Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
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248 FXUS61 KGYX 171926 AFDGYX Area Forecast Discussion National Weather Service Gray ME 326 PM EDT Wed Jul 17 2024 .SYNOPSIS... Heat, humidity, and storms persist into this evening, but a change in pattern will bring relief through late week. A cold front passes this evening and tonight, bringing drier and somewhat cooler conditions for the end of the week into the weekend. High pressure builds in from the west with mostly dry conditions forecast through the weekend. && .NEAR TERM /THROUGH TONIGHT/... Actual sfc front looks to be running from about Quebec City SW to Buffalo at 19Z, and this will shift SE toward the CWA during the afternoon and evening. Convection is breaking out along various boundaries ahead of the front and will continue across the CWA into this evening. Best forcing is currently to our SE as wave is moving NE thru the 500 MB flow tracks from central PA to near KALB by late afternoon, and then weakens. This should help to produce better shear and stronger storms along its path, but it won`t move far enough N at peak strength to contribute to to sever wx across the whole CWA, and thus the SVR watch in place for just the srn half of NH this afternoon. I think the current cluster of storms over the lower Hudson valley are the ones we have to watch. There are some weaker TSRA from SW NH into the ME mtns this afternoon, but otherwise it`ll stay mostly to partly sunny until the storms move in. It`ll also stay hot and humid until the storms arrive as well. Convection will wind down from the NW zones by around 00Z, and gradually end from NW-SE through the course of the evening, although the sever threat will end by 00Z as well.. Think the actual sfc front crosses too late to see much mixing to the sfc, and we`ll have to deal with one more warm and muggy night, with patchy fog developing once the precip ends. Mins run from the low to mid 60s in the mtns, to around 70 in srn NH and the ME coast. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... Thursday starts off with a lot of clouds, but they should begin to erode during the morning especially away from the coast., where sunshine increases during the afternoon. Along the coast it may take longer to clear completely as secondary move along the front stalled to our S, but should see it become generally clear by mid to late afternoon. In the mtns, Tds will drop off into the mid to upper 50s during the morning, but itll take until mid to late afternoon for that to happen in the S. Highs will be lower than the last few days, but still warm in many spots ranging from around 80 in the mtns to the mid to upper 80s in S NH and on the ME coast, as W winds allow downslope warming. Expecting wide spread clearing Thu night with drier air moving in and much more comfortable sleeping conditions , as mins range from the low to mid 50s in the mtns to around 60 in the the south. Patchy valley fog is also expected. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... A weak cold front will bring a low chance of showers to portions of the region Saturday night into Sunday, but otherwise it looks pretty quiet for Friday into the weekend. The highlight will be drier air in place, making it less humid out, and daytime temperatures won`t be as hot. Highs will be generally in the 80s south of the mountains, although a few southern areas could still reach 90 degrees on Saturday and Sunday. Nighttime will also offer relief with lows primarily in the 50s to lower 60s, and northern valleys may be even be able to dip into the upper 40s on a couple of nights if the skies remain clear and winds stay light. Valley fog will also be possible at night. Going into next week, there may be enough of an increase in moisture for a few showers to develop on Monday, but precip chances increase moreso toward Tuesday and Wednesday of next week as low pressure and a warm front lift toward New England. This is supported by the vast majority of ensemble members from the ECMWF and GFS, but due to this being toward the end of the forecast period and the inherit uncertainty, will not go as high as the NBM on PoPs yet. Temperatures look to remain near or slightly above normal from early to midweek. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... Short Term...Sct TSRA possible this afternoon into early evening, and could cause temp flight restrictions at any terminals, but expecting fog to develop after midnight at KLEB/KHIE/KAUG, and KRKD, which should bring a period of LIFR in the pre-dawn hours. VFR expected Thu and Thu night, except for valley fog at KLEB/KHIE late Thu night. Long Term...High pressure and drier air will bring mostly VFR from Friday through Monday, but there may be some valley fog during the night and early morning hours. A weak frontal boundary may bring a few showers late Saturday night into Sunday, but overall chances for these look low. Enough moisture may be sufficient enough for additional showers Monday afternoon. && .MARINE... Short Term...Winds diminish this evening, and stay below SCA levels through Thu night. Long Term...SCA conditions are currently not expected from Friday through the middle of next week. N/NW winds will be in place across the waters early Friday but will become more S/SW by the afternoon as the seabreeze develops and as high pressure becomes centered SE of the waters. Another weak frontal boundary could cross the waters late Saturday and into Sunday, resulting in another brief wind shift. High pressure looks to maintain control over the waters early next week before a low pressure potentially approaches toward the middle of next week. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Heat Advisory until 6 PM EDT this evening for MEZ012-018>024- 033. NH...Heat Advisory until 6 PM EDT this evening for NHZ004-006- 008>010-012>015. MARINE...None. && $$ NEAR TERM...Cempa SHORT TERM...Cempa LONG TERM...Combs