022 FXUS61 KCAR 170657 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 157 AM EST Tue Dec 17 2019 .SYNOPSIS... High pressure will build toward the region through overnight. A weak area of low pressure is expected to move east of the southern New England coast on Tuesday and then move east Tuesday night. Another weak area of low pressure is expected to track across Downeast Maine late Wednesday and then move east Wednesday night and Thursday. High pressure will build back in for Friday. && .NEAR TERM /THROUGH TUESDAY/... 120 AM Update: Some clouds are showing up across the northern and western sections per the latest satl imagery. Most of this cloudiness was mid level based(5000-8000 ft). Further s, high clouds were streaming in from the sw w/most of this being thin. Winds have stayed up some across the northern 1/2 of the CWA keeping temps up some. Expecting the winds to drop off by daybreak. For the rest of the CWA, light winds prevail. Hrly temps were adjusted to meet the latest obs. Overnight mins attm look fine. See marine section below. Previous discussion: High pressure and clear skies tonight present an opportunity for strong radiational cooling, but expect winds to prevent much decoupling of the boundary layer. Have leaned towards lower bias-corrected guidance. High clouds will increase in southern zones later tonight and also mitigate radiational cooling. These clouds will originate from a fast-moving southern stream open wave. The surface low will deepen as it moves off the Atlantic coast on Tuesday, but the low will remain well south of the area as it tracks south of Cape Cod and well south of Nova Scotia. The northern edge of the precipitation shield will arrive along the coast towards mid-afternoon and likely arrive in Bangor by late afternoon. Total snowfall amounts by evening are expected to remain a little over an inch or less. No snow at all is expected north of a Greenville to Danforth line by Tuesday evening, but high clouds will thicken and lower for the entire forecast area during the afternoon. Warm advection will push tomorrow's highs to upper 20s to lower 30s for much of the area with light winds. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... Snow likely to continue into Tuesday evening for far southwestern portions of the forecast area, mainly from about Bangor and Machias southwest. Storm total accumulations of just an inch or two. As the system exits, some hints of a weak inverted trough/norlun feature mainly west of Penobscot Bay and in Gray's forecast area. Something to keep an eye on. Much stronger inverted trough/norlun feature possible Wednesday night after a quiet day Wednesday. Powerful mid/upper level low will be diving southeast through Vermont, New Hampshire, and SW Maine. As this happens, NW/SE aligned low level inverted trough sets up. This inverted trough will likely be the focus of some locally heavy snow with high snow ratios/high fluff factor. However, the location of the inverted trough/norlun is notoriously difficult to pinpoint until within 12 hours. Convection allowing models likely will resolve the feature better as time gets close. Right now think the best shot is from Penobscot Bay region NW. Did raise PoPs to likely for far west/southwest edge of forecast area, from about Bar Harbor NW to Bangor and NW to Greenville. Potential is there for local amounts of over 6 inches, but expect a significant difference in snow amounts over short distances and low forecast confidence until the time gets close. Very cold air Thursday and breezy as the upper level pushes east of us with cold advection. Can't rule out a few snow showers mainly over the north, but typically looking dry. Highs only in the teens. Airmass Thursday looks perhaps a touch colder than today's. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... High pressure slowly builds in Thursday night through Friday night, becoming centered over the area around Saturday. High confidence in dry conditions and below average temperatures through Saturday. Forecast confidence decreases Sunday into early next week, specifically regarding potential interaction of the northern and southern jet streams. Most models keep the northern stream more dominant with perhaps a few weak systems in westerly flow Sunday to Tuesday. However, a few models bring the southern jet stream close to the area with potentially an upper low over the Southeast approaching our region from the SW, which could lead to more active weather. For now, favored the former solution of the northern stream dominating with weak systems. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... NEAR TERM: VFR conditions are forecast through Tuesday except towards BGR, Machias and BHB where IFR vis in snow is possible by mid- afternoon into Tuesday evening. LLWS is possible tonight with around 40 kts near 2k ft, but light surface winds. SHORT TERM: Tuesday Night...Potential MVFR/IFR in snow KBGR and KBHB, otherwise mainly VFR. Fairly light winds. Wednesday...Generally VFR with light winds. Wednesday Night...Generally VFR except potential for IFR/MVFR with snow possible KBHB/KBGR/KGNR. Thursday through Friday...Mainly VFR but windy. Saturday...Lighter winds and VFR. && .MARINE... NEAR TERM: Update...Small Craft Advisory from Eastport to Schoodic Point has expired. Sustained winds have dropped below 20 kts w/gusts around 22 kts and will continue to drop off overnight. The wind and seas will be below SCA levels on all of the waters Tue. SHORT TERM: Small craft winds/seas likely Tuesday night. Winds diminish Wednesday and Wednesday night, but seas remain up around 5 feet. Possibility for gales Thursday and Thursday night with cold offshore flow. Although seas surface temperatures are still fairly mild in the mid to upper 40s, can't rule out some freezing spray. Winds and seas gradually subside Friday through Saturday as high pressure builds in. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...Hewitt