Area Forecast Discussion
Issued by NWS Portland, ME

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973 FXUS61 KGYX 221444 AAA AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 944 AM EST Wed Feb 22 2017 .SYNOPSIS... A weak cold front will stall over the area today...with rain showers along it drying up. Low pressure moving east through southern Canada will drag the boundary back north as a warm front...leading to a mild night and even warmer temperatures Thursday. Highs will climb into the 50s to near 60 across New Hampshire...with 40s to near 50 over western Maine. A cold front will cross the area with rain showers Thursday evening. Once more that boundary lifts north as a warm front Friday night as we await a stronger cold front and more widespread precipitation over the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 945 am Update: Some lower clouds trapped in the Merrimack and CT River valley areas of NH otherwise skies clearing nicely elsewhere. A nice day in store. Only minor tweaks to temps and clouds based on latest obs and Satellite imagery other no other changes at this time. Update...Minor changes to reflect latest radar trends. I have adjusted PoP to reflect that most precip is either over the coastal waters or confined to the highest terrain. Previous discussion...An area of rain showers along a decaying cold front is pushing thru Srn and central NH and extreme SWrn ME this morning. Temps have very slowly slipped down towards freezing thru the night...but most areas remain above 32. However...dewpoints are generally below some wetbulb cooling or pockets of near surface sub-freezing air is possible and could lead to localized freezing rain. The biggest hinderance to icing this morning may be that the rain showers are just too light to coat surfaces. NEAR TERM...Legro SHORT TERM...Legro LONG TERM...Schwibs AVIATION...Legro/Schwibs MARINE...Legro/Schwibs Otherwise...we will warm up again nicely today. Temps should climb into the 40s for most areas...and maybe even a few low 50s across Srn NH. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... The washed out cold front begins to drift back Nwd tonight as a warm front...ahead of a fast moving s/wv trof moving thru Srn Canada. We will have to keep an eye on dewpoints climbing thru the it could lead to some fog over the colder snow pack. Also behind the advancing warm front will be some of the very warm air mass that could be responsible for several more broken records over the Midwest today NEAR TERM...Legro SHORT TERM...Legro LONG TERM...Schwibs AVIATION...Legro/Schwibs MARINE...Legro/Schwibs . Steep lapse rates aloft within this air mass will advect in overnight. Much like the late spring and early summer...the arrival of this steep lapse rate air may be enough for some WAA type showers late tonight or early Thu. SW flow behind the warm front and the moderating Midwest air mass will lead to very warm temps Thu. 50s should be pretty widespread across Wrn portions of the forecast area...with a few low 60s possible in favored Srn NH downslope areas. Those steep lapse rates remain in place Thu...and within the warm sector ahead of approaching cold front. I expect a convective line of showers to develop along the front as it advances Ewd Thu afternoon. Model CAPE forecasts are fairly meager at this time...but it would not surprise me to see a few stronger cells lead to a graupel shower or clap of thunder even. The showers will lose some punch with loss of daytime heating...but lapse rates aloft should sustain them to the coast thru early evening. && .LONG TERM /THURSDAY NIGHT THROUGH TU NEAR TERM...Legro SHORT TERM...Legro LONG TERM...Schwibs AVIATION...Legro/Schwibs MARINE...Legro/Schwibs ESDAY/... The models are in decent agreement on the longwave pattern through late next week. While we`ll see some brief intrusions of colder air into the region...ridging and above normal temperatures are expected to dominate the extended period. In the dailies...a weak impulse will cross the area Thursday night with an associated surface low passing down the Saint Lawrence and a trailing cold front crossing the area with a few rain or snow showers in the higher terrain. High pressure briefly builds by to our north on Friday. However...warm air advection clouds and light precipitation should spread north and east across the area during the afternoon and evening hours. The warm front will lift north across the area on Saturday as an impulse over the upper Midwest pushes a surface low northward across the Great Lakes. This low will drive a strong cold front across the area Saturday night with more seasonable air and upslope snow showers to follow for Sunday. Another quick moving impulse will race eastward along the U.S. Canadian border and drive a second cold front across the area on Monday accompanied by a second round of upslope snow showers. A weak ridge follows for Monday night. By Tuesday, warmer air returns in broad west- southwest flow aloft. Both clouds and pops will increase in warm air advection ahead of a disturbance expected to track to our north and west down the Saint Lawrence mid week. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... Short Term...Some local MVFR possible this morning near decaying cold front edging towards the coast. It will lift back N tonight as a warm front...and increasing dewpoints over the snow cover may lead to some fog development. Confidence is low in occurrence at this time. Tonight into Thu morning some -SHRA are possible along the advancing warm front...though low probability precludes mentioning in the TAFs just yet. Late Thu afternoon a cold front approaching the CT River may bring -SHRA to LEB...HIE...and CON before reaching the coast around or just after 00z Fri. Long Term... Fri AM...Sct MVFR psb in mtn -shra/-shsn. Fri PM - SAT...MVFR in -shra with areas of IFR in drizzle and fog. SE sfc wnd Sat gusting to 30 kt. Sun...Sct MVFR in mtn -shsn. NW sfc wnd gusting to 25 kt. && .MARINE... Short Term...A few gusts just below SCA thresholds this morning ahead of the cold front will diminish by afternoon. A warm front lifts N across the waters tonight...with winds and seas remaining below SCA conditions. SWly flow Thu will begin to build seas to near 5 ft by evening. Long Term... Fri AM...SCA`s likely outside the bays. Sat - Sun...SCA`s likely...wth gusts approaching gale outside the bays. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ is the U.S. government's official web portal to all federal, state and local government web resources and services.