Area Forecast Discussion
Issued by NWS Portland, ME

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KGYX 261930 AFDGYX Area Forecast Discussion National Weather Service Gray ME 330 PM EDT Thu Apr 26 2018 .SYNOPSIS...
-- Changed Discussion --
Low pressure exits into the maritimes tonight allowing clearing that will last into early Friday. A large upper trough will move east from the Great Lakes and become centered over the region Friday night through the weekend bringing cool and unsettled conditions at times in the form of scattered showers that will be most numerous in the afternoon and evenings both Saturday and Sunday. The system will begin to exit the region late Monday. A warming trend is expected to begin Tuesday on a developing southwest flow.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
-- Changed Discussion --
As weakening 500 MB trough crosses New England this afternoon could set off a few scattered showers, especially across the foothills and coastal plain of western and central ME, where lingering surface Tds in the 50s and some sun could spark some convective showers through around sunset. So an isolated heavy downpour, and even some graupel, are possible as temps aloft are cool and freezing level is low. These will diminish with the sunset, as we lose daytime heating and the wave shifts to our NE. For tonight, any lingering showers will end quickly, with skies clearing out this evening. Temps should fall off into the upper 30s N to mid 40s S. Could see some patchy fog develop especially in the sheltered valleys as skies clear, winds subside and low level moisture lingers.
-- End Changed Discussion --
&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
-- Changed Discussion --
Friday morning will start mainly sunny but sun fades during the morning from SW to NE as a wave cruises around the base of a trough to our SW, and weak sfc low develops. Highs will be in the 60-65 range most places, but only in the mid-upper 50s on the coast as onshore flow develops in response to approaching system early in the day. Some showers will develop ahead of the system Friday afternoon, but a period of steady rain is likely to hold off until late in the day and mostly Friday night. The system is being sheared out in the SW 500 MB flow, so it will not be impressive, with QPF mainly around a quarter to a third of an inch or less. Low will mostly be in the 40s.
-- End Changed Discussion --
&& .LONG TERM /SATURDAY THROUGH THURSDAY/...
-- Changed Discussion --
...Uncertainty on arrival of warmer temps next week... Models showing a deep upper trof over the Great Lakes region digging southeast and becoming a broad closed upper low over New England over the weekend and into Monday. This will provide cool and unsettled weather. The most numerous showers will be in the mountains and foothills although all areas will have sct showers at times especially in the afternoon/evening hours each day. Any partial clearing during the daytime hours allowing surface heating will only steepen lapse rates and cause showers to become more numerous and enhanced, possibly causing some graupel in a few of the heavier afternoon showers. This is very common with upper low systems during late April into May across the Northeast. The euro is much slower in moving the upper low east and keeps it over the area through Tuesday while some other models are quicker in moving it east. Prefer the solutions that move it east by Tuesday allowing the ridge to the west to become progressive. With this all in mind will push back any warmer temps to Tuesday and best warming waiting now until at least Wed where h85 temps warm to +12C to +14C. If the Euro ends up correct then the warming trend will have to hold off even longer. For now will stick with the superblend guidance for temps which is a good hedge and does bring the warmer temps with the developing southwest flow on Tue.
-- End Changed Discussion --
&& .AVIATION...
-- Changed Discussion --
Short Term...VFR expected at all but KHIE this evening, with the possibility of some fog at KLEB/KHIE. VFR likely through most of Friday with MVFR or IFR returning in some light rain Friday night. Long Term...Variable conditions from VFR to MVFR in scattered showers over the weekend and thru Mon.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
Short Term...Have extended the all-purpose SCA for the outer waters thru tonight. It is mostly for seas at this point, but could see some W-SW winds gusting to near 25 kts, especially this evening. Seas will stay high through Friday and into Friday night. Long Term...Seas over the weekend will be slow to subside over the outer waters so a SCA for seas may be needed Sat into Sun.
-- End Changed Discussion --
&& .HYDROLOGY...
-- Changed Discussion --
Most rivers have or are cresting, and will be subsiding thru tonight. The Kennebec is the only exception with minor flooding expected at Skowhegan, and an outside chance for minor flooding at Augusta on Friday.
-- End Changed Discussion --
&& .GYX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
ME...None. NH...None. MARINE...Small Craft Advisory until 7 AM EDT Friday for ANZ150-152-154.
-- End Changed Discussion --
&& $$

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.