Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 020339 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1039 PM EST Thu Dec 1 2016 .SYNOPSIS... Low pressure will exit into the maritimes by early evening. In the wake of this disturbance, northwesterly flow will continue through the start of the weekend with snow showers in the northern mountains. Cold high pressure will settle in for the start of next week. Light overrunning precipitation could arrive Wednesday or Wednesday night. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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Update...Only minor changes to reflect latest observational trends. Albeit more difficult with darkness...webcams from our Nrn zones do show continuing signs of precip falling. So PoP was bumped up slightly again. major changes. Previous 19z...a 990 millibar low was over the downeast Maine coastal waters. An occluded front extended northwest from the low to a second 991 millibar low over western Quebec. NWS doppler radar mosaic showed scattered convection over the northern half of New Hampshire...otherwise precipitation had exited the area to our north and east. In the westerly flow behind the departing disturbance GOES imagery showed some partial clearing over eastern New Hampshire into adjacent western Maine. The cool westerly low level flow off the Great Lakes was transporting moisture into the higher terrain and should keep broken clouds across much of the Connecticut Valley northward through the international border area the remainder of today and tonight along with scattered rain or snow showers. There could be some light snow accumulations tonight across the higher terrain. Elsewhere...we should see scattered to broken clouds. Lows tonight should be in the 30s.
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&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... Little change to sensible weather Friday and friday night with the surface and upper lows remaining just to our north over Eastern Canada. The cool cyclonic flow and a low level trajectory off the Great Lakes should keep Connecticut Valley and the higher terrain of New Hampshire and western Maine mostly cloudy with a few rain or snow showers. Some light snow accumulations will remain possible across the higher terrain as well. Elsewhere...we`ll see partly cloudy conditions. highs tomorrow will range from the 35 to 40 in the mountains with 40s elsewhere. Lows tomorrow night will range from the upper 20s to lower 30s. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Cold cyclonic flow will start the long term period off - Saturday and Saturday night. Variable clouds are expected downwind of the mountains in a downsloping regime but upslope clouds and snow showers expected in the mountains. Saturday could be a bit breezy too - adding more chill to the air. Same general pattern holds for Sunday except the upper low moves off to the east and allows for lighter winds and more sunshine. A weak short wave trough will likely approach from the west for Monday. However, this trough will be dampening with time. By the time it gets there moisture and forcing will be limited - so we just went with a slight chance of snow showers. May end up just being flurries if anything. High pressure then settles overhead for Tuesday. Thereafter, forecast uncertainty is high and confidence in sensible weather is low come Wednesday and Thursday. Some model guidance over the last few days has pointed toward a coastal low possibly bringing a good shot of wintry precipitation during this time. However, there is considerable spread on how the upper air pattern over NOAM evolves, as well as the handling of an important short wave trough ejecting out of Mexico. Have not been able to see the 12z ECMWF as it is running late. 00z ECMWF and GFS ensemble guidance generally points toward a much more tame scenario with many members keeping any significant low pressure center well south of the region and leaving us with a period of light overrunning precipitation - if anything- instead. Again, low confidence forecast, but at this time it seems prudent to hedge toward the drier models until distant short wave troughs become better sampled. && .AVIATION /04Z FRIDAY THROUGH TUESDAY/... Short Term /Through Friday Night/...VFR...xcp lcl MVFR psb in Mtn -shsn. Long Term...MVFR conditions are expected in the mountains Saturday into Sunday morning with VFR conditions expected downwind from the mountains. A period of MVFR conditions is possible Monday in a little light snow - but probability is pretty low. VFR returns Tuesday. && .MARINE... Short Term /Through Friday Night/...Small Craft conditions linger tonight in westerly flow across all the waters. It`s likely we`ll see Small Craft conditions persist through the day Friday outside the bays. Long Term...A period of SCA conditions are possible on the ocean waters Saturday and Saturday night - possibly into early Sunday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 7 AM EST Friday for ANZ150>154. && $$ NEAR TERM...Legro is the U.S. government's official web portal to all federal, state and local government web resources and services.