Area Forecast Discussion
Issued by NWS Portland, ME

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276 FXUS61 KGYX 210315 AAC AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 1115 PM EDT WED JUL 20 2016 .SYNOPSIS... High pressure will move to the southeast of the Maine and New Hampshire tonight. A warm front will approach the southwest Thursday night ushering in much warmer and humid air. A cold front will approach Friday and move off the coast Saturday morning. A secondary cold front will move through the area Saturday afternoon ushering in some slightly less humid air. High pressure will build overhead Sunday. Warmer and more humid air will return Monday with a cold front moving through late Monday night. && .NEAR TERM /THROUGH THURSDAY/...
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Update...A few minor changes to temps and dewpoints overnight. Keeping an eye on low temps in the far N...where decoupling may allow for a few readings in the 40s again. I bumped min temps down a couple degrees in these zones. Previous discussion...A fine night on tap for tonight. Low temperatures will be similar to last night. Expect the cumulus to dissipate after sunset. I do expect some patchy fog to form overnight after 06Z.
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&& .SHORT TERM /THURSDAY NIGHT/... After any fog burns off in the AM Thursday looks like a fine day but warm with high temperatures climbing into the mid to upper 80s south of the foothills. The saving grace will be the dew points will only rise into the mid to upper 50s. The very humid air will stream in Thursday night with dewpoints in the 60s by Friday morning. There is the chance of showers and maybe a thunderstorm late Thursday night or early Friday morning as this warm and humid air streams in. Low temperatures Thursday night will only drop into the mid and upper 60s in southern locations. It will feel very unpleasant out there by Friday morning. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... High impact weather: Strong to severe thunderstorms possible Friday afternoon. Friday begins with a very strong ridge of high pressure in the central CONUS. Northern New England remains on the periphery of the high with disturbances moving across the top of the ridge into our area. The ridge breaks down towards the end of the weekend allowing a more progressive flow to move in. Friday morning a warm and humid airmass will be in place across northern New England. Southerly flow will bring dewpoints into the low 60s and allow temperatures to climb to near 90 in the south. Aloft a short wave will move in around 18Z... helping to touch off thunderstorms. MUCAPE values range from around 1500-2000 J/kg as a region of steep mid-level lapse rates moves in providing plenty of instability and moisture for thunderstorms. Severe thunderstorms are possible as a 50-60kt tropopause jet will help to support storm top divergence and a lower level jet of around 40kts at 3km will result in increased surface shear. While winds aloft remain westerly the mountains will help to channel the surface level winds more southwesterly in the coastal plain increasing the wind shear. With all the progs pointed to the potential for severe storms Friday afternoon have added the gusty winds and small hail wording. The only concern would be for early morning or overnight thursday convection to result in more clouds which would limit surface heating and destabilization and this uncertainty kept the severe wording out of the grids for now. Friday night convection will decrease after midnight as the upper level disturbance moves out. Saturday will see a few scattered showers and thunderstorms as the trough moves overhead. Some spread in the coverage of showers between the deterministic models but have hedge PoP a bit lower due to the westerly flow. Sunday a weak high builds in with clear skies and no precipitation. Another cold front approaches from the northwest on Monday afternoon which will again touch of thunderstorms. Strongest lapse rates look to remain a bit to the west so will go with just scattered thunder. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... Short Term...Expect VFR tonight except IFR possible at LEB and HIE in fog. VFR expected Thursday. MVFR may move in Thursday night in any showers. Long Term... Thunderstorms will impact all terminals on friday afternoon with gusty winds and small hail. VFR conditions remain through the weekend with the next chance of IFR late Monday afternoon in rain. && .MARINE... Short Term...Winds and seas will remain below SCA criteria but will be increasing Thursday night. Long Term... Scattered thunderstorms will impact the waters on thursday night. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Legro

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