FXUS61 KBOX 090452 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 1252 AM EDT Thu Jul 9 2026 .WHAT HAS CHANGED... A Rip Current Statement is in effect through this evening for eastern and ocean facing beaches in Massachusetts. A Small Craft Advisory remains in effect until 8 pm this evening. && .KEY MESSAGES... - Becoming warmer with increasing humidity through the end of the work week. - Warm, humid weather returns late in the week. Scattered showers and thunderstorms possible both days but better chances looking to be on Friday. - Drier, seasonably cool and less humid weather for the weekend into early next week && .DISCUSSION... KEY MESSAGE 1...Becoming warmer with increasing humidity through the end of the work week. High pressure and mostly clear skies continue through most of Thursday. 925mb temperatures rising to near 20C and plenty of sunshine will allow for surface temperatures to begin to creep up above seasonable norms... likely near 90 across most of southern New England by Thursday. Humidity will begin to increase under broad WSW flow, with dewpoints increasing to near or just above 70 (at times) Thursday. A cold front moving through Thursday evening could bring chances for isolated to scattered showers and thunderstorms later in the night/overnight, but the highest risk currently remains in western MA. A Rip Current Statement has also been issued through this evening for eastern MA, primarily for ocean facing beaches, due to prolonged northeasterly flow and 5+ ft seas. KEY MESSAGE 2...Scattered thunderstorms along a cold front Friday afternoon to early evening. Although severe weather potential looks minimal at this time, lightning and torrential downpours are the main risks. Warm and humid weather continues into Friday to go along with partly to mostly cloudy skies. A cold front will be gradually sagging southward from northern New England during the early afternoon in northern MA and reaching the southern CT-RI-MA coastline by early evening. This will pose a better chance for scattered showers and thunderstorms to develop than compared to Thursday. The biggest uncertainties specific to the thunderstorm forecast are the degree of instability we can muster and how quickly will the front progress offshore. Both the 12z NAM and 12z GFS capture the instability envelope well, with the NAM's CAPE values around 1500- 2500 J/kg due to its high-dewpoint bias, while the GFS's overmixing bias shows considerably lower values at around 500 J/kg or less. The answer is probably somewhere in the middle; shear values are also on the lower side at around 30 kt, which should mitigate or limit any organized severe weather potential outside of water-loaded downdrafts. The main risks looks to be lightning and slow-moving heavy downpours, which could lead to instances of street flooding in areas that see repeated thunderstorms. Latest guidance indicates 700- 500 mb heights which become increasingly parallel to the southward- sagging frontal boundary, which adds to the risk for slower- moving storms and also casts some uncertainty when we clear out, with the Canadian guidance suggesting post-frontal light rains lingering into part of Saturday along the South Coast. KEY MESSAGE 3...Drier, seasonably cool and less humid weather for the weekend into early next week. Even if the cold front from Friday night takes a little bit longer to fully clear out from the South Coast, we should be trending drier by Saturday late morning. The 500 mb pattern then transitions to one of cyclonic flow/troughing in the mean, which favors cooler temperatures (low to mid 80s) and lower humidity levels than experienced for late in the week. Weekend appears favorable for outdoor plans with nice summer weather. We'll be on the far western periphery of a pretty impressive upper level ridge which latest guidance still shows reaching to nearly 600 dm building over the northern/central Plains and upper Midwest. We still might need to keep an eye on possible storminess pivoting around the ridge but it looks as though the weekend into early next week ends up drier than not. && .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: Rest of tonight...High confidence. VFR. Light and variable winds becoming southwest. Perhaps a few patches of Fog mainly along the south coast. Thursday...Moderate confidence. VFR. An isolated shower or thunderstorm is possible after 20Z across the western terminals. Thursday night...Moderate confidence. Lowering clouds moving in with areas of MVFR and possibly IFR. KBOS Terminal...High confidence. KBDL Terminal...High confidence. Outlook /Friday through Monday/... Friday: VFR. Chance SHRA, chance TSRA. Friday Night through Sunday Night: VFR. Monday: VFR. Breezy. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Through Friday Morning...High confidence. SCA conditions continue in the the coastal waters through this evening with NE wind gusts around 25 kts. Conditions improve overnight into Thursday as high pressure builds over the region. A weak front approaches the region later Thursday with showers and thunderstorms possible over the southern waters. Outlook /Friday through Monday/... Friday: Winds less than 25 kt. Slight chance of rain showers. Friday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers. Saturday through Saturday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Sunday: Winds less than 25 kt. Seas locally approaching 5 ft. Sunday Night through Monday: Winds less than 25 kt. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ DISCUSSION...Loconto/McMinn AVIATION...FT MARINE...Loconto/McMinn