Area Forecast Discussion
Issued by NWS Portland, ME

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KGYX 182139 AFDGYX Area Forecast Discussion National Weather Service Gray ME 539 PM EDT Fri Aug 18 2017 .SYNOPSIS... A warm front will gradually push east of the region tonight. A slow moving cold front will cross the region Saturday. High pressure will build in from the west Sunday through Monday and will slide offshore on Tuesday. A cold front will move in from the west Tuesday night and will cross the region on Wednesday. High pressure will build in behind the front Wednesday night through Friday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Update... Have updated the grids based on current conditions and latest set of mesoscale models. Bands of heavy rain moved through many areas this afternoon. There has been a lull early this evening, however another batch of locally heavy rainfall will continue to spread eastward from southern New Hampshire this evening. Earlier, a report of an inch per hour occured with this precipitation. Another inch of rain in a few communities will bring storm totals locally into the 2 to 3 inch range. Highest totals so far today have been in coastal York County. Radar estimates are underdone for this area. An areal flood advisory will remain in effect through 7 pm for much of southern New Hampshire and far southwest Maine where the heavier echoes continue. The greatest threat will be for urban type flooding on roadways, culverts and low lying areas. Much of the precipitation will begin to taper off late this evening and become more scattered as best dynamics shift to the east. Made some minor modifications to the dew point, wind and sky cover grids for this evening. The rest of the forecast will remain relatively unchanged. Prev Disc... Warm front to the southwest continues to produce rain and rain showers mainly across southern zones. Rain will be occasionally heavy through the early evening hours as low level jet combines with PWAT`s of 2 inches or better sweeping through southern and coastal zones. Expect storm totals of 1 to 1.5 inches in southern New Hampshire and Coastal locations with locally 2 inch amounts in midcoast Maine. Rain will begin to taper off in these areas by mid evening and should clear most of the forecast area by midnight. Ocean stratus and areas of fog will blanket the region during the overnight. Lows will range from the mid 50s north to the mid 60s south. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Warm front will be quickly followed by a slow moving cold front on Saturday. As boundary layer winds turn into the west ocean stratus will gradually get shunted eastward during the morning hours although mid coast Maine may take much of the afternoon to break out. Marginal instability associated with the front will likely kick off afternoon showers and thunderstorms mainly across New Hampshire and western Maine where heating will be the greatest. Will be a fair amount of shear so some stronger cells may produce some wind damage but CAPES may be a limiting factor. Highs Saturday will range from the 70s in central Maine to the 80s in western Maine and New Hampshire. High pressure will build in behind the front Saturday night bringing clearing skies downwind of the mountains. In the north upslope flow and lingering moisture will result in mostly cloudy skies and possibly a stray shower. Lows will range from the upper 50s north to the mid 60s south. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Skies will become partly cloudy during the day Sunday as drier air moves into the region behind the front. There could be a lingering shower in the mountains early...otherwise, temps will warm to the mid 70s north to the mid 80s south as a ridge of high pressure builds into the area. The ridge will move offshore Monday and Tuesday as a cold front slowly approaches from the west. This will lead to increasing temperatures and humidity for Monday and Tuesday. High temps Tuesday will mainly range from near 80 in the mountains to near 90 in southeastern New Hampshire and extreme southwestern Maine. Along with the warmer temps and higher humidity, the threat of showers and possible thunderstorms will be on the increase Tuesday afternoon through Wednesday as a cold front approaches and crosses the region. Showers could linger Wednesday night. Cooler and drier air following the front for Thursday and Friday as surface high pressure builds into the region. With the colder air moving in aloft and an upper level trough developing over the area Thursday and Friday, an afternoon shower can`t be ruled out, especially in mountain areas, but most areas should be dry. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... Short Term...IFR/LIFR ceilings and vsby overnight. Gradually improving to VFR Saturday. VFR Saturday night with areas of IFR/LIFR in valley fog. Long Term...Mainly VFR conditions for Sunday into Tuesday with IFR conditions possible in valley fog early in the mornings. MVFR to IFR conditions likely Tuesday night and Wednesday in showers and possible thunderstorms. && .MARINE... Short Term...Continuing SCA`s for tonight through Saturday. Long Term...Winds should be diminishing and seas subsiding Sunday and Monday and will be below SCA criteria through Tuesday. Winds and seas will be increasing late Tuesday with SCA conditions possible Tuesday night and Wednesday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 8 PM EDT Saturday for ANZ150-152- 154. && $$ NEAR/SHORT TERM...Cannon is the U.S. government's official web portal to all federal, state and local government web resources and services.