Area Forecast Discussion
Issued by NWS Caribou, ME
Issued by NWS Caribou, ME
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024 FXUS61 KCAR 070946 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 546 AM EDT Fri Jun 7 2024 .SYNOPSIS... An upper level trough of low pressure will slowly approach today...cross the area this weekend...then continue northeast into the Maritimes on Monday. High pressure will build into the area Tuesday. && .NEAR TERM /THROUGH TONIGHT/... 543 am update...Added areas of dense for to coastal Downeast and issued a Special Weather Statement for the fog. Previous discussion... An occlusion will make very slow progress eastward into the area today as a blocking high gradually retreats into the Maritimes. The area remains in a col between two large scale cut-off lows within the omega block. The occlusion is weakening, but it is moving so slowly that rainfall may accumulate to over one half inch in areas of Piscataquis County, northern Somerset County, and far northwestern Aroostook County. In contrast, the block holds for eastern Aroostook County where dry conditions will prevail today and highs will be some 10 to 15 degrees warmer than where the showers linger all day in Piscataquis County. Not really seeing any compelling reason to mention thunderstorms today with the lack of surface heating or elevated instability. That changes later tonight. The other significant aspect to area weather today will be the dense low level moisture and onshore flow ahead of the occlusion. That is producing fog and drizzle towards the coast. The coast will be shrouded in low clouds and fog all day. The persistent low clouds under the frontal inversion will extend northward to Bangor, Millinocket and Greenville throughout the day with corresponding reductions to high temps. For tonight, the occlusion remains parked over the area and the low clouds/fog will thicken and move northward again. However, dynamic changes aloft will reinvigorate the occlusion. The upper low in the Great Lakes digs steadily towards New England during the night. By late in the night, a strong vort max will rotate around the base of the upper low into the area. This strong lift and cooling aloft should result in heavier showers and thunderstorm activity after midnight across the area. The frontal inversion remains in place, so no severe thunderstorms are anticipated but elevated CAPE is expected along with good deep layer shear as the LFQ of a strong upper jet moves into the area. Have increased and expanded PoPs and QPF over the CWA after midnight. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... Upper level low pressure will be nearby to our west Saturday morning while a surface occlusion extends east from this low to surface low pressure over our region. Showers Saturday morning will be most concentrated over central parts of the region supported by surface convergence from the occlusion. From there, the showers will lift north during the day as the triple point low slowly lifts north. Cold air pooled aloft in the upper low will work with just a bit of daylight heating to produce thin CAPEs of around 200 J/KG up to 25K ft over central and northern parts of the area. Will keep a slight chance for thunder central and north on Saturday. The initial band of showers concentrated with the surface occlusion will lift north and east of the area Saturday night. However, moisture pooled in the upper low and some trailing weak disturbances in the upper trough will continue to produce showers and some drizzle overnight Saturday night, mostly across the northern half of the region. The upper low and surface trough will be draped across far northern reaches of our region on Sunday resulting in wrap around showers and drizzle continuing over the north. The surface convergence and cool air aloft may again result in a chance for isolated thunderstorms although soundings are not advertising as much instability Sunday, only around 50 J/kg of CAPE, then they are for Saturday. Downeast will chance have a chance for showers with some breaks of sunshine possible further south of the low centers. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Low pressure, both surface and aloft, will be lifting away to the northeast into the northern Maritimes on Monday. Hang back troughiness and moisture pooled in the trough will continue to result in low cloudiness and some showers scattered across the north. There is just a bit of CAPE, around 50 J/KG, and a weak trailing cold front approaching the region. This may result in some isolated thunderstorms again on Monday, mainly north. Low pressure surface and aloft will continue to weaken and move up and away to the northeast on Tuesday. The trailing troughiness will finally slide off to the east as high pressure and upper ridging build in from the west. This will bring partial sunshine with inland highs in the mid 70s. Looking ahead to Wednesday, surface high pressure and upper level ridging should remain over the area bringing a warm day with some sunshine. Meanwhile, a new trough will begin to approach from the west. The GFS is lifting some showers into southern parts of our area late in the day Wednesday while other models are much weaker with the approach of any showers. The uncertainty seems to be in the interplay between a northern branch and southern branch shortwave with the ECMWF keeping the southern feature south while the GFS lifts the southern wave up the coast. && .AVIATION /10Z FRIDAY THROUGH TUESDAY/... NEAR TERM: LIFR conditions will prevail today for GNR, BGR and BHB and could be VLIFR at times early this morning and again tonight. IFR cigs will affect MLT and HUL this morning, but cigs may lift to MVFR this afternoon. Further north towards PQI and CAR, a period of MVFR cigs are expected this morning, but VFR conditions return for the afternoon. All sites will become IFR or worse tonight. Embedded thunderstorms are a threat all sites after midnight. SHORT TERM: Saturday...IFR north, IFR to MVFR south. Light SW wind south and light NE wind over the north. Saturday night...IFR north. IFR To MVFR south. SW wind. Sunday...IFR north and MVFR south. Light W wind. Sunday night...IFR to MVFR north. MVFR to VFR south. Light W wind. Monday...MVFR north. VFR to occasionally MVFR south. NW wind. Monday night...MVFR to VFR north. VFR south. Light NW wind. Tuesday...VFR. Light NW wind. && .MARINE... NEAR TERM: Fog will be the dominant feature through the period. Cannot rule out thunderstorms late tonight. Seas will slowly increase today as south swell increases towards 4 to 5 feet. East winds will slowly become southeasterly by later today. Gusts around 15 kt can be expected today, but decreasing later today into tonight. Reduced guidance winds due to strong stability. SHORT TERM: Wind and seas are expected to remain below SCA this weekend through early next week. Moderately humid air over the colder waters will likely result in some fog and mist over the weekend into early next week. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...MCW Short Term...Bloomer Long Term...Bloomer Aviation...MCW/Bloomer Marine...MCW/Bloomer