Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 192338 AFDGYX Area Forecast Discussion National Weather Service Gray ME 738 PM EDT Thu Oct 19 2017 .SYNOPSIS... A cold front will cross the region tonight and will be followed by high pressure on Friday. High pressure will hold over the region on Saturday and will drift east saturday night and Sunday. A cold front will slowly approach from the west Sunday night and Monday and will stall to the west of the region Monday night and Tuesday. The front will slowly drift east Tuesday night and Wednesday. && .NEAR TERM /THROUGH FRIDAY/...
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730 PM...Just a quick update, mainly to show higher sky cover, with lots of cirrus, but very little of it is opaque, so more partly cloudy than mostly cloudy thru the evening. Once the front goes thru should clear out again after midnight. Also made a few adjustments to T/Td/wind based on currents obs, but overall forecast remains on track. Weak moisture starved cold front will swing through the region overnight with little more than passing clouds through the evening hours. Lows overnight will generally range through the 40s.
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&& .SHORT TERM /FRIDAY NIGHT/... High pressure will gradually build in from the west on Friday. Will see a slightly cooler day but temperatures will remain above normal. Should see a mix of clouds and sun in the north and mostly sunny skies south. Highs will range from the mid 50s to lower 60s north and mid 60s to near 70 south. High pressure will continue to build in from the west Friday night. Expect partly cloudy skies overnight with lows from the mid 30s north to the mid 40s south. && .LONG TERM /SATURDAY THROUGH THURSDAY/... This weekend an anomalous ridge will build along the East Coast Nwd thru Hudson Bay. Ensemble progs suggest the middle of the ridge will be around 3 standard deviations above normal for this time of year. What that means for sensible wx is continued much above normal temps and dry. Model guidance continues to push low teens H8 temps and mid teens H9 temps around the periphery of the surface high and into New England. Mixing should stay fairly shallow and remain around H9...but those temps still translate to widespread 70s and pushing 75+ in the warm spots. The multi- model consensus blend seems a little cool...especially into early next week...so I have increased temps a few degrees by mixing down H9 temps and blending in some MOS guidance. With deep...meridional flow developing early next week across the central CONUS...flow parallel to the front will tend to keep things slow moving. 19.12z model guidance did slow the arrival of precip compared to yesterday. So I have decreased PoP a little from the multi-model consensus Tue...with likely PoP reserved for Tue night/Wed. Late in the period deterministic and ensemble guidance is also trending towards a blocky pattern in the North Atlantic. This may keep the baroclinic zone just offshore and allow a focus for when the upper low ejects out of the Southeast. Consensus has trended towards a two part rainfall event...with the lead wave arriving midweek...and the upper low arriving late in the week. && .AVIATION /23Z THURSDAY THROUGH TUESDAY/...
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Short Term...Mainly VFR tonight into Fri night. Would not be surprised to see a little bit of vly fog very late tonight, more around sunrise, as some late decoupling may occur. As terminals go, best chc would be at KLEB, but not included in the TAF attm. Long Term...Widespread VFR conditions will continue under high pressure. High will be more centered overhead over the weekend...so valley fog and LIFR conditions will be possible at HIE and LEB. Return flow develops Mon into Tue...and that may keep things mixed enough to prevent fog in the valleys. Increasing moisture may lead to coastal stratus however.
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&& .MARINE... Short Term...Continuing SCA`s for the bays and outer waters. Long Term...As trof digs into the central CONUS early next week...developing Sly flow may build seas above 5 ft outside the bays. As Sly LLJ increases midweek...SCA are likely with seas approaching 10 ft. In general wind gusts should remain below 25 kts on the coastal waters until midweek. && .FIRE WEATHER...
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Relative humidities will drop into the upper 20s to mid 30s in southeast New Hampshire and southwest Maine tomorrow afternoon along with winds of 10 to 20 mph. This would come in just under meteorological RFW conditions, and will elevate the threat of wildfires.
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&& .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 6 AM EDT Friday for ANZ151-153. Small Craft Advisory until 6 PM EDT Friday for ANZ150-152-154. && $$ SYNOPSIS... NEAR TERM...Cempa/Sinsabaugh SHORT TERM...Sinsabaugh LONG TERM...Legro AVIATION... MARINE... FIRE WEATHER...

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