Area Forecast Discussion
Issued by NWS Caribou, ME

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682 FXUS61 KCAR 091413 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 913 AM EST Fri Dec 9 2016 .SYNOPSIS... An Arctic cold front will move through the region this afternoon. The first Arctic air mass will settle over the area for the weekend. Low pressure will approach Sunday night into Monday with the threat of winter weather. && .NEAR TERM /THROUGH TONIGHT/... Update... Reduced pops today and increased winds later this afternoon into Saturday morning. Wind chills will drop below zero tonight and continue into Saturday morning. Temperatures will start falling this afternoon and continue falling all night due to cold air advection as the Arctic air mass settles over the area. In terms of snow squalls with the Arctic front, most of the risk will be north of Houlton this evening. Guidance is not resolving much of anything with all moisture and instability confined to levels below H850. Used slight chance pops to highlight the risk later this afternoon through the evening. previous discussion Strong cold advection can be expected today as an arctic front crosses the region from the west. The 00z Caribou raob showed 850 temps around -9C with 850 temps expected to fall to around -16C by this evening. Temperatures today are not expected to rise all that much from current readings and then begin to drop off by afternoon with the passage of the boundary. Winds will become northwest at 10 to 20 mph with gusts to 30 mph. Expect mainly cloudy skies across the north today with scattered snow showers expected as the colder air works into the region. Across down east expect partly sunny skies with nothing more than a few flurries. Any snow accumulation across the north today should be less than an inch. The exception will be in any heavier snow bands that set up later this morning where we could see localized accumulations of an inch or two. Liked the way the Canadian Regional was handling things early this morning as its qpf depiction was matching up well with current radar early this morning. Tonight will be partly to mostly cloudy across the north with a lingering snow shower possible this evening, and partly cloudy to mainly clear skies expected across downeast. Low temperatures tonight will be about 10 degrees below normal for this time of year. Expect lows to range from the single digits above zero across the north and around 10 degrees across downeast. Northwest winds at around 10 mph will make it feel even colder. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Sat looks to be the coldest day time hi temps for the season so far with cont`d llvl cold advcn as evident by brisk NW winds and producing wind chills as low as single digits below zero across the N. St Lawrence seaway sn band streamers will conts msly across the N and W, but increased subsidence alf will will keep cld tops low, likely lmtg intensity by this tm, with many lctns between bands likely to experience some sunshine. Kept max PoPs msly in the slgt chc category for now. Ptly cldy skies and sct flurries will likely cont Sat ngt into Sun as wind diminish. With only pockets of mclr skies, the potential for radiational cooling will be lmtd Sat ngt. Temps will remain sig below avg thru these pds. Sun ngt will begin mclr to ptly cldy, then will become cldy from SW to NE across the region late as low pres from the great lks apchs with lgt snfl just reaching wrn ptns of the FA prior by daybreak Mon. Ovrngt lows will be coldest across the N where winds will be lgt and thicker cld cvr last to arrive late Sun ngt. && .LONG TERM /MONDAY THROUGH THURSDAY/... All longer range models are in much better agreement with the tmg and evolution of sn associated with sfc low pres apchg from the great lks. The consensus of these models (supported by ensm data) indicates ovrrng warm advcn snfl slowly spreading newrd thru Cntrl ptns of the region Mon morn and then across the N by Mon aftn. Downeast ptns of the region will likely experience the most snfl from this system from deep layer warm advcn, and even though secondary cyclogenesis occurs alg the Maine coast, enough llvl maritime air will likely result in some mixed rn/sn or even a pd of all rn alg the immediate Downeast coast and outer islands later Mon aftn into eve, somewhat reducing max potential snfl. Across the N, sn will begin lgt Mon aftn but will likely somewhat increase in intensity Mon ngt as a deformation band develops in response to an upper lvl low at arnd 700 mb forming ovr our region. The upshot of all this is that we increased max PoPs to categorical for most of our region with this event with max PoPs occurring across the S durg the day Mon and across the N Mon ngt. Wntr wx advs will be likely for most of the region, with an outside chc of wntr stm wrngs, with lengthy duration of lgt to mdt snfl potentially precluding the issuance of wrngs, assuming models do not waver much from this latest consensus of solutions. Sn should taper to sn shwrs from SW to NE ovrngt Mon into erly Tue morn, followed by a break in the action later Tue into Tue ngt. The next chc of sn shwrs will be Wed into Wed eve ahead of the next arctic front. The 00z dtmnstc model run in particular indicates the possibility of a sfc wv of low pres forming alg the front Wed ngt that could result in more organized snfl spcly for ern ptns of the FA prior to the arctic air arriving to the region by Thu morn, but other models like the ECMWF keep any organized snfl E across the Can Maritimes. For now, we will keep the mention of chc sn shwrs and will wait for later model runs for better consensus. Temps will be milder Tue and thru Wed eve, and then will turn sharply colder late Wed ngt into Thu as what looks to be the next coldest air mass of the season so far enters our FA from QB prov. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... NEAR TERM: Generally VFR conditions expected through tonight. The only exception will be in any localized snow showers that could affect the northern terminals resulting in brief MVFR/IFR conditions at times today. Gusty northwest winds can be expected into tonight. SHORT TERM: Msly VFR across the TAF sites Sat thru Sun with brief MVFR/IFR clgs/vsbys with any sn shwrs across Nrn sites spcly day tm Sat. Clgs/vsbys will then lower from S to N across the TAF sites late Sun ngt thru Mon morn in organized snfl and will cont into Mon ngt...with Downeast sites improving to MVFR late Mon ngt as sn moves NE into Nrn Me. Downeast sites improve to VFR on Tue while Nrn TAf sites improve to MVFR by Tue morn as steady snfl ends as sct sn shwrs. && .MARINE... NEAR TERM: Decided to hold with a strong small craft advisory today and tonight. Do think we will see a few gusts to 35 Kt this afternoon and into early evening as the colder air crosses the water but think we wont see persistent gale conditions. Light freezing spray will be possible late tonight. SHORT TERM: Strong SCA conditions will cont ovr our waters on Sat with cold advcn NW winds and then slowly diminish Sat ngt and Sun morn, with lgt fzg spy ending by Sat aftn. The next chc of hdln conditions will be Mon into Mon ngt with ESE winds ahead of the low pres system apchg from the great lks. Kept close to WW3 wv guidance for fcst wv hts. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Small Craft Advisory until midnight EST Saturday night for ANZ050>052. && $$ Near Term...Duda/MCW Short Term...VJN Long Term...VJN Aviation...Duda/MCW/VJN Marine...Duda/MCW/VJN is the U.S. government's official web portal to all federal, state and local government web resources and services.