Area Forecast Discussion
Issued by NWS Caribou, ME

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000 FXUS61 KCAR 172113 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 413 PM EST Thu Jan 17 2019 .SYNOPSIS... Weak low pressure moves across the region Friday, followed by an Arctic cold front Friday night and Arctic high pressure on Saturday. A Noreaster is expected to approach from the southwest Sunday and move through the Gulf of Maine Sunday evening. && .NEAR TERM /THROUGH FRIDAY/... High pressure ovr the CWA as of 20z this afternoon with next lopres system in the OH Vly. This system wl spread east overnight with light snow mvg into the far swrn areas around daybreak. All guidance showing light snow on the order of 1-2 inches, though hires models are hinting at a band dvlpng ovr the ern border in the aftn with potential for advisory levels. However, feel this banding could be covered with a short-fused SPS so as not to distract from the more significant storm on Sunday. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... The last of the snow will move out Friday evening with up to an inch in Washington County and along the eastern border. The Arctic front follows and there could be snow squall with the front. The snow squall parameter is flashing some decent signals in northern Aroostook County during Friday evening. Behind the Arctic front, temperatures and wind chills will plummet and a Wind Chill Advisory has been issued starting 1 am EST Friday night into Saturday afternoon for the northern half of the forecast area. H925 temps on Saturday will drop as low as -30C towards the Saint John Valley. These temps will translate into the season`s first subzero high temperatures on Saturday...at least in most of Aroostook County. Temperatures will be a bit higher further south with low to mid teens along the coast. Winds will die off in the afternoon into the evening with a very brief window of radiational cooling before high clouds thicken and lower ahead of the storm. A massive area of low pressure will track out of the Ohio River valley towards the New England coast by Sunday morning. This developing Nor`easter will bring an impressive swath of southern stream moisture northward...overrunning the bitterly cold Arctic air mass. Used a multi-model ensemble mean for temps Saturday night into Sunday night. The very cold low level wedge of air will remain in place all the way to the coast with unusually cold temperatures to go with moderate to heavy snow. Current forecast wind chills on Sunday meet advisory criteria in northern zones...something that is difficult to recall in the past decade. Our current storm track takes the deepening low across the Gulf of Maine towards the southern side of the Bay of Fundy. It will follow an intense coastal front that will set up early Sunday. This coastal front will feature an H925 thermal gradient of over 30C within 100 miles. This coastal front and higher PW values will ensure the heaviest storm QPF is near the coast and manage to produce enough warm air aloft to create mixed precip for coastal Hancock and Washington counties. This will be in the form of sleet for the most part and could accumulate some 1 to 3 inches on top of a foot of snow. Intense banding with greater than 2 inch an hour snowfall rates are likely late Sunday night through the day Sunday. Overall totals could reach around 20 inches towards Bangor...tapering towards a foot in far northwestern Aroostook County. Snow ratios start on the high side, with a deep profile in the DGZ, but will be reduced by both increasing winds, and in the southern half of the area, the warm nose aloft. In terms of P-type, blended upper level thermal profiles from the 12Z NAM and GFS for the coastal sleet. While a Winter Storm Watch has now been issued, we will have to give serious consideration to a blizzard with winds and snowfall rates in the ballpark. Regardless, blowing and drifting snow with potential whiteout conditions will be a tremendous problem impacting travel Sunday into Monday. Travel late Saturday night through Sunday night should be avoided and that message cannot be stressed enough. Overall snowfall totals in this forecast area will probably be heavier than areas to the south and east as the sfc low really strengthens later Sunday as the southern and northern branches phase and a trowal extends significant snowfall into Sunday night. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... On Sunday night, the northern and southern streams fully phase and an upper level cut-off low forms while the surface low continues to deepen in the Canadian Maritimes. This means the snow continues in the forecast area with pops slowly decreasing by Monday morning. Most of the snow will fall before midnight, but north winds will continue increasing as the storm deepens. Any consideration of a blizzard headline will have to be extended into Sunday evening as snowfall rates could still be formidable in eastern Aroostook County with the trowal. Wind gusts to 40 mph through the night will continue to make travel extremely hazardous due to blowing and drifting snow. Furthermore, wind chills will remain well below zero through the night and into Monday. Snow continues to wrap around the closed system into the area through Monday until the upper low exits east by Monday evening. High pressure and lighter winds arrive Tuesday. Tuesday night into Thursday, a warm advection event is expected to generate snow that will generate mixed precip by Wednesday night. Cooler and drier weather returns Thursday into Friday. There is still a lot of uncertainty involving the mid- week system into terms of timing as well as phasing between the northern and southern streams. && .AVIATION /20Z THURSDAY THROUGH TUESDAY/... NEAR TERM: VFR conditions expected until closer to 12z Fri as low MVFR cigs move in ahead of next light snow event. Expect that IFR snow will likely occur after this time for all but FVE terminals thru end of TAF valid time. SHORT TERM: On Friday night, expect tempo IFR to LIFR in showers during the evening...followed by VFR for all sites. VFR continues through Saturday evening. Later Saturday night, all sites decrease to LIFR to VLIFR in heavy snow through the day on Sunday and into Sunday night. Conditions improve to IFR on Monday and VFR returns Monday night into Tuesday...outside of occasional MVFR cigs north of GNR and HUL. && .MARINE... NEAR TERM: Winds will come up ahead of the system tomorrow morning with marginal SCA levels expected in the morning. SHORT TERM: A Small Craft Advisory has been issued for Friday night into Saturday morning. An advisory for freezing spray may be needed Saturday morning. A gale...and quite possibly...a storm will be needed Sunday into Monday night with a Nor`easter. && .TIDES/COASTAL FLOODING... An intense coastal storm is expected to move through the Gulf of Maine on Sunday generating a storm surge of 2-3 feet along the Eastern Maine Coast. In addition to this the astronomical tide is expected to be close to the highest levels of the month during the Sunday Morning high tide cycle between 9:15 and 9:45 AM. Even though the highest storm surge is not expected until later in the afternoon, tide levels are expected to be high enough near the time of high tide to result in possible minor coastal flooding. Even though the largest waves are not expected until late afternoon, building wave heights along the coast in the morning may also produce overtopping, splash over, and beach erosion. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Winter Storm Watch from late Saturday night through Monday morning for MEZ001>006-010-011-015>017-029>032. Wind Chill Advisory from 1 AM to 2 PM EST Saturday for MEZ001>006-010. MARINE...Small Craft Advisory from 9 PM Friday to 11 AM EST Saturday for ANZ050>052. && $$ Near Term...Farrar Short Term...MCW Long Term...MCW Aviation...Farrar/MCW Marine...Farrar/MCW Tides/Coastal Flooding...Mignone

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