Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 160227 AFDGYX Area Forecast Discussion National Weather Service Gray ME 927 PM EST Thu Feb 15 2018 .SYNOPSIS... Weak low pressure moving through Quebec will drag a cold front south across the area late tonight and early Friday. Another low will track east along this front overnight into Friday morning. This will bring some rain mainly to southern areas tonight with rain and a few snow showers elsewhere. Gusty northwest winds behind this front will introduce much colder air to the region late Friday and for the start of the upcoming weekend. The coldest day will be Saturday as cold high pressure moves across the area. Low pressure south of New England may spread snow into the region Saturday night and early Sunday. Strong ridging develops over the western Atlantic, which will bring warmer air into the region next week, but also unsettled conditions. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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925 PM Update...Have updated temperatures and sky cover for the next few hours as well as PoPs overnight based on latest trends and mesoscale model data. Mostly clear skies are persisting across central and eastern zones this evening. Have adjusted skies and temps for this. Eventually clouds will overspread the region after midnight and temperatures should come up a bit. Have continued the mention of patchy fog all zones given moist low levels. Otherwise, light rain (generally less than a tenth of an inch) is expected after 06z tonight across southern zones. Have updated PoPs to be more in line with last several runs of the HRRR. 615 PM Update...Have adjusted temperatures, sky cover and weather overnight based on latest trends in observational and mesoscale model data. Currently seeing a break in the clouds at many locations across the forecast area early this evening. Should radiate some in these areas at least until the next batch of clouds arrives. With the low levels being moist, we can expect the development of patchy fog shortly. Otherwise, showers well after midnight in the far south with little northward extent of measurable expected across central and northern zones. Previously... At 19z...a 997 millibar low was over western Quebec will a warm front through northern New england and a trailing cold front through the upper Great Lakes. GOES imagery showed broken to overcast skies across the region with mild southerly flow boosting temperatures into the 40s with some lower 50s for southeast New Hampshire into adjacent interior southwest Maine. For tonight...an unseasonably mild night with some areas of drizzle and fog developing. We`ll see showers develop overnight in advance of the cold front with a few post frontal snow showers across the mountains towards morning as the column begins to cool.
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&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... On Friday...the cold front sweeps southeast and off the coast by afternoon accompanied by a few rain showers. The mountains will continue to see a few post-frontal snow showers in the upslope flow with several inches of accumulation likely. Gusty northwest winds will develop behind the front with high temperatures in the morning along the international border and around midday along the coast before strong cold air advection causes temperatures to fall off. Morning clouds will give way to some afternoon sunshine downwind of the mountains and downslope flow takes hold. Highs will range from the 30s across the mountains with 40s and a few lower 50s elsewhere. Clearing and cold with diminishing winds Friday Night as high pressure builds in from the Midwest. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Fro the most part, we will continue with a 500 MB pattern across the nrn that is, for the most part, weakly amplified, with only weak transient blocking equatorward of 50 N. So, after a brief trough moves through over the weekend, when we`ll deal with colder air and some snow, should see temps running mostly above normal next week, and perhaps well above normal Tue or Wed. Saturday will start cold and sunny with highs reaching into the 20s inland, and generally 30-35 on the SW ME coast and in the warmer areas of srn NH. Clouds will increase during the afternoon, but probably not until late. Fast moving wave in WSW flow tracks out of the plains and into the OH vly late Saturday, and may phase with another wave in the nrn stream. Models continue to trend the developing sfc low S of New England. Today`s 12Z Euro is a bit more aggressive with QPF as the system moves through Sat night, developing some some good UVV in coupled jet entry exit region. However, both the GFS and the Euro operational models have lacked run to tun consistency, so will not bite on anything until a trend develops. The Euro ensemble has been more consistent, with overall 1-3" of snow, with slightly more over srn NH. This also matches the going forecast so will hold here for now. The impact period for this snow will be Saturday night, probably late evening into early Sunday morning, with snow winding down 12-15Z. Lows will drop into the upper teens N to the mid to upper 20s in the south. On Sunday, skies should clear out late morning to early afternoon, with highs rising into the 30s and low 40s, so should see some melting. Sunday will be clear with lows 15-20 in the N to the mid 20s S. On Monday, will see the SW flow begin to develop and temps will warm a bit on Monday, although a warm front will bring clouds in and some RA/SN showers Monday night, although not much, if any accums are expected. Tue/Wed look to be well above normal, particularly if you believe the Euro, which has been quite consistent with this warm up, so will be giving it more weight. It brings 850 MB temps of around 10C into the CWA. Onshore flow and clouds will likely limit full mixing potential, but widespread highs in the mid 40s N to low to mid 50s S are possible both days, and there is some potential to crack the 6o mark in srn zones if we see more sun and the SW flow keeps the marine air at bay either day. There will be a threat of showers in this time frame, mainly in the mountains as stationary front lingers near the St. Lawrence valley, but timing of waves along the front is problematic this far out. Should a return to closer to normal temps later in the week as a front moves through Wed night. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... Short Term /through Friday night/...Conditions deteriorating to MVFR with areas of IFR tonight in -shra and areas of drizzle and fog. Conditions improving to VFR in all but mtn sections by afternoon behind a cold front. Lingering MVFR and lcl IFR in mtn -shsn through Fri evening. NW sfc winds behind the front will gust up to 30 KT Fri afternoon and evening. Long Term...IFR in SN expected Sat night, especially in srn NH and coastal ME, although improvement to VFR expected by midday Sunday. Mainly VFR through Tuesday, although could see some tempo flight restrictions showers Mon night. && .MARINE... Short Term /through Friday Night/...Southerly flow will be replaced by strong post-frontal NW winds on Friday with gales likely Late Friday into Friday Night outside the bays/strong SCA`s for bays in strong cold air advection with light freezing spray returning for Friday Night. Long Term...Winds will approach SCA Sat night into Sunday morning, but otherwise should see sub-SCA conds through Tuesday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory from 4 PM Friday to 7 AM EST Saturday for ANZ153. Gale Warning from 6 PM Friday to 7 AM EST Saturday for ANZ150>152-154. && $$ NEAR TERM UPDATE...MLE

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