Area Forecast Discussion
Issued by NWS Boston, MA

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253 FXUS61 KBOX 020636 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 236 AM EDT Wed Jul 2 2025 .SYNOPSIS...
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Warm but a bit less humid today and Thursday, then drying out with more seasonable temperatures heading toward Independence Day. An upper level disturbance may bring scattered showers and thunderstorms Thursday, otherwise dry through the end of this week. Heat and humidity return late this weekend into early next week.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Key Messages... * Warm today with drier air working in from the north. The best chance for some showers or thunderstorms is along and adjacent to the south coast. As the mid level trough axis slowly shifts east early this morning we`ll continue to see the plume of deepest moisture slowly drop south. However, the cold front moving into western MA/CT early this morning will eventually become stationary today, draped across SNE from SW to NE. This prolongs the time that the deepest moisture (PWATs still near 2 inches) lingers over the south coast. Cloudcover remains quite thick much of the day, but northwest MA will be the first to see increasingly sunny skies this afternoon, expanding slowly southeast. Meanwhile, low stratus clouds likely linger over the southeast coast much of the day, even expanding further inland to cover much of the coastal plain overnight before the front finally pushes through a clears skies for everyone by Thursday morning. Besides additional clouds, the moisture combined with broad lift from a nearby upper jet will be enough for some scattered, unorganized showers, mainly south of the MA pike, but especially along the immediate coast. Some garden variety thunderstorms are also possible given temps in the 70s/80s and dewpoints in the 70s will lead to MUCAPE values of 500-1000 J/kg. Lows drop into the 60s for most overnight, but into the 50s in northwest MA where drier air is in place.
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&& .SHORT TERM /THURSDAY/...
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Key Messages... * Very warm Thu but with less humidity than the previous several days. Scattered showers and thunderstorms possible. Thursday brings with it the last very warm day before a bit of a cool down to more seasonable temperatures. Plenty of sun is expected and temperatures will rise well into the 80s, even low 90s for the hottest spots thanks in part to downslope warming on westerly flow. Dewpoints will be in the upper 50s/low 60s, yet will still be able to achieve CAPE values over 1000 J/kg. A mid level trough axis approaches as a surface cold front swings through kicking off scattered showers and thunderstorms, some of which could be strong to severe. Parameters look better than Tuesday, with 0-6 km bulk shear of 35-40 kts, low level lapse rates of 7.5-8.5, and mid level lapse rates of 6-6.5. This would lend to a risk for severe hail and damaging winds. We`ll have to see if the timing of the front can line up well to capitalize on the peak diurnal heating/instability. The best chance of severe weather is in the interior. For now all of SNE is under a marginal (level 1 of 5) risk of severe weather.
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&& .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
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Key Messages... * Sunny with drier air for Independence Day and into the weekend. * Heat and humidity return Sunday into next week. Quiet weather returns just in time for the Independence Day holiday and holiday weekend. This is thanks to a surface high and mid level ridge bringing subsidence and quiet weather to the northeast. Post frontal temperatures on Friday will top out in the upper 70s to mid 80s, then we`ll see a steady increase of temperatures each day going forward. 90s return on Sunday and Monday along with higher humidity thanks to warm, moist SW flow. Another front/mid level disturbance then brings more unsettled weather around the start of the week.
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&& .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
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Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Through 12Z: Moderate Confidence. IFR-LIFR stratus and fog continues over the Cape and island terminals. VFR elsewhere with scattered -SHRA. Today: High confidence. VFR for most terminals, though IFR cigs will linger over the Cape/Islands in the morning, through the afternoon at ACK. Risk for showers will continue near the south coast, with low risk for an afternoon t-storm. Tonight: High confidence. Mainly VFR, but patchy stratus and fog will redevelop along the south coast. Thursday: Moderate confidence. VFR. A line of SHRA/TSRA will move through in the afternoon and evening. KBOS Terminal...Moderate confidence in TAF. Expect VFR to persist, except brief lower conditions in any t-storms after 21z. KBDL Terminal...Moderate confidence in TAF. VFR, but risk for SHRA/TS returns by 20z. Outlook /Thursday Night through Sunday/... Thursday Night through Saturday Night: VFR. Sunday: VFR. Breezy.
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&& .MARINE...
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Forecaster Confidence Levels... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Today through Thursday: Persistent SW flow through the period, 10-20 kt. Areas of fog developing over the waters this morning, possibly returning again tonight. Seas 3-5 ft diminish to 2-4 ft by Thursday. Outlook/Thursday Night through Sunday/... Thursday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Independence Day through Saturday Night: Winds less than 25 kt. Sunday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas locally approaching 5 ft.
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&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 9 AM EDT this morning for ANZ250- 254. Small Craft Advisory until 8 PM EDT this evening for ANZ255- 256. && $$ SYNOPSIS...BW NEAR TERM...BW SHORT TERM...BW LONG TERM...BW AVIATION...BW MARINE...BW