Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
499 FXUS61 KGYX 071032 AFDGYX Area Forecast Discussion National Weather Service Gray ME 632 AM EDT Mon Sep 7 2026 .WHAT HAS CHANGED... Minor changes to reflect latest observational trends. Tweaked the aviation discussion for the 12Z TAF package. && .KEY MESSAGES... 1. Mostly dry conditions with warmer temperatures today and Tuesday. 2. A seasonably strong low pressure system will drag a cold front across the area late Wednesday into Thursday. Thunderstorms will be possible ahead of the cold front late Wednesday, and showers Wednesday night along the front. A period of gusty winds will be possible on Thursday. && .DISCUSSION... KEY MESSAGE 1 DESCRIPTION... Upper low near Nova Scotia finally loosens its grip on the region and exits into the northern Atlantic. A NW gradient will remain over the area with winds gusting 20-25 mph from late morning into the afternoon. Rising heights and warmer air 850 mb will bring highs into the mid to upper 70s with low 80s near the coast thanks to downsloping NW winds. A cold front will sag into the area Monday night into Tuesday morning bringing slight chances for a shower while much of the area will remain mostly dry. Broad high pressure along the East Coast will promote fair weather Tuesday with highs mainly in the 70s. KEY MESSAGE 2 DESCRIPTION... Models remain in good agreement that strengthening area of low pressure will track over James Bay into northern Quebec late Wednesday through Thursday. The leading warm front will bring increasing clouds Wednesday and possibly some showers Wednesday afternoon. Low level winds will ramp up Wednesday evening with a corridor of 40-50 kt SW winds at 900 mb translating across southern NH and the coast around midnight Wednesday night. Soundings continue to look stable near the coast while there may be a brief period where winds could gust in excess of 30 mph across southern NH. Deep moisture will advect into the region through Wednesday night ahead of the trailing cold front. The timing of the frontal passage will occur overnight and therefore limit instability for storms. Thunderstorms that form upstream may reach portions of the CT Valley through northern NH before instability completely wanes with thunder chances diminishing south of the mountains. Widespread showers look likely across much of the area late Wednesday night while overall rainfall amounts will be around 0.25 inches outside of any convection. There will be a drying trend Thursday morning as winds shift westerly. A secondary cold front will cross Thursday afternoon bringing renewed rain chances. Strong winds aloft will remain present over the area Thursday with some soundings showing mixing to 850 mb. This may allow for widespread gusts approaching 30 mph and some spots approaching 40 mph. The secondary front will usher in a cooler air mass by Friday with high pressure moving overhead Friday night. This will favor radiational cooling that could bring northern valleys into the 30s for lows Friday night. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... Through 12Z Tuesday...Mainly VFR through this morning except at LEB and HIE where valley FG will continue to bring IFR-LIFR restrictions through around 13Z. VFR prevails today with gusts again up to 20 kt from the NW. VFR likely tonight except for valley fog at LEB and HIE. Outlook: Tuesday: VFR conditions expected. Wednesday: Local MVFR or lower conditions possible in showers and thunderstorms, especially overnight. LLWS possible near the coast. Thursday: Becoming VFR. West wind gusts at or above 25 kt possible. Friday-Saturday: VFR conditions expected. && .MARINE... Winds and seas remain below SCA thresholds today through Tuesday as high pressure remains in control. Winds will generally remain westerly shifting SW at times. Southerly winds will increase Wednesday as low pressure tracks into Quebec with gusts approaching 25 kts by Wednesday evening. Winds continue to strengthen Wednesday night as they shift SW with SCA conditions likely for all waters. Seas are expected to build above 5 ft, especially northeast of Jeffreys Ledge, with some 7 ft seas southeast of MISM1. SW winds will come down from their peak Thursday while SCA conditions persist. Winds and seas will fall below SCA thresholds Thursday night with high pressure building in late week. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ DISCUSSION...Tubbs/Schroeter AVIATION...Tubbs