000 FXUS61 KBOX 071118 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 718 AM EDT Sun Aug 7 2022 .SYNOPSIS... Heat and humidity will be the main weather story right into early next week. Heat Advisories have been extended through Monday, and the threat of isolated to scattered thunderstorms will remain as well. It may be Tuesday, or later, before this heat and oppressive humidity finally breaks in a significant way. Will have daily shots for showers and thunderstorms for much of next week, but no washouts are anticipated at this time. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 715 AM Update: No significant change needed to the forecast or key messages for today, with oppressive heat and humidity again a focus, with afternoon isolated to widely scattered showers or thunderstorms dissipating by sundown. Remains very muggy this morning with dewpoints generally in the low to middle 70s again. Other than stratus affecting Cape Cod and the Islands, mostly clear to partial cloudiness begins Sunday. Strong heating to push highs into the low-middle 90s, with upper 80s across the Cape and Islands. Heat Advisories continue with no changes to its status, with expectation of 95 to 103F heat indices. Given the high dewpoints, won't take much heating to develop cumulus fields with moderate instability and weak wind shear environmental setup for today. On the mesoscale, looks like a subtle windshift boundary sets up and could force weak convergence along or just north of the Mass Pike per HRRR and NAM-3km guidance. May see more in the way of shower/t-storm coverage compared to yesterday toward widely scattered near or north of the Mass Pike. HRRR has been really consistent in showing storms developing near the berkshires by mid-aftn (19z-ish) and moving eastward through late-afternoon into central MA and on into Metrowest. Poor wind fields/weak shear to make any showers or storms highly pulse in character, with lightning and localized brief downpours the main risk versus any severe risk. Previous discussion: Still no significant changes to the overall pattern today. heat and humidity continue, along with the risk for some disorganized showers and thunderstorms later today. The only synoptic feature that would provide more focus to this convection, a stalled front, will remain well to our north today. Much like the past few days, not everyone will see a shower or thunderstorm, but do not have enough confidence to pin it very precisely. Locations farther inland and closer to northern New England will have a greater risk than those farther south and east. Expecting a little more of pressure gradient today, so no east coast seabreezes. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... Any lingering showers and thunderstorms should diminish quickly with sunset. Leading to another mostly rain-free night. It will remain muggy, with yet another round of stratus and patchy fog towards southeast MA. No real change in air mass Monday, so no real change to the forecast either. Continued heat and humidity with a risk for afternoon showers and thunderstorms. Heat Advisories continue as posted through Monday. && .LONG TERM /MONDAY NIGHT 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 /12Z SUNDAY THROUGH THURSDAY/... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. 12z TAF Update; Today: Generally VFR. MVFR-IFR stratus/mist from overnight near the southern coast to dissipate by 15z. Iso to widely sct SHRA/TSRA by mid afternoon to sundown, mainly along/north of I-90. Included VCSH at ORH but too low prob to carry mention at either BDL, BED and BOS. SW winds around 10 kt, gusts 18 to 22 kt. Today...Moderate Confidence. Mainly VFR. IFR stratus more likely to persist towards the south coast this morning. Brief periods of MVFR in any showers or thunderstorms. SW winds 10-15 kt with gusts up to 25 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. 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 /Monday Night through Thursday/... Monday Night: Mainly VFR, with local MVFR possible. Breezy. Slight chance SHRA. Tuesday: VFR. Breezy. Chance SHRA, slight chance TSRA. Tuesday Night: Mainly VFR, with local IFR possible. Chance SHRA, slight chance TSRA. Wednesday: MVFR/IFR conditions possible. Chance SHRA, slight chance TSRA. Wednesday Night: MVFR/IFR conditions possible. SHRA likely, chance TSRA. Thursday: Mainly VFR, with local IFR possible. Chance SHRA. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Through Monday...High Confidence. Light winds and seas with early morning areas of fog with reduced visibility. Today 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. Outlook /Monday Night through Thursday/... Monday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Slight chance of rain showers. Tuesday: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain showers, slight chance of thunderstorms. Tuesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers, slight chance of thunderstorms. Wednesday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers, slight chance of thunderstorms. Wednesday Night through Thursday: Winds less than 25 kt. Rain showers likely, chance of 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 from noon today to 6 AM EDT Monday for ANZ231>235-237. Small Craft Advisory from noon today to 1 AM EDT Monday for ANZ236-250. Small Craft Advisory from noon today to 2 PM EDT Monday for ANZ254>256. && $$ SYNOPSIS...Belk/Loconto NEAR TERM...Belk/Loconto SHORT TERM...Belk LONG TERM...Loconto AVIATION...Belk/Loconto MARINE...Belk/Loconto CLIMATE...