAF...High confidence in TAF. Outlook /Thursday Night through Monday/... Thursday Night: VFR. Breezy. Slight chance SHRA. Friday: Mainly VFR, with local MVFR possible. Chance SHRA, chance TSRA. Friday Night: Mainly VFR, with local MVFR possible. Chance SHRA, slight chance TSRA. Saturday: Mainly VFR, with areas MVFR possible. SHRA likely, slight chance TSRA. Saturday Night: Mainly VFR, with local MVFR possible. Chance SHRA. Sunday: VFR. Chance SHRA. Sunday Night through Monday: VFR. Slight chance SHRA. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Today through Thursday...High confidence. Upper level riding persists and keeps conditions below small craft advisory overnight through Thursday. Breezier southwest winds develop Thursday night and Friday which could lead to some choppy seas. Outlook /Thursday Night through Monday/... Thursday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Friday through Friday Night: Winds less than 25 kt. Slight chance of rain showers. Saturday through Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers. Sunday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers. Monday: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Air Quality Alert until 11 PM EDT this evening for CTZ002>004. MA...Air Quality Alert until 11 PM EDT this evening for MAZ009-011. RI...None. MARINE...None. && $$ SYNOPSIS...Hrencecin/FT NEAR TERM...FT SHORT TERM...FT LONG TERM...Hrencecin AVIATION...Hrencecin/FT MARINE...Hrencecin/FT