


Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
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010 FXUS61 KGYX 060023 AFDGYX Area Forecast Discussion National Weather Service Gray ME 823 PM EDT Sat Jul 5 2025 .SYNOPSIS... Heat and humidity continue to build this weekend with shower chances mainly confined to the mountains on Sunday. Showers and thunderstorms are possible Monday and Tuesday as a cold front slowly moves through the region. The front then stalls near New England for much of the week, keeping the chance for showers and storms each day. && .NEAR TERM /THROUGH SUNDAY/... 830 PM Update... Increased cloud cover areawide from the previous forecast as satellite imagery shows widespread clouds continuing to stream southeastward over the H5 ridge axis and approaching MCS feature over southern Quebec. Also increased PoPs through the night across the north based on latest radar trends and surface observations/webcams. While the 00Z RAOB report shows dry air in the low-levels, there is more moisture into the mid-levels and therefore showers are likely to develop shortly towards the Canadian Border and mountains. Previously... Fairly thick smoke layer aloft has really took a bite out of insolation today and as a result high temps are falling a little short of the forecast. I cooled things a couple of degrees thru the evening to account for this. Then we have to watch decaying MCS across southern Quebec for chance for showers tonight. Radar shows echoes crossing the St. Lawrence currently...but little in the way of observed rainfall. I have some isolated to widely scattered showers mentioned but I could see it going either way. There is little if any instability to sustain convection across the area...but as the warm front moves in there will be sufficient forcing for ascent and maintain some shower threat. Hi-res guidance has much of it drying up...with what is leftover skirting parts of Somerset Co before exiting the forecast area. && .SHORT TERM /SUNDAY NIGHT/... Main concern Sun will be the heat and humidity. Temps will climb back into the 90s for a good portion of the area with dewpoints surging back into the 60s to near 70. As a result heat index values will be in the mid 90s on the lower end. A few readings near 100 are possible. But even if we end up on the cooler side of the forecast...a holiday weekend with lots of people outdoors will likely lead to greater impacts and I feel a slight expansion of the heat advisory across all of southern NH and coastal Cumberland Co is warranted. Otherwise there were no changes to the headline. There also remains a conditional risk for severe thunderstorms Sun afternoon. The warm front will remain draped across ME and storms are possible along it. The question is whether they actually occur in the forecast area. The threat is rather low for our area...but if storms occur there is enough shear and favorable enough thermodynamic profiles for gusty to damaging winds from the stronger convection. I did not add enhanced wording to the forecast...but will mention the conditional threat in HWO and briefing products. && .LONG TERM /MONDAY THROUGH SATURDAY/... Overview... A frontal boundary sags southward on Monday with a warm and humid airmass in place. Relatively cooler air brings highs back into the 80s for Tuesday and Wednesday, with scattered showers and thunderstorms each day. The pattern then trends toward cooler and more unsettled conditions by late in the week into next weekend. Details... A warm and humid airmass remains in place again for most of the area on Monday as a ridge remains across the Northeast. Heat indices climb into the low to mid 90s across most of the same areas that see the heat on Sunday, with cooler readings across the north. As the front sags southward, a sharp temperatures gradient sets up with highs in the low to mid 70s toward the Canadian border with clouds, showers, and storms. The southward progress of this front through the day remains a variable factor, with any further southward progress bringing cooler and wetter conditions. Overall, there remains more uncertainty with the Monday heat because of the front than the heat on Sunday. Additionally, the storms that develop have the potential to be strong with gusty winds. Tuesday and Wednesday see the continued chance for scattered showers and storms each day as the front lingers across New England with temperatures warming into the upper 70s and 80s each day. By late in the week, a wave of low pressure likely rides along the stalled front, bringing a better chance for more widespread showers and storms late in the week. Additionally, moisture from the remnants of Chantal may become drawn into this system, increasing the rainfall potential. We`ll have to monitor the progress of Chantal`s path and moisture plume through the week. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... Short Term...Mostly VFR conditions expected thru Sun night. Southwest breeze tonight should prevent much valley fog from forming. Otherwise local MVFR or lower conditions are possible but not likely in SHRA/TSRA over western ME mtns Sun afternoon. Long Term...VFR prevails most of the time at all terminals from Monday through Wednesday, but brief restrictions with afternoon showers and thunderstorms will be possible at all terminals. Chances for more restrictions increase late in the week and into next weekend with more showers and storms developing. && .MARINE... Short Term...Southwest winds will increase on Sun. Outside of the bays winds may gust to 25 kt and seas will build to around 5 ft. Given the relatively nice weather and busy holiday weekend I prefer to have a SCA in effect for these conditions. Winds and seas will diminish Sun night. Long Term...High pressure remains centered off the East Coast early this week. A slow moving cold front sags southward Monday and Tuesday, stalling across the waters for much of the week. Conditions look to remain below SCA levels as the front stalls overhead most of the week && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Heat Advisory from 11 AM Sunday to 8 PM EDT Monday for MEZ012- 018>020-023-024-033. Beach Hazards Statement from 8 AM EDT Sunday through Sunday evening for MEZ027-028. NH...Heat Advisory from 11 AM Sunday to 8 PM EDT Monday for NHZ006>015. MARINE...Small Craft Advisory from 2 PM Sunday to 6 AM EDT Monday for ANZ150-152-154. && $$ NEAR TERM...Tubbs SHORT TERM...Legro LONG TERM...Clair