Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 240108 AFDGYX Area Forecast Discussion National Weather Service Gray ME 808 PM EST Tue Jan 23 2018 .SYNOPSIS... Temperatures have struggled upward all day...finally reaching near freezing. After widespread freezing rain of one to two tenths...precipitation is coming to an end from west to east late this afternoon and early this evening. Any remaining showers will transition to snow in the mountains...while to the south dries out. Temperatures will remain fairly steady this evening...climbing with the cold front around midnight before slowly falling towards sunrise. Near normal temperatures are expected Wednesday...with much colder overnight temperatures Wednesday night. High pressure builds in for the remainder of the week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 805 PM Update...Have allowed the remaining winter weather advisories expire on time at 8 pm. Most locations have risen to between 32 and 33 degrees at this time. However, we do expect many slippery areas to continue overnight - especially in areas that clear out after midnight and the winds stay calm. This could lead to a quick refreezing of some surfaces - especially secondary roads, parking lots, and sidewalks. In the meantime we do have one more band of mostly rain to move through. This will move through quickly - likely lasting around 1 hour at any given location through 03-04z and could be accompanied by an isolated rumble of thunder. Winds may pick up somewhat with or immediately behind this band which could cause some more branches to fall and cause power outages. 610 PM Update...Have updated mainly PoPs for the next 3 hours or so as a strong short wave trough will swing through with a relatively short-lived band of showers. This can currently be seen near the NY/VT border. The latest run of the HRRR has a pretty decent handle on it, so updated the PoPs to reflect the HRRR for the most part. Most locations are at or just above freezing at this time, so this should mainly be in the form of rain. However, some spots are still just below freezing (especially in the advisory area) so some additional minor ice accretion will be possible until about 03z or so. Thereafter, a clearing trend is expected. Otherwise, have cancelled the wind advisory for the mid coast, as 40 kt gusts are not foreseen at this point. 5 PM Update...Have extended winter weather advisories until 8 pm where temperatures are still around or just below freezing. This includes interior portions of our Maine zones and Carrol County NH. Have cancelled Coos County as most areas are now above freezing. In any event, the precipitation will come to an end over the next couple of hours, with power outages possible through that time. Previously... Back edge of the precip has reached the CT River Valley this hour...and will continue to pull Ewd into the late afternoon/early evening. WAA and latent heating has pulled surface temps up to just about freezing in most locations. There are pockets...especially across the interior of Wrn ME...that remain below freezing and will continue to see occasional freezing rain into the early evening. For that reason the winter wx advisories there remain in place. Across Srn NH and coastal Wrn ME I have allowed those advisories to expire. Where the warm front has made it onshore around Midcoast ME there remains a threat for strong Sly wind gusts. So far RKD has been fairly benign winds...but just offshore at MISM1 wind gusts above 40 kts have been observed. I will keep the wind advisory in effect for this threat. Temps should remain fairly steady into the evening ahead of the approaching cold front...back across central NY. The upper level front is quickly moving E...with dry slot bringing some clearing to far Wrn zones before sunset. With the approach of the front...deeper mixing will help overturn the low level cold and temps should rise to their daily max around the 06z time frame. Temps slowly fall after that...with strongest CAA delaying until Wed. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... Wly CAA flow will dominate Wed and Wed night. Temps are not expected to rise too much from morning readings Wed as the colder air moves in. Winds may gust as high as 30 knots at times in the afternoon. I would not be surprised to see this lead to a few scattered outages in places where ice remains stuck to tree limbs. Temps continue to fall overnight...but gradient winds will keep readings closer to model raw 2 m temps than cooler MOS values. Upslope snow showers will continue thru the day and into the overnight with some light accumulations in the higher terrain. && .LONG TERM /THURSDAY THROUGH TUESDAY/... The deterministic model solutions remain in decent agreement on the long wave pattern through the middle of next week. The pattern will remain progressive and begins to amplify with time. A steady progression of troughs and ridges across the forecast area will result in several sharp swings in temperature between well below and well above normal readings as we see a parade of disturbances cross the forecast area. In the dailies...A shortwave impulse will deliver a reinforcing shot of cold air to the area for Thursday and Thursday Night. The cold begins to ease on Friday as ridging and rising heights arrive. A warm front lifts north across the area Friday night with a southerly flow and well above normal temperatures arriving for the weekend. The more progressive GFS was again discarded as an outlier with the approaching frontal system in favor of the slower ECMWF/CMC- Global solutions...which bring the front and steadier band of precipitation across the forecast area late Saturday Night and Sunday. If the warmer ECMWF/CMC-Global are correct...then a multi day period of well above normal temperatures coupled with one to two inches of rain could cause some hydro issues given current ice jam situation. Colder air begins to filter into the area by Monday behind this system along with a return to below normal temperatures for the start of the new work week. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... Short Term...Widespread LIFR and IFR conditions remain entrenched across the forecast area early this evening. This will likely hold until the cold front can move thru and mix out the low level cold air. Some -FZRA remains...but will come to an end shortly as steady precip winds down and temps continue to warm. Otherwise all terminals may see some lingering -DZ and BR restrictions to VSBY thru the evening. LLWS is also coming to an end as the LLJ crosses the forecast area from W to E. It should be E of RKD by or just after 00z. Once cold front moves thru the winds become Wly and will help to dry out the low levels. VFR conditions are expected to quickly return late tonight. Upslope flow in the mtns will keep HIE MVFR with VCSH. Long Term... Sat Night - Sun...MVFR with areas of IFR in Rain and fog. && .MARINE... Short Term...Strong SCA conditions are expected thru Wed night. Long Term... Thu - Fri...Small Craft conditions are likely outside the bays. Sat...Small Craft conditions are likely...with gusts approaching gale outside the bays. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 9 PM EST Wednesday for ANZ150>154. && $$ NEAR TERM...Ekster SHORT TERM...Legro LONG TERM...Schwibs AVIATION...Legro/Schwibs MARINE...Legro/Schwibs

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