Area Forecast Discussion
Issued by NWS Portland, ME

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626 FXUS61 KGYX 070606 AFDGYX Area Forecast Discussion National Weather Service Gray ME 206 AM EDT Mon Jul 7 2025 .SYNOPSIS... Another hot and humid day today with high temperatures in the 90s but feeling closer to 100 degree in many areas. A few showers and thunderstorms will be possible, but they do not look like they will be widespread enough to provide much relief. So that means another muggy night tonight before one more very warm day across the southern parts of the area Tuesday. The front unfortunately will not make much progress south and will stall over southern New England. This will keep our area cooler but continue with threats for afternoon showers through the week. && .NEAR TERM /TODAY/...
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Warm front remains draped across ME...but is largely confined to the CAR forecast area. Clouds and showers will continue to skirt thru northern Franklin Co and thru central Somerset Co...but otherwise a dry and mostly clear night is expected locally. Some rain showers did occur in the Lakes Region east thru the ME Capital Region...so if valley fog occurs overnight these will be the most likely areas. This afternoon will again feature twin hazards. First and most widespread will be the heat. Since the front made little progress...today will be much like yesterday. Widespread low to mid 90s are expected along with high dewpoints. The resulting heat index values will be mid to upper 90s. The current advisory looks good. The second but more conditional threat will be thunderstorms again. ECMWF EFI has a significant number of members with favorable CAPE/shear overlap during the afternoon...especially near the warm frontal boundary. This will mainly be across western ME. SPC HREF also has some low probablilites of rotating updrafts across parts of western NH and into most of the northern half of the forecast area. A little more in the way of shear will introduce a small hail threat despite the very warm environment. But otherwise the main hazard will be gusty to damaging winds. This is supported by an SPC Marginal Risk as well as by CSU machine learning guidance. It would not surprise me to see a few severe storms...but likewise it could struggle like yesterday without a more significant forcing mechanism.
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&& .SHORT TERM /TONIGHT THROUGH TUESDAY/...
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Front will continue to sag south overnight. With the loss of daytime heating I do not anticipate much in the way of precip overnight...but with the boundary nearby and WAA still continuing along and south of it an isolated to widely scattered shower is possible. I will keep those slight chance to chance PoP going thru the overnight. Without a strong frontal push thru the area it should be another warm night. The NBM has lows near 70 for many areas...and based on ECMWF EFI showing a strong preference for warm temps I think this makes sense. Tue will be the last of the very warm days for the forecast. South of the front will remain quite warm and muggy. Highs may be able to top out around 90 across southern NH...with a very sticky 80s elsewhere. The precip forecast will be interesting as the front will be lingering near the coast. If it has not cleared the coast by afternoon...convection is likely to pop right along the shore. The shear is forecast to be weaker by Tue...so the hazards will be more torrential rain and lightning than severe.
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&& .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Key Message: Cooler and generally showery thru the extended. Impacts: No significant weather impacts anticipated. Forecast Details: Overall I did not adjust the NBM much thru the extended. The only change was to tweak thunder chances beyond Tue. There tends to be a high bias in thunder in the extended...by about a category. So beyond day 4 I capped things at isolated thunder. Otherwise the front will stall south of the forecast area while high pressure builds across to our north. The location of the high will promote northeast to east winds and a largely onshore flow pattern. This will keep temps on the cooler side for July...and at least puts the threat for significant heat behind us for a little. Precip looks to be driven mostly by diurnal processes. There will not be much large scale forcing for ascent...so daytime heating will allow for scattered convection. Towards the end of the period a more significant trof will approach and may lead to more widespread precip locally. Any concern for flooding will revolve around where rain falls each day. If we end up in a situation where repeated rounds of convection occur in the same locations that would elevate the flood risk. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... Short Term...VFR conditions expected today. There may be some valley fog south of the cloud deck where precip occurred today. This would mainly be the NH Lakes Region and around the lower Kennebec River Valley...which may include AUG. I have a brief period of IFR conditions there near sunrise. During the afternoon SHRA/TSRA will develop again...local MVFR conditions would be possible. However at this time the TAF sites do not appear particularly likely to see convection. The greatest chance for an afternoon SHRA/TSRA will be at HIE. Long Term...VFR conditions expected to prevail much of the extended. Local MVFR or lower conditions will be possible...especially during the afternoons...in any SHRA/TSRA that form. Confidence is quite low in location for highest chance of precip however. As surface high pressure tries to nose in...valley fog may develop during the nights...and will be most likely for areas that do receive rain. && .MARINE... Short Term...Marginal SCA conditions may diminish this morning...but southwest winds are expected to freshen again ahead of a slow moving front during the afternoon. I have extended the SCA thru the evening. Again this will be mainly for gusts right around 25 kt and seas building to near 5 ft. The front will finally reach the coastal waters by Tue...with showers and thunderstorms possible along it during the afternoon. Long Term...The front will hang up over southern New England into the entrance to the Gulf of ME. This will keep showers and storms in the forecast for much of the week. Winds and seas are generally expected to remain below SCA thresholds. && .GYX WATCHES/WARNINGS/ADVISORIES...
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ME...Heat Advisory until 8 PM EDT this evening for MEZ012-018>020- 023-024-033. NH...Heat Advisory until 8 PM EDT this evening for NHZ006>015. MARINE...Small Craft Advisory until 11 PM EDT this evening for ANZ150- 152-154.
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&& $$ SYNOPSIS... NEAR TERM...Baron/Legro SHORT TERM...Legro LONG TERM...Legro AVIATION...Legro MARINE...Legro