


Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
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125 FXUS61 KGYX 182252 AFDGYX Area Forecast Discussion National Weather Service Gray ME 652 PM EDT Fri Jul 18 2025 .SYNOPSIS... Post frontal breezy westerly wind gusts will weaken this evening. Seasonable and dry weather continues Saturday, but chances for rain and thunderstorms will increase on Sunday. Storms may contain brief downpours. Early next week we return to fair and seasonable weather. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 650 PM Update...Little change to the going forecast for the evening and overnight. Winds will diminish and skies will remain clear. Previously... Impacts and Key Messages: * No significant weather impacts expected High pressure continues to build in this afternoon which will help to loosen the pressure gradient and keep gusts weakening through the evening, and eventually go calm. This along with clear skies looks like a favorable setup for radiational cooling, dropping temperatures into the mid to upper 40s north of the mountains, mid to low 50s in the foothills and valleys, and mid to upper 50s on the coastal plain. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Impacts and Key Messages: * No significant weather impacts expected High pressure remains in place Saturday making for another mostly clear day. Canadian wildfire smoke will pass to the north of the region tomorrow with zonal flow keeping it more elevated and out of our area. Some hazy skies may be evident in northern zones and to those recreating in the higher terrain, but it will be subtle enough to not include in the forecast. Temperatures climb into the 80s south of the mountains, and into the mid to upper 70s to the north. Low pressure begins its approach from the Great Lakes Region with broad 500 mb troughing developing as well. This will make for a cloudier night and thusly warmer low temperatures. Locations north of the mountains look to bottom out in the upper 50s with locations to the south more in the low to mid 60s. A more southwesterly flow develops overnight as well which may hold southeastern New Hampshire in the upper 60s for lows as the more moist flow increases dewpoints there. Depending on the timing of the front it is possible a few showers sneak into the area overnight, mainly in the north, but the bulk of the showers and potential thunderstorms look to hold off until after sunrise. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Overview: Broad upper level trough will move unsettled weather through the region into Sunday. After a cold front pushes through, drier conditions take hold of New England through Wednesday. Late week, low pressure passes to the north bringing frontal systems through New England as well as the chance for rain. Potential Forecast Impacts: * Thunderstorm intensity on Sunday hinges on the progression of a cold front swinging through New England. Stronger storms containing gusty winds will be possible where daytime heating can build ahead of the front. Details: By Sunday morning, low pressure will be sliding east toward New England. There remains differences in timing and shape of this feature and associated fronts. Some solutions have a more NE translation of the front, while others bring a more easterly component. Showers remain likely for much of the area, but better timing and coverage will need to come into focus over the next few iterations of data. Continue to see building instability in portions of SE NH and coastal/interior southern ME through the daytime hours. This is ahead of the front, so amount may vary on how quickly the front is passing. Early breakdown of values show potential for a good CAPE/shear balance for mini-supercell development ahead of the front. This is based on resultant BRN numbers around 18-20 from ~2000 j/kg of CAPE and 35 kt of 0-6km shear. Would expect CAPE and other instability parameters (such as lapse rates) to have the greatest fluctuation and influence of severity here. Where storms do develop in this environment all hazards will be possible, but most probable at this time are gusty winds. With the passage of the cold front in the evening, Monday shapes up to be very pleasant (similar to today, Friday). NW winds remain breezy through the day with some upslope clouds keeping mtn daytime highs about 10 degrees cooler than interior areas. Slackening winds and clear skies under high pressure may bring a cool Monday night where lows dip into the mid 40s in the mountains and lower 50s elsewhere. From there, it is a slow warming trend into late week with the next chance of rain Thursday with another passing low and cold front. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... Short Term...VFR will prevail through Saturday. Some lowering of ceilings toward MVFR is expected Saturday night as low pressure approaches the region. Some showers and possibly thunderstorms may near HIE in the early hours of Sunday morning. No low level wind shear is expected at this time. Long Term...MVFR with some areas of IFR on Sunday with SHRA and later in the afternoon TS for at least SE NH terminals. Coastal fog may develop along the ME midcoast for much of Sunday. A cold front passing will improve conditions with wind shifting NW Monday. Gusts to 25 kt will be possible before slackening Monday night. VFR continues into Tues and Wed. && .MARINE... Short Term...Wind gusts and seas remain below SCA criteria through Saturday night as high pressure builds over the region. Winds shift from northwesterly to southerly by Saturday morning. Long Term...Below SCA conditions Sun - Wed. A cold front will approach the waters Sunday evening, passing into Monday morning. Showers/storms may accompany the frontal passage, with a NW wind shift. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Beach Hazards Statement from Saturday morning through Saturday evening for MEZ027-028. NH...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM...Baron/Ekster SHORT TERM...Baron LONG TERM...Cornwell AVIATION... MARINE...