Area Forecast Discussion
Issued by NWS Boston, MA
Issued by NWS Boston, MA
854 FXUS61 KBOX 110605 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 205 AM EDT Tue Aug 11 2026 .WHAT HAS CHANGED... Increased uncertainty regarding shower potential Wednesday. && .KEY MESSAGES... - Yet another very warm and humid day is expected today, followed by a gradual transition to cooler and drier conditions through the end of the work week. Much more comfortable weather is expected this weekend into early next week. - Rain chances increase during the second half of the work week as a frontal boundary settles across the region, followed by a return to dry weather for the weekend. Rain chances may increase again early next week. && .DISCUSSION... KEY MESSAGE 1...Yet another very warm and humid day is expected today, followed by a gradual transition to cooler and drier conditions through the end of the work week. Much more comfortable weather is expected this weekend into early next week. One more day of heat and humidity is on tap today, with 925mb temperatures of +20C to +23C supporting highs well into the middle to upper 80s. Dew points in the lower to middle 60s will make it feel warmer, with heat indices reaching the upper 80s to lower 90s. This will result in Moderate HeatRisk, particularly along the I-95 corridor, with those most sensitive to heat and those without adequate cooling or hydration most susceptible to impacts. The pattern begins to change Wednesday as temperatures aloft gradually cool, with 925mb temperatures falling from the lower 20s Celsius today into the teens Celsius by Friday. Dew points will follow suit, dropping from the 60s today into the 50s by late this week. The result will be a noticeably cooler and more refreshing airmass by Friday. A quasi-stationary front will be the primary driver of this transition. The front is expected to linger near southern New England late Wednesday into Thursday, keeping the region in a more unsettled pattern. As the front finally pushes offshore Friday, as a cold front, drier air will filter into the region behind it, aided by high pressure building southward from central Canada. The weekend is shaping up to be the most comfortable stretch of weather in quite some time, with highs generally in the upper 70s across interior southern New England and lower 80s along the coastal plain. Dew points in the 50s will make for much more comfortable conditions, while overnight lows fall into the 50s Saturday and Sunday nights. These pleasant conditions may continue into early next week, although the forecast becomes more unsettled by then. KEY MESSAGE 2...Rain chances increase during the second half of the work week as a frontal boundary settles across the region, followed by a return to dry weather for the weekend. Rain chances may increase again early next week. Dry weather and a good deal of sunshine are expected today, although skies may become somewhat filtered by elevated smoke from distant wildfires. Tonight, a weak system passing south of New England could produce a shower or rumble of thunder across the extreme south coast and Islands, but probabilities remain low at less than 15 percent. Wednesday remains a lower-confidence portion of the forecast. While most guidance keeps a fast-moving low pressure system south of New England, there are some notable differences in the guidance. The 00z NAM develops a robust 995 mb surface low near the Benchmark (40N/70W), while the 3 km NAM also depicts a surface low in the vicinity, though considerably weaker. AI guidance likewise maintains the surface wave south of New England. Given the overall consensus, the current forecast favors a track south of the region, with little to no precipitation expected during the day Wednesday. The forecast becomes more active Wednesday night into Thursday as a quasi- stationary front settles across the Northeast. Weak surface lows riding along the boundary will provide multiple opportunities for showers, with precipitation chances increasing from late Wednesday night through Thursday night. While periods of showers are likely, the setup does not currently favor continuous rainfall across the region. The front should finally push offshore early Friday, allowing drier air to move into southern New England as high pressure builds southward from central Canada. This will usher in the dry and much more comfortable conditions expected for the weekend. High pressure should remain the dominant feature through the weekend, supporting sunny to mostly sunny skies, low humidity, and seasonable temperatures. Beyond the weekend, the pattern becomes less settled, with increasing rain chances possible early next week as the next system approaches. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 00z Update: No significant deviations from the prior forecast. Worth noting, high-resolution guidance suggests wildfire smoke from out west may lead to hazy conditions Tuesday afternoon, though confidence is lower regarding the potential impacts on terminals. Today...High confidence. VFR. West to west-northwest winds 8 to 12 kt. Winds across Cape Cod and the Islands will be west-southwest at 10 to 12 kt, with gusts up to 18 kt. As mentioned, there is a possibility for wildfire smoke to reach southern New England this afternoon and remain elevated, likely resulting in hazy skies and, at worst, visibility reductions to 5-6SM. Tonight...High confidence. VFR. Light and variable winds. There is a low probability for a shower to impact the Islands. Wednesday...High confidence. VFR. Light westerly winds. Potential for localized sea breezes to develop along the coast, including KBOS. KBOS Terminal...High confidence. Wildfire smoke aloft possible. KBDL Terminal...High confidence. Wildfire smoke aloft possible. Outlook /Wednesday Night through Saturday/... Wednesday Night: VFR. Thursday: VFR. Breezy. Chance SHRA, isolated TSRA. Thursday Night: VFR. Slight chance SHRA. Friday: VFR. Breezy. Slight chance SHRA. Friday Night through Saturday: VFR. Breezy. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Through Wednesday...High confidence. No significant weather expected through this period, with winds and seas remaining below advisory criteria. Winds today will be west to southwest, gusting at times to around 20 kt, especially across the waters south of Rhode Island toward Buzzards Bay and Vineyard Sound. Elsewhere, winds will be 10 to 15 kt. On Wednesday, localized sea breezes may develop near shore, while offshore winds remain variable at less than 10 kt. Seas will remain below 3 ft throughout the forecast period. Outlook /Wednesday Night through Saturday/... Wednesday Night: Winds less than 25 kt. Thursday: Winds less than 25 kt. Slight chance of rain showers, isolated thunderstorms. Thursday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers. Friday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers. Friday Night: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of seas approaching 5 ft. Saturday: Winds less than 25 kt. Seas locally approaching 5 ft. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ Dooley