Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 242356 AAA AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 756 PM EDT SUN JUL 24 2016 .SYNOPSIS... A cold front will approach from the west on Monday and will cross the region Monday night, providing another round of showers and thunderstorms. High pressure will build in from the west Tuesday through Wednesday. A weak frontal boundary will settle south from Canada Wednesday night and will stall over the region on Thursday and perhaps Friday. The weekend may dry out if high pressure from the north suppresses the frontal boundary far enough south. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 7:50 PM Update... Temperatures are in the 70s except for a few exceptions over southern NH. Dew points have dropped into the 50s to near 60s along the coast. Models are entertaining a few spots of fog possible in the mountain valleys and have added patchy non-dense fog to these areas and also near Rockland. This will really depend on how far temperatures and dew points fall overnight...but Rockland is already carrying fog. Otherwise forecast is on track. Winds are already light and variable. Previous discussion... Sunny skies will continue this afternoon in the wake of yesterdays front. Radar returns show the seabreeze just beginning to push onshore at 18Z. Expect the seabreeze to make it to the middle of Cumberland county...allowing temperatures to cool a bit this afternoon. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... This evening skies will remain mostly clear. With considerable dry air aloft and dewpoints generally in the upper 50s expect little to no fog for the morning. After sunrise on Monday increasing clouds will move in as a short wave currently located over the great lakes approaches the region. Increasing southerly flow ahead of the front will push dewpoints back into the mid 60s across the area by afternoon...with southern New Hampshire seeing highs near 90 giving a heat index in the mid 90s. Hot and sticky airmass, and an approaching short wave will once again set the stage for thunderstorms Monday afternoon. Moisture will be plentiful as the higher dewpoints advect northwards. As far as instability most guidance hints at a region of steep lapse rates aloft approaching ahead of the short wave. Timing for the instability and trigger may be the critical issue. Fairly good agreement in the models of the short wave and accompanying jet streak and not arriving into western NH until around 5pm or later...which would result in limited instability by the time the shear and trigger arrives. The best chance for strong to severe storms will be across western New Hampshire in late afternoon. Dry mid levels will make gusty and potentially damaging winds the main threat although small hail is also possible as freezing levels drop back to around 10,000ft. Further east into Maine shower activity will likely hold off until after sunset, and while some thunder may develop the strongest storms will remain in NH for the daytime. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Cold front will move offshore Monday night bringing and end to shower and thunderstorm activity during the evening or early overnight hours. A drier air mass works in for Tuesday with fair weather likely except perhaps for a period of clouds and spotty showers near the Canadian border where there will be a little more influence from cooler cyclonic flow aloft. Wednesday should b e fair as well but perhaps a bit more humid. Above normal temperatures continue both Tuesday and Wednesday. Chances for showers and thunderstorms look to increase Thu and Fri as a frontal boundary nears and slows down. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... Short Term...VFR conditions expected through tonight. Looks like dewpoints will remain low enough to prevent fog formation. Monday afternoon increasing clouds but remaining VFR. HIE and LEB will see thunderstorms in the afternoon. Long Term...Some valley fog possible Monday night in the wake of showers and thunderstorms. Otherwise, VFR conditions are expected Tuesday and Wednesday, with increasing chances for some restrictions Thursday and Friday as a frontal boundary nears with increased chances for showers and thunderstorms as well as possible nighttime fog and stratus near the coast. && .MARINE... Short Term...All quiet on the waters through Monday. Only issue will be thunderstorms late Monday afternoon. Long Term...Winds and seas look to remain below SCA thresholds Tuesday through the end of the week. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Hanes SHORT TERM...Curtis LONG TERM...Ekster

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