Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 301513 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1113 AM EDT MON MAY 30 2016 .SYNOPSIS... A front stalled to our south will return north as a warm front today. This front will be preceded by showers and a few thunderstorms through Monday morning. A warm humid air mass will follow the warm front on Monday afternoon with another round of showers and thunderstorms expected. Tropical moisture from the remnants of Bonnie will be entrained in the frontal system and could produce heavy rainfall and localized drainage flooding on Memorial day. Two cold fronts will cross the area Monday and Tuesday night with high pressure to follow Wednesday and Thursday. An upper level trough could produce some rain towards the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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1110 am Update...Have updated pops and temperatures based on latest trends. Any steady light rain will be gone soon and the sun will start to come out resulting in warming temperatures. Widely sct storms may develop late this afternoon across the interior with attendant threat of gusty winds and small hail. Latest guidance suggests the best chance of storms today will be over southernmost NH and perhaps the western ME mountains. Overall it is not looking widespread. 845 am Update...Have updated the forecast a bit mainly for pops over the next several hours based on latest trends in radar data as well as mesoscale model data. Last band of steadier light rain currently centered across southern NH will move across southernmost maine in the next 1-2 hours. Otherwise, mostly dry until widely sct showers and storms develop this afternoon. Previously... 5 am ... just a quick adjustment to the PoP as radar shows rain moving into New Hampshire a bit faster. At 3 am... an area of rain was crossing Vermont and Southern New England into southwest New Hampshire. This rain will continue to move northeastwards crossing the southern portion of the forecast area early this morning. The rain is being driven by two factors. To the south, the remnants of Tropical Depression Bonnie is streaming moist tropical air northward on the west side of a Bermuda high. Satellite shows PWAT values as high as 2 in in this air mass with values around 1.5 inches across much of New England. To the west a short wave trough is moving out of the Great Lakes into western New York. These two systems are creating a squeeze pushing the moisture northwards up the coast. While PWAT is high... the area of rain is now mainly stratiform forced by the synoptic squish and thus the concern of heavy rainfall has abated as the rain continues to move. The early morning timing will also keep any convective threat to a minimum. Today will be a bit of a paradox as rain creates sun which in turn creates rain again. Ahead of the early morning rain the marine layer is well entrenched along the coast with widespread drizzle and fog. The morning rain will serve to move the marine layer out allowing sun to break out from west to east across the region this afternoon. The sun will subsequently destabilize the region...allowing a line of thunderstorms to form along the front which will cross the area late today. The thunderstorms will form around mid afternoon as temperatures rise to near 80 in interior New Hampshire and the CT river valley. CAPE values of up to 1000 J/kg combined with an 80kt jet streak overhead will generate sufficient shear for a few severe thunderstorms to develop with damaging winds and small hail being the main threats.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... Overnight skies will clear and showers and thunderstorms will die off as the front moves out of the area. Residual moisture will allow patchy fog to form...especially in favored valley locations. Tuesday will be mostly sunny with just a slight chance of upslope showers in the afternoon in the mountains along the Canadian border. Light northwesterly flow in the wake of the front will be enough to keep the sea breeze at bay allowing temperatures to climb into the 80s for all but the immediate coastline. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Dry weather will continue into the midweek as high pressure gradually builds in behind the departing front. Weak northerly flow will veer to the east by Wednesday afternoon bringing in a sea breeze. Temperatures should reach the 70s however with inland areas a few degrees warmer than the coast. Onshore flow strengthens Thursday with perhaps some drizzle... stratus... and fog allowing readings to only reach the 60s for much of the area. The remnants of the very weak TD Bonnie will move off the Carolinas Thursday night allowing a baroclinic zone to shift towards the eastern seaboard. This will introduce some heavier showers for Friday into the weekend with highs once again in the 60s and 70s. During this time overnight lows will be in the 40s and 50s...or in a word...normal. && .AVIATION /15Z MONDAY THROUGH FRIDAY/...
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Short Term...Conditions will improve to VFR across the area by 18Z. This afternoon scattered thunderstorms and showers may impact HIE LEB CON and MHT. Tonight expect valley fog for LEB and to a lesser extent HIE CON. All areas will be VFR for Tuesday. Long Term...VFR for Wednesday. Some MVFR along the coast Thursday in drizzle...stratus...and fog. -SHRA Thursday evening into Friday for all terminals bringing ceilings and visibilities down to MVFR and/or IFR.
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&& .MARINE...
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Short Term... Fog may lift somewhat mid afternoon before returning overnight. Winds and seas will remain below small craft. Long Term...Generally poor boating conditions from Thursday through the weekend in fog and drizzle as well as showers. Winds and seas will remain below small craft criteria.
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&& .FIRE WEATHER... Winds will remain light through the next few days with cooler temperatures and precipitation in the forecast the next two days. This will help keep fire danger in check. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Ekster SHORT TERM...Curtis LONG TERM...Hanes

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