FXUS61 KBOX 240538 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 138 AM EDT Mon Aug 24 2026 .WHAT HAS CHANGED... Updated Aviation section. && .KEY MESSAGES... - Outside a few showers/isolated t-storm risk into mid evening with the focus across the interior especially near and west of the CT River Valley. Areas of fog develop overnight which may become locally dense in spots. - Drier with a return to seasonable temperatures this week. Rain chances return Thursday/Friday. && .DISCUSSION... KEY MESSAGE 1...Outside a few showers/isolated t-storm risk into mid evening with the focus across the interior especially near and west of the CT River Valley. Areas of fog develop overnight which may become locally dense in spots. The main cluster of showers that resulted in brief heavy rain along with a rumble or two of thunder has exited the eastern Ma coast earlier this afternoon. Behind this activity some subsidence and drier mid level air was allowing the lower clouds to begin to mix out from southwest to northeast. We will see a late rise in temps through early evening well into the 70s to perhaps near 80 in the CT River Valley as some peeks of sun try to develop. This will result in some modest instability developing with ML Capes approaching 1000 J/KG across parts of the interior. However...subsidence behind the earlier shortwave coupled with the main forcing well to our west will limit the additional risk. Nonetheless...a few showers and perhaps an isolated t-storm or two will be possible into mid- evening. The main focus for this activity will be across the interior and especially near and west of the CT River Valley closer to the upper level shortwave. Otherwise...the main story later tonight will be for the development of fog some of which may become locally dense. Winds become light/calm overnight coupled with partial clearing, wet ground and dewpoints remaining in the 60s will set the stage for fog development. Some of the fog may become locally dense too. Low temperatures overnight will drop into the middle to upper 50s in the outlying locations...to the middle 60s in the urban heat islands of downtown Boston/Providence. KEY MESSAGE 2...Drier with a return to seasonable temperatures this week. Rain chances return Thursday/Friday. A post-frontal air mass ushers in drier conditions and warmer temperatures on westerly winds this week. As skies gradually clear from the dreary weekend, dewpoints will begin to drop slightly... into the upper 50s as opposed to the low to mid 60s we've been seeing. High pressure begins to slowly build Tuesday into Wednesday, prolonging the clear skies, drier weather, and warmer temperatures through the middle of the week. Expecting temperatures to return to seasonable, in the upper 70s to low 80s, and feel less humid thanks to the lower dewpoints through the end of the week. Chances for rain showers return Thursday and Friday as a low pressure system develops over the Great Lakes and meanders east through southern Ontario. Some uncertainty remains regarding the onset of the showers as there's little consistency in the global ensembles on the actual placement of the low as it tracks through Canada; however, confidence has ticked up slightly in a later show of showers Thursday evening into the overnight period compared to yesterday's model runs. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 06z TAF Update... Through 12z...Moderate confidence in trends but lower confidence in specific timing. VFR/MVFR conditions, however light winds with higher dewpoints and remaining wet ground will remain conducive to the development of areas of fog. Some have already developed across NE MA, parts of RI and SE MA, and up in the Worcester hills. Areas all prone to fog will likely see it before daybreak if they aren't already, and it may become locally dense. Monday and Monday night...High confidence. Any leftover ground fog quickly burns off after sunrise this morning. VFR with SW winds of 7-13 kt with a few gusts up to 20 kts possible in the afternoon/evening hours across the region, though ACK may remain under an inversion that prevents the development of gusts based on the latest forecast soundings. VFR conditions continue tonight outside of any localized patches of ground fog that develop in typically prone locations. Winds become calm/light SW overnight. Tuesday...High confidence. Generally VFR, though lower end VFR to higher end MVFR possible over the interior. W winds 6-13 kt with gusts near the Cape and Islands nearing 20 kt possible. KBOS Terminal...Moderate confidence in TAF. Low clouds remain possible through 12z this morning. KBDL Terminal...Moderate confidence in trends but lower confidence in specific timing. Fog has not developed yet within the valley, though could expect it to do so over the next few hours and reach BDL before sunrise. Outlook /Tuesday through Friday/... Tuesday: VFR. Breezy. Tuesday Night through Wednesday Night: VFR. Thursday: VFR. Breezy. Chance SHRA, slight chance TSRA. Thursday Night through Friday: VFR. Chance SHRA, slight chance TSRA. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Tonight through Monday night...High confidence. The pressure gradient will generally remain weak enough to keep winds/seas below small craft advisory through Monday night. However...nearshore SW winds may gust into the lower 20 knots late Monday result in some decent chop for recreational boaters. Outlook /Tuesday through Friday/... Tuesday: Winds less than 25 kt. Seas locally approaching 5 ft. Tuesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Wednesday: Winds less than 25 kt. Seas locally approaching 5 ft. Wednesday Night through Thursday: Winds less than 25 kt. Thursday Night through Friday: Winds less than 25 kt. Chance of rain showers. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...High Risk for Rip Currents from 8 AM EDT this morning through this afternoon for MAZ024. RI...None. MARINE...None. && $$ DISCUSSION...Frank/McMinn AVIATION...Hrencecin MARINE...Frank/McMinn