000 FXUS61 KBOX 071924 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 324 PM EDT Sun Aug 7 2022 .SYNOPSIS... Heat and humidity will continue to be the main weather story well into next week. Heat Advisories continue through Monday, and the threat of isolated to scattered thunderstorms will remain as well. It may be Wednesday before this heat and oppressive humidity finally break in a significant way. Will have daily shots for showers and thunderstorms for much of next week, with more widespread rain expected sometime Wednesday into Thursday. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Forecast is on track this afternoon, with cumulus bubbling across southern New England but only sparse showers so far which continue to pulse up and quickly collapse. As we go through the afternoon the coverage of showers and storms may increase, mainly along and north of the MA pike. Mesoanalysis shows 2000-2500 J/kg of CAPE but with no shear and lackluster mid level lapse rates which should keep any thunderstorms of the garden-variety. With sunset and loss of diurnal heating storms will rapidly diminish in coverage leaving mostly clear skies, save for the south coast where low level moisture will once again bring the threat of low stratus to the Cape and islands. Low temps will be quite warm owing to the very moist airmass, in the mid 70s. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... Monday we rinse and repeat, as has been the story for days now. The hot and humid airmass remains overhead with little change to speak of. SW winds continue and advect in marginally warmer air in the low levels (850 mb temps increase from 18C to 19-20C) so temperatures will be a few degrees warmer, especially in the Connecticut Valley. Highs in the low to mid 90s and dewpoints in the mid 70s mean another day of heat indices at or above 100F. Instability will once again be high (CAPE >1500 J/kg) with poor shear (though a bit higher than Sunday). Not expecting a severe threat with any storms that pop up on Monday afternoon and evening. Any convection that does fire will die down after sunset leaving a dry forecast for the overnight hours. Increasing winds late in the day and overnight will take the edge off, especially along the south coast and offshore. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Highlights... * Slow southward movement to cold frontal boundary will favor increased clouds and a few opportunities for showers and t-storms Tue thru Thurs, with better chances on Wed. * Very warm and humid weather continues on Tues but odds for more cloud cover could temper oppressive heat. Mostly cloudy conditions Wed and Thurs will bring cooler air temps but still quite humid. * Much drier/more refreshing air mass Fri into next weekend with prevailing dry weather. Details: Precipitation Chances: The focus in the first couple of days of the long-term forecast period is a southward-sagging frontal boundary; per ensemble means, this feature projects to bring a few opportunities for showers and thunderstorms late Tue into Thurs. While it remains a heavily convective pattern, which means not everyone will see rains like some of the coarser-resolution global and ensemble guidance QPF would indicate, the front-parallel mid-level flow could favor several rounds of showers or storms, some which could feature local downpours given ensemble mean 2 sigma PWAT levels around 2". Have indicated at least Chance PoP beginning later Tue through Thurs. However a period of Likely was introduced for Wednesday based on reasonable consensus in the EPS/GEFS/GEPS ensemble means with notable 50-70% probs for 24 hour rainfall in the 0.5" or greater range. There remains spread in timing the front's southward progress in the Tue thru Thurs timeframe which still carries some degree of uncertainty, but seems that the middle portion of the workweek should tend to feature more cloud cover and increased chances for welcomed rains. Despite some indications in CIPS Analog guidance, prospects for severe weather in the Tue thru Thurs timeframe appear minimal given weak wind fields and correspondingly low shear values. By late week into the weekend, guidance favors a return to drier weather with continental NW flow and high pressure building into interior and western New England. Temperatures and Humidity Levels: Monday night could be one of the warmer and more humid nights experienced in this stretch of oppressive heat and humidity with widespread lows in the mid to even upper 70s south of the Mass Pike; some indication for cooler lows mid-upper 60s in NE MA as a pressure wedge tries to build down the NH/ME seacoast. Tues looks to be the last very warm day in this stretch of heat and humidity; given cloud cover trends there's still uncertainty on highs here but undercut the warm-biased NBM values by 2-4 degrees. With dewpoints upper 60s to lower-mid 70s, heat indices fall shy of Advisory levels in the mid-80s to low 90s. Wed and Thurs begin a trend toward cooler/more seasonable temperatures but this is due to increasing cloud cover versus any appreciable change in air mass, and humidity levels will however still be elevated. It won't be until the front clears our area for later in the week when a much more refreshing air mass then filters into Southern New England, with surface ridge and broad longwave troughing develops. Continued seasonable with comfortable humidity levels into the weekend. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. 18z TAF Update; This afternoon...High confidence. VFR. Iso to widely sct SHRA/TSRA through 02Z, mainly along/north of I-90. SW winds around 10 kt, gusts 18 to 22 kt. Tonight...Moderate Confidence. Mainly VFR. Areas of IFR in stratus expected towards the south coast late. Light SW winds. Monday...Moderate Confidence. Mainly VFR. IFR stratus more likely to persist towards the south coast around daybreak. Brief periods of MVFR in any afternoon showers or thunderstorms. SW winds 5-10 kt with gusts up to 20 kt. Monday night...High confidence. VFR. SW winds 5-15 kts gusting to 25 kts for southeast MA. KBOS...Moderate confidence in TAF due to uncertainty as to whether any TSRA makes it to the terminal this afternoon. Greatest risk, though still low, is no sooner than 20z. KBDL...Moderate confidence in TAF due to uncertainty as to whether any TSRA makes it to the terminal this afternoon. Greatest risk, though still low, is no sooner than 19z. Outlook /Tuesday through Thursday/... Monday Night: VFR. Breezy. Slight chance SHRA, slight chance TSRA. Tuesday: VFR. Breezy. Chance SHRA, isolated TSRA. Tuesday Night: Mainly VFR, with areas IFR possible. Chance SHRA. Wednesday: MVFR/IFR conditions possible. Chance SHRA. Wednesday Night: Mainly VFR, with local IFR possible. SHRA likely. Thursday: Mainly VFR, with local MVFR possible. Chance SHRA, isolated TSRA. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Through Monday night...High Confidence. This afternoon and tonight, SW winds 15-20 kt with gusts up to 25 kt. Seas increase to 5-6 ft on the southern waters tonight. Winds and seas diminish some into Monday, with rough seas lingering across the outer coastal waters the longest. Winds and seas increase once again Monday evening and overnight. Outlook /Tuesday through Thursday/... Monday Night: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Slight chance of rain showers, slight chance of thunderstorms. Tuesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Chance of rain showers. Tuesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers. Wednesday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers. Wednesday Night: Winds less than 25 kt. Rain showers likely, isolated thunderstorms. Thursday: Winds less than 25 kt. Chance of rain showers, isolated thunderstorms. && .CLIMATE... Record Maximum Temperatures August 7th: BOS 98F  ORH 98F  PVD 95F  BDL 100F  August 8th: BOS 96F  ORH 94F  PVD 95F  BDL 98F  && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Heat Advisory until 8 PM EDT Monday for CTZ002>004. MA...Heat Advisory until 8 PM EDT Monday for MAZ002>023-026. RI...Heat Advisory until 8 PM EDT Monday for RIZ001>007. MARINE...Small Craft Advisory until 8 AM EDT Tuesday for ANZ231>235-237. Small Craft Advisory until 1 AM EDT Monday for ANZ236-250. Small Craft Advisory until 8 PM EDT Tuesday for ANZ254>256. && $$ SYNOPSIS...BW NEAR TERM...BW SHORT TERM...BW LONG TERM...Loconto AVIATION...Loconto/BW MARINE...Loconto/BW CLIMATE...