Area Forecast Discussion
Issued by NWS Portland, ME

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008 FXUS61 KGYX 090243 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1043 PM EDT Tue Jul 8 2025 .SYNOPSIS... A weak cold front crosses the area this afternoon and evening providing the forcing for showers and storms. Chances for afternoon showers and storms stay in the forecast through the Thursday. High pressure will bring a dry period Friday into the weekend with increasing temperatures. Shower activity and possible heat returns the beginning of next week. && .NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
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Backdoor cold front continues to march thru NH overnight. East of the front cooler temps but a still moist air mass will support low clouds and some patchy fog. The most dense fog should remain over the waters however. The front has also undercut the instability...with convection expected to remain elevated thru morning. Showers continue to percolate along the gradient between the remaining elevated instability and stable air to the north. The 09.00z GYX sounding showed around 600 J/kg MUCAPE locally...but the OKX sounding was over 3000 J/kg. So as long as we keep southwest winds aloft...some advection of this instability will continue overnight. That should be good enough to warrant PoP remaining in the forecast overnight...but slowly diminishing to chance/slight chance by morning. We also still have PWAT values near 2 inches...so any convection is going to be capable of brief torrential rain. 1 to 2 inches per hour is possible with any shower. If a flood threat were to evolve it would be because the heaviest showers start to train in the same location.
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&& .SHORT TERM /7 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... Cooler conditions settle in behind the front for tomorrow, with most spots topping out in the 70s. Some low to mid 80s are likely reserved for the Connecticut River Valley. Behind the front, pop up showers and mainly cloudy conditions prevail most of the day. Scattered shower coverage increases during the afternoon hours, especially across the higher terrain. Along the coast, more low clouds are likely with an easterly flow. Showers decrease in coverage Wednesday night, but some scattered showers are likely to continue through the overnight hours. Temperatures cool more than the last few night, with lows dipping into the low to mid 60s in most locations. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Impacts and Key Messages: * Summer pattern with periods of showers and thunderstorms * No strong signals for any significant severe or flash flooding thunderstorms at this time. Pattern will consist of a progressive zonal flow with two mid-level shortwave troughs expected to cross north of the region through this forecast period. Thursday into the evening the first organized trough will cross the region sparking scattered showers and thunderstorms to the region. PWAT values could surge to 1.5" across the area, but storm motion should be sufficient to mitigate flash flood concerns. Effective Bulk Shear looks minimal also, so severe threat doesn`t seem anything above marginal as worst case at this time. Front is expect clear the area by Friday morning with some lingering daytime instability showers possible in the mountains, but westerly flow is expected. Ridging is expected for most of the weekend with building heat once again, but looking dry at this point for Saturday. The second shortwave trough will approach the area by late Sunday, with some timing difference is the ensemble guidance. There is a chance for thunderstorms late Sunday, but timing of this feature is plus or minus 18hrs at this point, so will see how things trend. Overall looks like a descent summer weekend, albeit a little warm. Shower activity chances and heat likely to build the beginning the next week as temperatures trend back above normal for the heart of summer. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... Short Term...Scattered showers and storms continue this afternoon and evening. Probs remain low at most terminals, with PWM most likely to see another shower. Ceilings lower tonight with IFR in most locations with some fog also possible. MVFR ceilings prevail on Wednesday, with some showers also possible at times. IFR to MVFR ceilings prevail Tuesday with some fog also possible. Long Term...Fog formation is possible Wednesday night leading to LIFR conditions as rich low level moisture remains in the area. Cloud cover could limit this development threat. Showers and thunderstorms expected on Thursday with clearing for Friday through Saturday with VFR conditions expected. && .MARINE... Short Term...Conditions remain below SCA levels as a cold front slowly moves southward across the waters tonight. Areas of fog are likely to continue into Tuesday. Long Term...Conditions are expected to remain below SCA conditions through this period. Will have to watch for fog development chances Wednesday night with NE onshore flow. Thunderstorms are possible over the coastal water Thursday evening. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Legro SHORT TERM...Clair LONG TERM...Dumont AVIATION...Clair MARINE...Clair