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 231340 AFDGYX Area Forecast Discussion National Weather Service Gray ME 940 AM EDT SAT JUL 23 2016 .SYNOPSIS... A cold front will slowly sag south through the region today and will push offshore tonight. High pressure will build in from the west on Sunday and will shift offshore Sunday night. A cold front will approach from the west on Monday and will cross the region Monday night. High pressure will build in from the west on Tuesday and will crest over the area on Wednesday. A weak cold front will slowly push southeast into the region Wednesday night and will stall over the region on Thursday. High pressure will build in from the north Thursday night and Friday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
9am... Just some minor tweaks to temps and dewpoints for this update. Looking ahead to the afternoon clearing skies in southern New Hampshire should allow for that area to heat up first. Morning sounding at KGYX shows a stable layer around 500mb... which should erode as the upper level trough in moves in out of Canada. Maniwaki 12Z sounding shows the layer almost gone with significant moistening in the mid levels. This will set the stage for good instability this afternoon. The best chance for strong to severe storms remains in southern New Hampshire where the heating will be maximized. Meanwhile the greatest coverage of storms will be more towards the Maine mountains where topography, moisture and last nights boundaries will coincide to assist storms in developing. 7 AM...no real changes to forecast thinking, with spotty showers starting pop up already in a few spots. Think for a few hours these will not amount to to much and fade as quickly as the developed, but as daytime heating builds and wave aloft begins to bring heights down, thunderstorms will start to develop laterthis morning. Previously...Last bit of remnant convection moving east along the mid coast and dissipating slowly. Should see a little break in the convection through mid-morning before daytime heating starts bubbling up convection again. Should start the day fairly sunny, except in the mountains, where there will be lingering clouds. As yet another 500 mb wave moves in from the west today will see showers and thunderstorms start to develop late morning to early afternoon, much earlier than on Friday. Will probably see more convection than on Friday, certainly closer to scattered than isolated. Thinking focus for best chance of storms will be in some of the same places we saw it Friday night as boundaries these storms left behind will focus the new storms. Lacking much model agreement, have just worked chc pops from the NW to the S through the day. Although west winds will mix a little bit frier air down, the wave aloft should provide some cooling and height falls to allow the potential for severe storms again. However, not all the storms will be severe, and the main threat will be damaging winds again, along with frequent lightning. It will still be very warm and humid, but not as oppressive as Friday, with highs more typically summer like, in the mid 80s to around 90, and TDs in the 60s.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... Any showers/storms will wind down early this evening as the wave moves through around 00Z, and skies will clear out. Humidity will drop in the mountains tonight,m but on the coastal plain, as is often the case with light flow, we may be stuck with the low level moisture until the direr air mixes down the morning. Still, it should cools into the low to mid 60s near the coast and 55 to 60 in the mtns and foothills. Sunday should be a fine day with lower humidity, although temps will continue to run a bit above normal, with highs approaching 80 in the mountains and at the beaches, and generally in the 80s elsewhere. Will see a late sea breeze develop, that will be limited to coastal zones. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... High pressure will crest over the region Sunday night before shifting offshore. Looking for mostly clear skies overnight with lows from the mid 50s to lower 60s. Cold front approaches from the west on Monday bringing increasing clouds and afternoon showers and thunderstorms. Some moderate unidirectional shear coming along with the associated shortwave which may produce a few severe cells with wind damage being the main threat. Very warm and humid airmass will be in place ahead of this system with daytime highs ranging through the 80s north and upper 80s to mid 90s south. Showers and thunderstorms will gradually taper off and skies will clear after midnight Monday night as the front pushes east of the region. lows will range from the lower 60s north to the lower 70s south. High pressure building in from the west will bring slightly cooler and less humid air into the region on northwest winds Tuesday. Expect mostly sunny skies with highs in the mid 70s to lower 80s north and mid to upper 80s south. Tuesday night will feature mostly clear skies as high pressure crests over the region late. Lows will generally range through the 60s. High pressure will shift offshore on Wednesday as a weak cold front approaches from the northwest. Bulk of the day should be mostly sunny with highs once again ranging through the 80s. Weak frontal boundary will slowly sag south into the region Wednesday night and will stall over the region by Thursday morning. This boundary will be the focus of showers and thunderstorms on Thursday. Expect shear to be marginal at best and forcing along the frontal boundary minimal so will likely see pulse type storms during the afternoon. Highs on Thursday will range through the 80s to near 90. Showers and thunderstorms should quickly die out with loss of heating on Thursday evening. Frontal boundary will remain draped across southern zones on Friday which will likely lead to another round of showers and thunderstorms in far southern New Hampshire and possibly coastal Maine. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... Short Term...May see a short period of valley fog at KHIE/KLEB this morning, but otherwise VFR expected today. Once again scattered TSRA could produce strong wind gusts and tempo flight restrictions, mainly this afternoon. Tonight and Sunday will be mainly VFR with the exception of valley fog. Long Term...VFR Sunday night. VFR on Monday with areas of MVFR ceilings and vsby in Showers and thunderstorms. VFR Tuesday and Wednesday. && .MARINE... Short Term...Still some reports of seas at 5 feet, but this should subside by 12z, if not sooner. Otherwise seas and winds remain below SCA levels through Sunday. Long Term...No problems noted. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM...Curtis SHORT TERM... LONG TERM... AVIATION...Arnott MARINE...

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