Area Forecast Discussion
Issued by NWS Portland, ME

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484 FXUS61 KGYX 302100 AFDGYX Area Forecast Discussion National Weather Service Gray ME 500 PM EDT Sun Jun 30 2024 .SYNOPSIS... Strong to severe storms will be possible through this evening as a cold front drops south and across the area. Cooler and less stifling humidity will arrive for Monday with highs in the 70s. A few showers will be possible in southern areas as the upper level low lingers just offshore. High pressure builds in on Tuesday with quiet and seasonable weather into Wednesday. The high slides offshore Wednesday night into Thursday returning a chance for showers and increasing heat and humidity. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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5 PM...The broken line of convection that run runs from near KBGR SW to into Sullivan county NH is the line between the very unstable air S and more stable air to the N. While there are TSRA moving into this area ahead of the front, these storms are not expected to be severe, and have adjusted the watch to just include those areas along and S of that line. Severe thunderstorm watch in effect through 8 PM. A hot and humid airmass has brought heat inidices into the 90s across much of the region. The cirrus from BOX storms has alleviated the heating across southern counties and help limit the instability. Afternoon special sounding indicated poor midlevel lapse rates, a limiting factor for the potential severe magnitude. As heating continues, new cells will be able to harness building instability and an impressive amount of shear to continue the risk for severe thunderstorms. Damaging wind gusts remain the primary threat, but isolated hail is also possible. The risk will push offshore by 7-8 PM. Dew points and PWATs are high this afternoon with heavy rainfall in any storms, but the progressive nature of the storms will limit the risk for flooding. Strong cold air advection behind the front is bringing in a drier and much cooler airmass overnight. The drier air should inhibit fog for most areas, but valleys and recently worked over areas could see some patchy development.
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&& .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... The upper level low will drift offshore on Monday, and the cold pool aloft could support a few showers, best chances in near the coast and S NH. These showers will be limited in coverage and duration, while most of the area will remain dry but under mostly cloudy skies and cool northerly winds. High pressure over the Upper Great Lakes will make its way across our region Monday evening. Quiet and dry weather Monday night as high pressure moves through the region. Lows will be found in the upper 40s in the north to low to mid 50s elsewhere. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Enjoy the cool and dry start to the work week because heat and humidity will return. The area will be under the influence of a mid and upper level ridge through Wednesday, but an upper level trough will drive the ridge southward by Thursday. The surface high will slide offshore, with a warm front pulling in heat and humid air back into the region late Wednesday. This will likely be accompanied by showers in the afternoon. Southerly flow becomes more established leading to hot and humid conditions late week starting on the 4th. Aloft there will be fairly zonal flow, with a series of weak upper level troughs Thursday through Saturday. A pre-frontal trough could keep some showers possible Thursday, with a series of weak frontal passages that will support scattered showers and thunderstorm activity with low confidence on timing through the weekend. Despite any cold frontal passages, the overall airmass will remain warm and humid, fairly typical of July. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... Short Term...Increased risk of TSRA and sub-VFR conditions this evening. Highest confidence for TS at terminals are MHT, RKD, and AUG. Drier air moving into the region Sunday night favors VFR conditions into Monday. Long Term...VFR expected Monday night through Wed, with possible valley fog Monday night. Then more widespread flight restrictions possible Wed night into early Thu in SHRA/TSRA and some fog. && .MARINE... Short Term...Increased thunderstorm risk this evening. SCA conditions will wane overnight as winds slacken as a cold front passes offshore by morning. The cold front will help erode any lingering low stratus near the midcoast. N/NE winds will prevail on Monday with high pressure building over the region Tue- Wed...continuing quiet marine conditions. Long Term...Swell from Beryl will arrive late Wednesday into Thursday, bringing minimal rise in wave heights but could raise rip current risk. The high will drift east on Thursday with a warm front lifting north, bringing heat and humid conditions. The pattern remains unsettled under zonal flow by the end of the week into the weekend with the passage of weak frontal boundaries. Outlook... Monday through Thursday...Conditions are forecast to be below Small Craft Advisory criteria after this evening. && .GYX WATCHES/WARNINGS/ADVISORIES...
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ME...None. NH...None. MARINE...Small Craft Advisory until 11 PM EDT this evening for ANZ150- 152-154.
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&& $$ NEAR TERM...Cempa/Jamison