Area Forecast Discussion
Issued by NWS Caribou, ME
Issued by NWS Caribou, ME
933 FXUS61 KCAR 210929 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 529 AM EDT Mon Sep 21 2026 .WHAT HAS CHANGED... 530 am update...Update for 12z aviation discussion. && .KEY MESSAGES... 1) Potential for patchy frost Monday, Tuesday, and Wednesday nights across the north. 2) A coastal low could impact at least Downeast Maine late this week. && .DISCUSSION... KEY MESSAGE 1...Potential for patchy frost Monday, Tuesday, and Wednesday nights across the north. KEY MESSAGE 1 DESCRIPTION... A cold front currently draped along the St. Lawrence will continue to drop south today. 1029mb sfc high located over Ontario will build south into the area tonight with skies clearing over the north. As high builds in may see deeper valleys decouple acrs the northwest resulting almost ideal radn/l cooling conditions. Only caveat will be some semblance of a pressure gradient may still exist leading to ocnl spurts of wind. The growing season has climatologically ended for areas north of Bangor as of this morning (Monday morning), though those who still have tender vegetation should take steps to protect them tonight. High pressure will be ridged across the region Tuesday and Wednesday nights with clear skies and light winds. This will provide favorable conditions for radiational cooling. Patchy/areas of frost are expected Tuesday and Wednesday nights across northern and central portions of the region. Temperatures could fall below freezing across the normally colder northern low lying and valley locations. KEY MESSAGE 2...A coastal low could impact at least Downeast Maine late this week. KEY MESSAGE 2 DESCRIPTION... A coastal low will develop offshore from the Mid-Atlantic region mid week. At the same time, high pressure will remain centered northwest of the region. The track of the ocean low through late week is still uncertain. With blocking high pressure to the northwest, uncertainty still exists regarding the northern edge of the precipitation shield and whether rain will reach the forecast area. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... Today...VFR at Downeast terminals, though may see brief MVFR cigs at BHB the first hour or two. MVFR with improvement to VFR northern Aroostook terminals by 18z this afternoon. NW winds 5-10kts, with gusts to 20kts. Tonight-Tuesday night...Mainly VFR, though may see variable conditions in patchy fog each morning. NNW around 5kts. Wednesday-Thursday night...Variable conditions in any patchy late night fog. Otherwise, VFR. North/northeast winds 5 to 10 knots. Friday...VFR north. VFR/MVFR Downeast with a chance of rain. Across northern areas, northeast/north winds 5 to 10 knots. Across Downeast areas, northeast/north winds 10 to 15 knots with gusts up to around 20 knots. && .MARINE... NNE winds today will remain under 25kts all waters, increasing above 25kts over waters 25-60NM tonight before diminishing Tue morning. Seas remain below small craft advisory levels over all waters through Tuesday. Small craft advisory level wind gusts possible Wednesday. Building seas late week. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ DISCUSSION...21/JMM AVIATION...21/JMM