


Area Forecast Discussion
Issued by NWS Boston, MA
Issued by NWS Boston, MA
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155 FXUS61 KBOX 150126 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 926 PM EDT Mon Jul 14 2025 .SYNOPSIS... Showers will diminish tonight. Heat and humidity will build once again Tuesday through at least Thursday, along with chances of showers or thunderstorms each afternoon and evening. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Key Messages: * Flood Watch canceled. * Warm and muggy night ahead tonight. Showers and thunderstorms in western New England were weakening with loss of daytime heating, but will persist for a little longer as they feed off lingering instability located along PWAT axis. As a result we have canceled the Flood Watch. Otherwise, a warm and muggy night is in store with light S/SW flow, which will also promote areas of low clouds and fog. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... Key Messages: * Heat Advisory goes into effect for most of the region Tue. Building ridge of high pressure brings the return of hot and humid conditions Tuesday. Guidance has 925 temperatures increasing from 19C today to 24C tomorrow afternoon. At the surface, this translates to high temperatures climbing into the upper 80s and low 90s for most areas Tuesday afternoon. While these temperatures are far from unheard of, dewpoint values will climb into the lower to mid 70`s resulting in heat index values around 95 above. The greatest likelihood of this will be for inland areas away from the Cape and Islands. Low temperatures will remain quite mild and dewpoints high. Elevated low temperatures spell trouble for those without access to proper sources of cooling and relief from the day`s high temperatures. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Key Messages: * Hot and humid during the middle of this week, with elevated heat indices around 95-100F. Heat Advisories for Tuesday into Thursday for most of southern New England. Heat Advisory may be needed for Friday too. * Becoming more unsettled late Thursday-Friday with increasing chances for showers and thunderstorms. Most of this portion of the forecast will see southern New England om the warm and very humid side of a cold front. This front will take its time to move from the Great Lakes and Saint Lawrence River valley until it finally attempts to cross our region Friday night. The holdup is a large high pressure off the southeast USA coast. The position of this high pressure will keep pushing heat and humidity our way. Heat Advisories already posted for most of southern New England for the middle part of this week. It may need to be extended into Friday as well. Slightly cooler conditions anticipated once this front passes by this weekend into early next week, but that should mean right around average temperatures for this time of July. The heat and humidity should mean at least a low risk for mainly afternoon and evening thunderstorms. There remains a better signal for more organized forcing later Thursday and a weak trough shifts in from the west. This will bring higher chances for more widespread showers/storms. Weak winds aloft will support slower storm motions and given the high amounts of moisture signal a threat for flash flooding. We`ll have to keep eyes on that as we go through this week. Friday is a more complicated forecast dependent upon the timing of the aforementioned front. Looking ahead to this weekend, this front doesn`t get too far south of our region, and could return as a warm front sometime Sunday into Monday. That could trigger another round of showers and possible thunderstorms. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 00z Update: After remaining showers and thunderstorms dissipate, winds turn SSW brining in yet another round of low stratus and fog. Highest confidence near the south coast and CT river valley. Less certain in and around Boston. Tuesday: Moderate Confidence VFR outside the Cape and Islands where IFR stratus may hang on much of the day. Low chance for a weak shower or thunderstorm. KBOS Terminal...High confidence in TAF. KBDL Terminal...High confidence in TAF. Outlook /Wednesday through Saturday/... Wednesday through Wednesday Night: VFR. Slight chance SHRA, slight chance TSRA. Thursday: Mainly VFR, with local MVFR possible. Breezy. Chance SHRA, slight chance TSRA. Thursday Night: VFR. Breezy. Slight chance SHRA. Friday: VFR. Chance SHRA, chance TSRA. Friday Night: VFR. Slight chance SHRA, slight chance TSRA. Saturday: Saturday Night: Slight chance SHRA. Sunday: Chance SHRA, chance TSRA. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Tonight through Tuesday...High confidence. Weak pressure gradient will keep winds/seas below Small Craft Advisory thresholds through Sunday: seas 2-3 ft with E winds over the southern waters and SE winds over the eastern waters up to 15 kts during the afternoon hours, remaining light in the overnight hours. Main concern for mariners will be areas of fog tonight that may redevelop again tonight. Inland Thunderstorms are unlikely to affect the waters this evening. Winds turn more SW on Tuesday between 10-15 knots. Outlook /Wednesday through Saturday/... Wednesday: Winds less than 25 kt. Wednesday Night: Winds less than 25 kt. Slight chance of rain showers, slight chance of thunderstorms. Thursday: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers, slight chance of thunderstorms. Thursday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers. Friday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers, slight chance of thunderstorms. Friday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers, slight chance of thunderstorms. Saturday through Saturday Night: Winds less than 25 kt. Sunday: Winds less than 25 kt. Slight chance of rain showers. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Heat Advisory from 11 AM Tuesday to 7 PM EDT Thursday for CTZ002>004. MA...Heat Advisory from 11 AM Tuesday to 7 PM EDT Thursday for MAZ003>007-010>021-026. RI...Heat Advisory from 11 AM Tuesday to 7 PM EDT Thursday for RIZ001>007. MARINE...None. && $$ SYNOPSIS...FT NEAR TERM...JWD SHORT TERM...FT LONG TERM...Belk AVIATION...FT MARINE...FT