Area Forecast Discussion
Issued by NWS Caribou, ME

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000 FXUS61 KCAR 312250 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 650 PM EDT Tue Mar 31 2020 .SYNOPSIS... An upper level low will remain across the region through Thursday. Intensifying low pressure will track south of the Gulf of Maine Wednesday night through Thursday. High pressure will build across the region later Friday into Sunday. && .NEAR TERM /THROUGH WEDNESDAY/... No sig chgs made to the fcst this update. Fcst hrly temps/dwpts were updated into the ovrngt using past obsvd aftn hi temps and latest sfc obs trends with chgs to fcst ovrngt lows attm. Prev Disc: An upper level low will remain across the region tonight through Wednesday while a disturbance rotating around the upper low moves west across the forecast area. Clouds in advance of the disturbance are moving across eastern portions of the forecast area and will advect across the remainder of the forecast area early tonight. Isolated to scattered snow showers will expand westward across the forecast area overnight with the upper level disturbance, with the better chances across northern and eastern areas. Any snow accumulations across northern portions of the forecast area overnight are generally expected to be less than an inch. The disturbance will cross the region Wednesday. Across northern areas, morning snow showers will mix with rain showers during the afternoon. Additional snow accumulations of up to around an inch are possible across northern areas Wednesday. Across Downeast areas, morning snow/rain showers will transition to rain showers during the afternoon. Low temperatures tonight will range from the mid to upper 20s north, to the upper 20s to around 30 Downeast. High temperatures Wednesday will range from the mid to upper 30s north, to the lower 40s Downeast. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... Strong blocking pattern continues with a powerful North Atlantic high that will slowly retrograde into northeastern Canada by the end of the period. Low pressure currently organizing in North Carolina will rapidly deepen in the open Atlantic Wednesday into Wednesday night and track northeastward south and east of the 40/70 benchmark. A warm front will propagate westward from New Brunswick in the easterly flow with steady rain breaking out later Wednesday night and continuing much of Thursday, and into Thursday night towards the coast. Overall, the low is tracking a bit further north than advertised in yesterday`s guidance and is stronger. Therefore, QPF towards the coast has increased to three-quarters of an inch and it`s possible up to an inch could fall by later Thursday night. Precip will be in the form of rain. A strong easterly LLJ is still indicated. With current forecast temps/dew points/QPF, am not anticipating ice movement on northern rivers, but increases in any of these parameters will increase risk. There will be significant snowmelt in the northern zones. The blocking high presses south later Thursday as the low slowly wobbles back to the south. Drier and less humid air will slowly work southward Thursday night into Friday. Clouds remain Friday with plenty of 850mb moisture, but winds will be the big concern with the tight pressure gradient between the departing low and the high to the north. Gusts to 35 mph are possible from the northeast. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... The big blocking high over eastern Canada will continue to be the dominant feature through the period. Light winds, sunny skies and above normal temperatures can be anticipated for the weekend. Low dew points in the teens and 20s and nighttime temps in the 20s will ensure snow melt is well controlled. Continued to adjust dew points down below guidance through the weekend. Guidance continues to vary dramatically on whether a frontal system can successfully navigate through the blocking ridge Sunday night into Monday. The GFS has been consistent in washing out the front while GEM/ECMWF effects continue to vary with each run. Tended to favor GFS, but still left in chance PoPs Sunday night and slight chance PoPs in the north on Monday. There`s not much cold air in place so mostly rainshower activity is indicated. The blocking ridge remains into early next week, but will gradually break down by mid week. Above normal temperatures are expected through the long term, but low dew points will likely continue with dry Canadian air mass. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: VFR conditions are expected across the region early tonight. Conditions will then lower to MVFR/IFR levels across northern areas overnight, with MVFR conditions developing Downeast. Snow showers will develop across the region overnight, with the better chances across northern and eastern areas. IFR/LIFR conditions are expected across northern areas Wednesday, with MVFR/IFR conditions Downeast. Across northern areas, morning snow showers Wednesday will mix with rain showers during the afternoon. Across Downeast areas, morning snow/rain showers will transition to rain showers during the afternoon. SHORT TERM: Wednesday night into Thursday night...Predominately IFR cigs with tempo IFR vis in rain/drizzle. LLWS likely especially towards BGR and BHB. Friday into early Saturday morning...MVFR cigs. Gusty NE winds up to 30 kt. Saturday into Sunday...Becoming predominately VFR. && .MARINE... NEAR TERM: A Small Craft Advisory remains in effect for all the waters tonight. Small craft advisory conditions could then persist on much of the waters, with the exception of the intracoastal waters, Wednesday. Visibilities will be reduced in scattered rain/snow showers Wednesday. SHORT TERM: SCA conditions Wednesday night will increase to gale conditions on Thursday. The gale will continue into Friday night. A few gusts to storm strength are possible Thursday night. Seas will build towards 13 feet Friday. Two wave groups are expected during the gale, a steep NE wind-driven wave and a long period SE swell that will be approaching the 13 feet. After the gale ends, SCA conditions persist into Saturday morning. && .TIDES/COASTAL FLOODING... Looking at ETSS with the NE winds for Friday morning`s high tide, a surge of up to two feet is possible. Relatively low astronomical tides reduce the risk of coastal flooding. Can`t rule out some minor splashover with the Friday AM high tide at usually vulnerable spots such as Seawall Rd. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Small Craft Advisory until 8 AM EDT Wednesday for ANZ050-051. && $$ Near Term...VJN Short Term...MCW Long Term...MCW Aviation...VJN/MCW Marine...VJN/MCW Tides/Coastal Flooding...MW is the U.S. government's official web portal to all federal, state and local government web resources and services.