Area Forecast Discussion
Issued by NWS Caribou, ME
Issued by NWS Caribou, ME
253 FXUS61 KCAR 220013 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 813 PM EDT Mon Sep 21 2026 .WHAT HAS CHANGED... - Updated aviation discussion. && .KEY MESSAGES... 1) Potential for patchy frost tonight, 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 tonight, Tuesday, and Wednesday nights across the north. KEY MESSAGE 1 DESCRIPTION... A strong 1030mb high pressure system located over Ontario builds south into the area tonight, with skies clearing over the north. Anticipating for low lying valleys to decouple across the north, with clear skies, high RH, and generally light winds. Occasional breezy winds could reduce fog chances. High pressure remains over 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 is expected to develop across the Mid-Atlantic region later this week while high pressure remains centered over Quebec. The track of the ocean low is still uncertain with blocking high pressure to the northwest of our forecast area and ridging across the Great Lakes. Uncertainty remains regarding the northern edge of the precipitation shield and whether rain will reach Maine. Northerly to northeasterly winds could become gusty over the weekend, especially along the coast, as a tight pressure gradient forms. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... Tonight...Variable conditions in any patchy fog late. Otherwise, VFR. North/northwest winds around 5 knots. Tuesday...VFR. North/northwest winds 5 to 10 knots. Tuesday night-Thursday night...Variable conditions in any patchy late night fog. Otherwise, VFR. North/northeast winds 5 to 10 knots. Friday-Saturday...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... N winds tonight will remain under 25kts for intra-coastal and outer waters. Waters 25-60NM will see gusts around 25kts tonight, before diminishing Tuesday morning. Seas remain below small craft advisory levels over all waters through Tuesday night. Chance for some patchy overnight fog Tuesday night. Small craft advisory level wind gusts possible Wednesday. Gales possible late week into the weekend. Building seas late week into the weekend. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ DISCUSSION...ASB/JS AVIATION...ASB/JS/CN