435 FXUS61 KBOX 260820 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 420 AM EDT Sat Jul 26 2025 .SYNOPSIS... Showers and areas of severe thunderstorms continue this afternoon with a cold front. Cooler and mainly dry Saturday with showers and thunderstorms returning for Sunday. Outlook for early next week shows summerlike warmth and humidity, with generally dry weather for the majority of the time. Showers and thunderstorms return for Sunday. Outlook for early next week shows summerlike warmth and humidity, with generally dry weather interrupted by a few shots at scattered showers and thunderstorms, mainly Tuesday and late Wednesday into Thursday. Trending drier and cooler Friday into the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Key Messages: * Dry conditions and cooler today Details: Behind Friday`s front, high pressure shifts east over the region bringing in a dry airmass and generally light easterly component flow. Temperatures will be considerably cooler in the post-frontal airmass with 850mb temperatures 5-8 degrees cooler than Friday. This will equate to high temperatures in the 80s across the interior with some upper 80s possible in the valleys. E/SE onshore flow will keep the immediate coastal areas cooler today with highs in the upper 70s to around 80. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... Key Messages: * Showers and a few embedded thunderstorms return on Sunday. Severe weather is not expected at this time. * Pockets of localized heavier rainfall possible in any embedded thunderstorms. Tonight: A warm front approaches the region tonight ahead of our next approaching system. This will increase cloud cover as the night wears on. Low temperatures will be seasonable in the mid 60s. Sunday: Unsettled weather returns for Sunday as a weak shortwave trough moves through the quasi-zonal mid-level flow. Weak synoptic ascent will be accompanied by a plume of above normal moisture (150-170% of normal) to support increased cloudiness and precipitation. Given the limited upper level support, instability will be marginal/limited which reduce the risk for severe weather. Given marginal elevated instability, can`t rule out a few embedded convective showers or thunderstorms. For timing, HREF guidance shows the most likely window for rain arriving between 6AM and 11AM (little later for Cape) spreading from west to east. Can`t rule out scattered showers before the main bulk of precipitation arrives which has been hinted at by individual CAMs, but with varying timing. High resolution guidance shows precipitation exiting mid-late afternoon with some showers lingering over the Cape/Islands in the early evening. The presence of above normal moisture and marginal instability does raise some risk for pockets of locally heavy rainfall in any embedded thunderstorms. Model guidance hints at better forcing mainly north of southern New England; however, it may position close enough to bring additional lift/instability for more moderate to heavy rainfall. HREF PMM means highlight western MA in particular for higher amounts of rainfall with some isolated 1-1.5" bullseyes. Overall, we`ll interpret this as a general signal for seeing a higher probability for locally heavier amounts. Across ensemble guidance, means show a range of QPF from 0.10"-1.0" with again the higher range of amounts across western MA. Rain and cloudiness will result in a cooler day with highs in the && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Key Messages: Key Messages... * Showers and a few embedded thunderstorms return on Sunday. Severe weather is not expected at this time. * Temps warm up into the 90s through mid week but cooler weather arrives late week into the weekend. * Mostly dry this week with a chance of showers and t-storms around Tuesday and late Wed/Thu. A mid-level ridge pushes east into the region Monday which will start the week off dry. 850mb temperatures warm back up to around 18- 20C again trending temperatures back up from the weekend. Highs will likely range in the upper 80s to low 90s for the interior while the coastal areas will stay cooler in the low to mid 80s from sea breezes. Ensemble guidance shows anomalous temperatures sticking around Tuesday and potentially into Wednesday to some extent. Tuesday, a weak shortwave trough moves through the flow aloft which will bring isolated to scattered showers and thunderstorms in the afternoon. Ensemble guidance shows a more substantial wave moving through in the Weds-Thurs timeframe. Still uncertainty in the details such as timing, precipitation chances/amounts. What makes this wave also more substantial aside from increased precipitation chances will be the cooler airmass pushing in behind it. This will break the above normal temperatures from earlier in the week. Ensemble guidance shows good agreement with a transition to even below normal temperatures by Friday. This airmass will feel almost Fall-like! We are a little far away for any tinier details, but trends show potential for highs in the 70s by Friday. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 06Z Update: Through 12z: High Confidence. Ceilings are generally VFR. Still can`t rule out a brief period of BR for the Cape and Islands early this morning as there is still some residual moisture/clouds lingering. Dry air should clear any residual patchy fog by 12z. Saturday: High Confidence. VFR with upper level clouds arriving throughout the afternoon. Winds start NNE this morning then turning more easterly in the early-late afternoon. Speeds 5-8 kts for the interior and 6-12 kts closer to the coast. There may be a brief period of light VRB winds at the interior terminals (BDL, BAF, ORH) early afternoon. Saturday Night: High Confidence VFR. Light SE at 5-8 kts winds early evening become light SSW by midnight. Rain should begin to move in across southern New England from west to east after 08z. Mid-level ceilings push across region ahead of the showers. Sunday: Mainly mix of low end VFR to MVFR as rain moves across southern New England on Sunday. S/SSW winds 8-13 kts. KBOS terminal...High confidence. KBDL terminal...High confidence. Outlook /Sunday Night through Wednesday/... Sunday Night: Mainly VFR, with local MVFR possible. Chance SHRA. Monday through Tuesday Night: VFR. Wednesday: VFR. Slight chance SHRA, slight chance TSRA. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Through Sunday...High Confidence. NNE/NE winds at 10-15 kts this morning, closer to 20 kts for the southern waters. Gusts around 25 kts this morning. This should be short-lived as wind speeds trend downward after 12z becoming light E in the afternoon 8-12 kts. Winds veer SSW Saturday evening. Rain expected Sunday with S/SSW winds 10-15 kts. Gusts up to 20 kts for the norther outer water. Outlook /Sunday Night through Wednesday/... Sunday Night: Winds less than 25 kt. Chance of rain showers, slight chance of thunderstorms. Monday through Wednesday: Winds less than 25 kt. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ SYNOPSIS...Mensch NEAR TERM...Mensch SHORT TERM...Mensch LONG TERM...Mensch AVIATION...Mensch MARINE...Mensch