Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 171344 AFDGYX Area Forecast Discussion National Weather Service Gray ME 944 AM EDT Fri Mar 17 2017 .SYNOPSIS... High pressure will build in from the west today providing dry but cool weather. High pressure will slide off shore Saturday as low pressure develops south of New England. This system will pass out to sea south of New England on Saturday night, but a few snow showers are possible. Warmer and dry weather are in store for Sunday through Monday. A cold front will cross the region Monday night followed by a secondary cold front Tuesday night. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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945 am update: Very quiet day with skies mostly sunny attm. Made some adjusments to sky cover to go with clear conditions thru the rest of the day across most areas. In the mountains some clouds expected to develop early this afternoon due to differential heating and very weak approaching upper s/wv. In put latest msonet data for next few hours and no other changes needed attm. Update...Minor changes to reflect latest observational trends. Previous discussion...Upper low continues to keep the region in cool...cyclonic flow. Lingering low level moisture is leading to some upslope clouds and patches drifting over the mtns and downstream to the coast. Can not rule out some snow showers...especially NW of the mtns. Where it has cleared out...temps have been able to get into the single digits. Cloudy areas remain in the upper teens and 20s. Gradually the low level moisture dries out today...with clouds being more likely to the E and closer to the upper low. As high pressure tries to nose into the area...mixing will be on the shallow side. So despite mid level temps warming a few degrees we may not be able to realize those temps. That may be enough to continue the sub-freezing streak going on across the area.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... Surface ridging tonight should allow for clear and calm conditions. I undercut guidance temps as a result...and with fresh snow on the ground some well below normal temps are likely. Sat upper trof digs S of New England. Flow becomes onshore S of PWM. With mid level temps around -10C and water temps around 3 or 4C...enough differential exists for some ocean effect snow showers. I have introduced some slight chance PoP for Srn NH...as these could bring a very light snowfall late Sat despite low pressure being well to our S. && .LONG TERM /SUNDAY THROUGH THURSDAY/... The models are in decent agreement on the longwave pattern through late next week. We begin the period with a closed low over the northeast CONUS. This upper low will lift out early in the period with ridging and milder weather to follow for the start of the new work week. Unfortunately...digging shortwave energy will quickly carve out another upper trough over eastern Canada and the northeast CONUS for much of the second half of the work week. By Friday and the start of next weekend...warmer air arrives as the upper trough lifts out. The upshot of this pattern on sensible weather will be a veritable roller coaster in temperature this period. Temperatures rebound to normal of slightly above normal values early in the period...only to see a return to well below normal temperatures for the second half of the new work week. In the dailies...the upper low and an associated surface low will pass close by to our south and east Saturday night and Sunday. Areas along the Massachusetts border as well as extreme southwest coastal Maine could get brushed by the northern periphery of the precipitation shield with this storm system. At this point...it looks like any accumulation there would be a dusting to an inch. Elsewhere...we should see little if any precipitation. A ridge of high pressure and slightly milder air will follow for Monday. Tuesday will be the mildest day of the work week before a series of cold frontal passages reintroduce much colder air into the area for the second half of the work week. High pressure will build east and crest across the region on Thursday before retreating offshore by Friday. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... Short Term...Widespread VFR conditions expected thru Sat. Cyclonic flow continues over the mtns...and some scattered MVFR CIGs are possible as the low level moisture slowly dries up. Then late in the day Sat...onshore flow may brings some MVFR in ocean effect SHSN to Srn NH...mainly PSM and MHT. Long Term... Sun...Sct MVFR psb vcnty KPSM in -shsn. NE sfc wnd gusting to 25 kt at cstl TAF sites. Tue...Sct MVFR in mtn -shsn. && .MARINE... Short Term...Winds and seas continue to diminish as low pressure pulls away from the area. SCA for hazardous seas is no longer in effect as seas have dropped below 5 ft across the coastal waters. Long Term... Sun......Gales are likely. Mon...A Small Craft is psb outside the bays. Tue...Gales are likely, with a Small Craft for the bays. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$

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