


Area Forecast Discussion
Issued by NWS Caribou, ME
Issued by NWS Caribou, ME
968 FXUS61 KCAR 021130 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 730 AM EDT Tue Sep 2 2025 .SYNOPSIS... High pressure will remain over the area today through Wednesday then move east of the region on Thursday. An occluded front will cross the area Friday followed by a cold front on Saturday. && .NEAR TERM /THROUGH WEDNESDAY/... 7:30 AM Update...Updated cloud cover to match satellite, and updated temperatures to reflect observations. See below for updated Aviation section. Previous Discussion... Some mid-and-upper level clouds associated with a shortwave trough to the south will continue to work their way into the area early this morning but there should be enough clearing for strong radiational cooling, leading to some patchy valley fog particularly in northern Maine. Decreased temperatures slightly from the NBM over the north as it tends to run too warm in these situations. An upper-level trough moving northeast across New England will result in some clouds overhead today but otherwise expect dry conditions with highs around 80. Mostly clear skies tonight will again likely lead to some patchy fog in the river valleys. By Wednesday, the trough will have moved into Maine bringing a chance for afternoon showers and thunderstorms, primarily north and west of the line between Greenville and Houlton. Not currently expecting a severe threat as deep-layer shear is weak but the strongest storms will likely be in the far northwest where CAMs show instability up to about 1200 J/kg, decreasing quickly further south. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... High pressure will remain over the area Wednesday night bringing a mostly clear and moonlit night. The clear sky and calm air may allow patchy valley fog to form late at night. High pressure will begin to slide to the east on Thursday. This will allow a light southerly return flow to set in behind the high. The warm air advecting in from the south combined with upper level ridging will bring highs at near mid-summer norms in the upper 70s to near 80 under a mostly sunny sky. The southerly return flow breeze will continue Thursday night under a moonlit sky. The breeze will prevent much cooling with lows only expected to be in the low to mid 50s. Our attention at the end of the week turns to a large low pressure system tracking east through central Ontario. We will be on the southeastern fringe of this system. An occluded front out ahead of this low will approach and cross the area Friday. There will be some moisture with this front, mainly across the northern part of our area on north. However, upper dynamics and low level convergence are weak. Therefore, we will likely just get a broken band of showers, mainly north, giving around a tenth to a quarter inch of rain. The occlusion will rotate northeast and away from the area Friday evening. && .LONG TERM /FRIDAY THROUGH MONDAY/... As the first occlusion lifts away Friday night, another spoke of energy, now in the form of a cold front, will approach late Friday night into Saturday. This has the potential to bring another line of showers through late at night or Saturday morning. However, moisture seems limited and although we will be under strong southwesterly flow aloft on the southeastern edge of the Canadian low, we will lack strong dynamics to squeeze out much moisture so again only a broken line of showers is expected. The big Canadian upper trough will continue to migrate east into Quebec on Saturday. A new upper level wave circulating to the south of the low around the base of the trough will approach on Saturday possibly bringing a band of significant rain to the region later Saturday into Saturday evening. Both the ECMWF and the GFS are now offering the potential for significant rain from this disturbance with up to an inch possible over parts of the area. However, the band of rain is projected to be narrow, and this far out it could still miss us to the north or the south so confidence is limited since this is way out on day five. Sunday into early next week will then be cooler as chilly air circulates into the area around the upper low. The low heights and residual moisture will continue to bring chances for spotty showers, mainly across the north. Highs going into early next week will be primarily in the 60s. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... NEAR TERM: VFR during the day today. Fog lingers at northern terminals, predominantly KFVE. Kept fog in the TAFs until sun burns it off this morning. Possible patchy fog tonight, but otherwise generally VFR. MVFR possible at FVE/CAR/PQI terminals Wednesday in scattered showers and thunderstorms. Light and variable winds this morning, becoming S around 5kts after daybreak today. Winds go light and variable tonight, before becoming SW around 5 to 10 kts Wednesday. SHORT TERM: Wednesday night...VFR with the possible exception of valley fog inland late. Light and variable wind. Thursday...VFR. Light S wind. Thursday night...VFR, possibly lowering to MVFR or IFR south in lower stratus late at night. Friday...MVFR to IFR early, becoming VFR. South wind. Friday night...VFR lowering to MVFR. South wind. Saturday...MVFR to possibly IFR. SW wind. && .MARINE... NEAR TERM: Winds and seas below Small Craft criteria through Wednesday. Seas generally 3 ft or below over all waters. Light SSW wind today, becoming SW at 5 to 10 kts tomorrow. Some patchy fog possible this evening and overnight. SHORT TERM: A few gusts may reach 25 kt out of the south Friday night and seas may build up to 5 ft in response to the southerly. Otherwise, wind and seas should be below SCA for the rest of this week into the coming weekend. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...Brennan/Melanson Short Term...Bloomer Long Term...Bloomer Aviation...Brennan/Melanson/Bloomer Marine...Brennan/Melanson/Bloomer