


Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
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-- Discussion containing changed information from previous version are highlighted. --571 FXUS61 KGYX 290113 AAA AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 913 PM EDT Sat Jun 28 2025 .SYNOPSIS... Low pressure crosses the area tonight with thunderstorms possible through the evening. High pressure builds in Sunday and Monday for mostly dry conditions and a warming trend. Low pressure tracking through Quebec will drag a cold front across the area Tuesday bringing chances for thunderstorms, a few of which may be on the stronger side. Outside of some mountain showers, the middle to second half of next week looks mostly dry and seasonably warm. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...-- Changed Discussion --Update...Adjusted PoP to account for break in showers. As cold front pushes into the local area chances for showers and isolated thunderstorms will increase from west to east. Otherwise no significant changes. Previous discussion...A warm front is lifting towards the area this afternoon with an area showers and embedded thunder pushing northeast through central Maine. Cloud cover is starting to thin across western New England with areas of convection developing along a cold front across Upstate NY and central PA. Low clouds and patchy fog will likely persist across much of Maine through sunset while some surface heating near the CT Valley and SW NH will allow MU CAPE to rise to around 1000 J/kg. CAMs generally agree that the convection to the west of New England will weaken as it approaches the CT Valley between 00Z and 02Z this evening when instability will be waning. Isolated to scattered thunderstorms remain in forecast through this evening and a strong storm or two cannot be ruled out across western NH. Chances for showers and thunder will diminish after 02Z tonight with areas of fog likely along the coastal plain and within interior valleys. Some fog may become dense near the coast before winds shift out of the NW towards daybreak. Lows tonight will range from the mid 50s north to mid 60s south.-- End Changed Discussion --&& .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... A cold front will be pushing offshore Sunday morning with high pressure building in through Sunday night. Sunday will be a nice day with a mix of clouds and sun and highs ranging from the 70s north to 80s south. High pressure cresting over the area Sunday night will likely lead to fog developing within area valleys. Otherwise quiet weather is expected with lows ranging from the mid 50s to low 60s. && .LONG TERM /MONDAY THROUGH SATURDAY/... Pattern Overview: Our weather pattern looks to remain on the unsettled side as we end up in broad troughing for much of next week at the 500 mb level with a series of surface fronts as well. Global models are hinting at a sharper trough toward the July 4th holiday, but also a bit of a drier airmass that could limit shower activity. Impacts and Key Messages: * Tuesday is a day to watch as warm moist conditions ahead of a cold frontal passage may lead to the development of some stronger thunderstorms and heavy rain. Details: Monday: Monday looks to be warm and dry as a 500 mb ridge builds over the northeast. 850 mb temperatures will build to +16-18C under this ridge which, with clear skies and good mixing, would support surface temperatures in the mid to upper 80s across most of the area, and near 90 in southern New Hampshire. Northwesterly flow should keep dewpoints in the comfortable range making for a pleasant summer day rather than the oppressive heat we saw earlier this week. Skies look to remain clear for a good portion of the night, but 850 mb temperatures continue to build so temperatures Monday night likely only fall into the 60s before leveling off as clouds thicken toward sunrise. Tuesday and Wednesday: As the ridge shifts off to the east, flow becomes southwesterly which looks to drive dewpoints up in to the upper 60s to near 70. This would have some locations feeling sticky with actual temperatures in the mid to upper 80s south of the mountains, feeling more like low to mid 90s. Southeastern New Hampshire may even approach Heat Advisory criteria if trends hold. Other than a little bit more of an uncomfortable day, this heat and humidity may provide forcing for some stronger thunderstorms later on Tuesday as a cold front approaches the area. The latest Long Range Ensemble Forecast has stayed pretty consistent with 1500-2000 J/kg of MUCAPE and 30-35 kts of deep layer shear, suggesting some organized convection as forcing for ascent increases ahead of the front. Current PWATs are modeled to be around 2", so these storms may contain heavy rain at the very least. Any finer details will have to be resolved by CAM guidance later down the road, but this certainly remains a period to watch. Skies clear behind the front, but 850 mb temperatures remain warm so Tuesday night looks like another night in the 60s for low temperatures. Wednesday looks like a drier day for the majority of the area with a more westerly flow maybe supporting showers in the mountains, similarly another front looks to approach in the afternoon bringing about a chance for a rumble of thunder as well. Thursday-Saturday: Models are in surprisingly good agreement that a sharper trough looks to approach the region late week. Where they differ is time of departure, with the GFS being the quickest and the Euro and Canadian keeping in under the influence of the trough through Saturday. Another thing of note is that the airmass around this time looks fairly dry so don`t assume your holiday weekend is going to be a wash. There is still a lot of time for things to change, but my forecast remains on the optimistic side (and close to NBM consensus) with just isolated to scattered showers at this time. && .AVIATION /01Z SUNDAY THROUGH THURSDAY/... Short Term...Low cigs and reduced visibility in showers and fog will bring IFR/LIFR conditions across much of the area tonight. A cold front will bring chances for TSRA near the CT Valley around 00Z with the threat for thunder diminishing after 02Z. Conditions likely improve to VFR Sunday morning. Valley fog will likely bring restriction to KLEB and KHIE Sunday night and possibly to KCON and KMHT. Long Term...VFR prevails most days through Thursday, with the exception being on Tuesday when a cold front brings with it a chance for thunderstorms and heavy rain, and therefore brief restrictions. Some fog development is possible Monday night as moisture increases, and again Tuesday night at terminals that see rain. && .MARINE... Short Term...Winds and seas will remain below SCA thresholds tonight through Sunday night. A warm front lifting into the waters will maintain areas of fog that could become dense tonight. Long Term...SCA conditions are not expected Monday as high pressure slides over the waters. A cold front looks to cross the waters Tuesday night, which may bring about brief SCA conditions and chance for thunderstorms in the afternoon and evening. Sub SCA criteria then returns through Thursday. Flow will remain generally southwesterly. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Legro SHORT TERM...Schroeter LONG TERM...Baron