


Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
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211 FXUS61 KGYX 061820 AFDGYX Area Forecast Discussion National Weather Service Gray ME 220 PM EDT Sun Jul 6 2025 .SYNOPSIS... Heat and humidity persist into Monday with shower and thunderstorm chances mainly confined to the mountains. A cold front gradually moves through northern New England Monday night and Tuesday with showers and storms. The front then stalls near New England for much of the week, keeping the chance for showers and storms each day. High pressure then builds in from the north next weekend. && .NEAR TERM /THROUGH TONIGHT/... Isolated to scattered showers will continue to develop across the mountains and foothills this afternoon. Showers across NY/VT should move into northern NH over the next few hours. With building instability, would expect thunder to accompany these as the afternoon progresses. Lesser coverage is forecast into the interior and perhaps the coast later this afternoon. With ample flow aloft, stronger cells will be capable of gusty winds in addition to brief downpours and lightning. Rain chances retreat north with the loss of daytime heating this evening and overnight. Have kept mention of showers/thunder in along the CAN/US border. Otherwise, tonight will be mild with lows only falling to the lower 70s and upper 60s. Would expect some valley fog to develop after midnight, but quickly dissipate come Monday morning. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... Stalled frontal boundary remains NW of the forecast area Monday with warm air still entrenched. Hot and humid condition are forecast to continue, and have left the Heat Advisory unchanged. However, there will be additional cloud cover for the day that could slow temp rises through the morning and temper MaxTs. Heat index values will still (un)comfortably make it into the mid 90s after a mild night. Shower and thunderstorm coverage has decreased through early afternoon, but expect PoPs to increase come mid to late afternoon. The stagnant front will begin to push east and moisture will be arriving from the south from tropical remnants. With afternoon instability, can`t rule out a rumble of thunder across southern NH before the evening progresses and this lift is lost. Went below NBM PoPs for Monday night across southern NH and far southern ME. There will be a window before deeper moisture moves into this region, either through the incoming front or tropical remnants. Expect this to encompass much of Monday night, before chances again increase Tues AM. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Overview... A slow moving front presses through the forecast area on Tuesday, and remains stalled south of New England through the end of the week. A weak wave of low pressure rides along the front Friday and Saturday, with High pressure then building southward on Sunday. Details... The slow moving frontal boundary is expected to make gradual southward progress during the day on Tuesday, like starting from the mountains and foothills in the morning. Remnant showers and an isolated thunderstorm from the previous day`s convection are likely to accompany the front during the morning, with more convection developing along the front by the late morning and early afternoon as the front sags south. Temperatures warm into the 80s ahead of the front during the day, with upper 80s likely across southern NH, and 70s north of the front. Some moisture from the remnants of Chantal likely becomes entrained in the front on Tuesday, especially across southern and coastal areas. Combined with the warmer temperatures, some stronger storms with gusty winds and heavy downpours will be possible Tuesday afternoon across southern areas. By Wednesday and Thursday, the front is expected to stall south of New England. Behind the front, relatively cooler and drier conditions follow, but the airmass remains moist enough for scattered afternoon convection each day, especially across the higher terrain. Mainly 70s to low 80s are likely on Wednesday, with some mid 80s possible through the Connecticut River Valley. Temps cool further on Thursday, with mainly 70s expected. Showers likely also become more widespread on Thursday as a weak wave of low pressure moves along the front to the south. A steadier period of rain is possible Thursday night and Friday as the low makes it`s closest pass, but there is still a question as to how far north this area of rain will progress. For now, scattered showers look most likely, but we`ll continue to monitor how organized this system can become over the next few days. By next weekend, the system likely moves away with high pressure returning at the surface. A trailing upper level low behind the system keeps the chance for diurnal showers and storms each day. At a glance the forecast would look quite dreary for much of the week, but most of the time conditions will be dry. Daily showers and storms are likely, especially across the higher terrain, but would be mostly brief and progressive. We will have to monitor areas that see repeated rounds of convection through the week for any flood risk concerns, but that looks to be a localized threat evolving with time. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Short Term...VFR this afternoon and evening. Brief SHRA or TS could bring tempo MVFR vis in downpours. These may also bring locally gusty winds. Showers dissipate this evening, with some valley fog developing after midnight. MVFR to IFR conditions develop along the coast and US/CAN border as well as southern NH Monday night. Long Term...VFR conditions prevail during the daytime most of the week, but brief restrictions with afternoon and evening showers and thunderstorms will be possible each day at all terminals, through more likely at interior terminals. Nighttime valley fog will also be possible each night. && .MARINE... Short Term...SCA continues through midnight tonight. There will be a lull Monday morning before conditions may again approach SCA Monday evening and overnight. Surface temperature inversion may well minimize gusts, keeping these below SCA. This could also lessen wave height potential. As a result, chose not to extend the SCA at this time. Stalled front along the US/CAN border will near the waters Tuesday morning. Long Term...A cold front crosses the waters on Tuesday, and then stalls south of the waters through the remainder of the week. A weak low pressure center likely moves along this front late in the week and into next weekend. Conditions look to remain below SCA level from Tuesday through at least the end of the week. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Heat Advisory until 8 PM EDT Monday for MEZ012-018>020-023-024- 033. Beach Hazards Statement until 8 PM EDT this evening for MEZ027- 028. NH...Heat Advisory until 8 PM EDT Monday for NHZ006>015. MARINE...Small Craft Advisory until 6 AM EDT Monday for ANZ150-152-154. && $$ NEAR TERM...Cornwell SHORT TERM...Cornwell LONG TERM...Clair