Area Forecast Discussion
Issued by NWS Portland, ME

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339 FXUS61 KGYX 221354 AFDGYX Area Forecast Discussion National Weather Service Gray ME 954 AM EDT Sat Apr 22 2017 .SYNOPSIS... Cool and unsettled weather will continue today as low pressure remains across the area. High pressure and drier air will finally build into the region on Sunday. A cold front will cross the region Sunday night into Monday. Low pressure will move up the Eastern Seaboard Tuesday and Wednesday. A cold front will cross the region Thursday, followed by high pressure on Friday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 945 AM Update...Most steady precipitation has exited the region as of early this morning. However, plenty of clouds and drizzle are hanging around and should do so much of the day, especially on the coastal plain. In addition, high temperatures are once again expected to be below normal. In addition, a short wave trough approaching from the west will likely aid in the development of at least of scattered showers across western zones this afternoon. 630am update... Shower activity has been decreasing and I have lowered the pop a bit. Fog still remains in the coastal plain but conditions are starting to improve in western NH. prev disc..A line of showers extending across coastal Maine this morning will slowly clear to the east through mid morning. Behind this line low level moisture remains back through the NH border with pockets of drizzle, fog and low clouds. The drizzle and fog will dissipate in the morning but the overcast skies will remain as the region is stuck between two low centers, one passing south of Long Island and one near Quebec City. While PoP will remain fairly low through the day the low clouds and drizzle will make for a damp cool day. Temperatures will remain in the 40s everywhere except along the Massachusetts border in southern NH where the dry air may manage to sneak in enough to result in some late day clearing. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... Overnight the dueling lows move off to our east allowing west flow to develop across the region with gradually drying conditions. Expect some valleys may trap the moisture resulting in patchy fog overnight but as a whole conditions should be drier as we move into Sunday and high pressure approaches. The one exception may be the mountains where the west to northwest flow may be just enough to instigate a few isolated showers tonight. Sunday high pressure will build in as skies become mostly sunny. This will allow for afternoon high temperatures to reach 60F across much of the interior. Along the coast, this same weak pressure gradient will mean a sea breeze will develop in the afternoon keeping high temperatures in the upper 40s along the midcoast and just reaching 50 along the south coast of ME and NH. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... A weak cold front will enter northern portions of the forecast area on Monday, before stalling out. This front will be relatively moisture starved so expect any precipitation to be widely scattered, light, and confined to far northern areas of the mountains. Temperatures ahead of this front will top out in the 60s during the day Monday as H8 temperatures reach about +4C during the afternoon under a light southwest flow aloft. Readings along the shoreline will likely be cooler with a weak onshore flow developing. Some differences continue run to run and model to model in the track and evolution of a coastal system during the midweek period next week. Low pressure begins to move northeastward on Tuesday from the North Carolina coastline. The surface low gradually fills while the upper level system opens and lifts northeast with time. The GFS and Euro are quicker lifting this weakening system to near the 40N/70W benchmark on Wednesday, while the Canadian Model keeps more vigorous energy locked further to the south and closer to the Mid Atlantic coastline. Differences noted in the model ensembles as well as the the progression and negative tilt to the system. In any case, a cold front is expected to cross the region Friday, followed by a brief return of high pressure to New England Saturday. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... Short Term...IFR Fog drizzle will persist today on the coastal plain and perhaps even MHT. By Afternoon western areas will be in MVFR with overcast skies but not much in the way of precipitation or obscuration. IFR conditions possibly persist overnight on the coastal plain, but will revisit this possibility for the 18z TAFS. High pressure building in from the west results in conditions improving to VFR for Sunday. Long Term...VFR conditions are expected Monday night. Deteriorating conditions (MVFR to IFR) are once again expected to develop by Tuesday afternoon and last through Wednesday in rain/low clouds. && .MARINE... Short Term...SCA conditions will continue on the ocean waters today, especially eastern waters. High pressure builds in for the weekend keeping conditions below SCA. Long Term...SCA conditions will be possible Tuesday through Thursday as low pressure moves off the Eastern Seaboard. .FIRE WEATHER... Moist conditions will continue today with some drying possible Sunday. && .TIDES/COASTAL FLOODING... Very high astronomical tides will occur as low pressure passes by off the coast Tuesday into Wednesday. Minor, nuisance coastal flooding is possible during this period under a northeast flow. Highest Storm Surge values briefly approach one foot per the latest ESTOFS run. Nearshore waves are currently only forecast to top out in the 5 to 8 foot range during this period, so again, impact should be minimal. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 4 PM EDT this afternoon for ANZ150- 152-154. && $$ NEAR TERM...Ekster

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