Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 142342 AFDGYX Area Forecast Discussion National Weather Service Gray ME 642 PM EST Wed Nov 14 2018 .SYNOPSIS... Arctic high pressure will remain overhead New England tonight, bringing potentially record cold temperatures to the region. The next coastal storm will arrive late Thursday night continuing into Friday bringing snowfall to Maine and New Hampshire. An upper level disturbance will remain over the region Saturday before Canadian high pressure builds into the region Sunday. An Arctic front will cross the region Monday, followed by another weak disturbance midweek. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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640 PM Update...Just a few minor changes to the going forecast based on latest trends in observational and mesoscale model data. Winds will continue to diminish this evening, potentially setting the area up for record low temperatures overnight. Previously... A deep dome of arctic high pres settles over the region tonight allowing winds to diminish and become near calm by later this evening. With clear skies and winds becoming calm, a good 3-6 hour window of radiational cooling expected later tonight. With fresh snow cover the mountains temps should plummet to below zero in many spots. Elsewhere in areas where there is no snow cover, single numbers to lower teens can be expected. This should set some new record low temps for the date.
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&& .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... A sunny start to Thursday but overunning WAA clouds will overspread the area from south to north in the afternoon and thicken by early evening. Models all agree on an initial shot of stg WAA overrunning the deep cold dome over the region. This will allow an initial band of moderate to hvy snow to develop by evening over southern areas of NH and quickly spread north and east into northern NH and all of srn/central ME. Considering the depth of the arctic air mass and very dry air mass allowing substantial evapo cooling, all snow will be forecast with no mixing. A winter storm watch will be issued for these southern areas beginning in the evening with the watch extended to the north over all other areas after midnight. After the initial shot of WAA snow there may be a brief break in the pcpn toward morning until the low-mid level low with its pcpn shield tracks northeast to off the ME/NH coast Thu. Overall going with the record cold temps tonight with most guidance being warmer. Used a blend of model guid for temps Thu/Thu night. If anything temps will tend to be lowered further Thu night. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/...
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12Z models in relatively good agreement with the overall track of the upcoming coastal system with near record cold in place at the beginning portion of the long range forecast. Arctic air initially in place Friday morning over northern New England will allow for a classic Nor`easter track along or near the Cape Cold Canal around daybreak. A slow commute is expected. Dynamic cooling aloft will continue as the H5 upper low shift north and east. H7 low to remain along or just south of our forecast area, keeping southern area in locally heavy precipitation. Several sites across our region will remain in a favorable dendritic growth zone. Snow may mix with sleet and rain along and near the coastline during the midday and afternoon hours. However, this will be after the majority of the precipitation has already fallen and accumulated. System exits to our east Friday night with mountain snow showers continuing, especially over the west, northwest facing high terrain. The atmosphere will be allow to modify on Saturday ahead of the next approaching strong cold front with H8 readings near around -4C. Snow showers may cross the region with the passage of this front Saturday night leading to a seasonably cool day with sunshine and Canadian high pressure on Sunday. Much more cold air will be building to our northwest on Monday as an Arctic front crosses the region during the afternoon hours. Snow squalls may accompany this system as low pressure develops over our region and shifts east. A weak weather disturbance will then shift east from the Great Lakes region midweek next week as below normal temperatures continue.
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&& .AVIATION /00Z THURSDAY THROUGH MONDAY/... Short Term...VFR tonight and thu. Conds lowering to IFR in snow over srn NH Thu evening overspreading the rest of the region by 03-06z. Long Term...IFR with areas of LIFR in RA, PL, SN and fog. Sfc wind gusts to 25 kt on Friday. && .MARINE...
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Short Term...Winds expected to gradually diminish this evening into the overnight hours. Have taken down the gale for the bays and the southern ocean zones. The rest will likely follow suit later this evening. Light winds for Thu but gales will likely be needed thu night once again. Long Term...Gale warnings will likely be needed once again for Thursday night into Friday as low pressure passes through the Gulf of Maine.
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&& .GYX WATCHES/WARNINGS/ADVISORIES...
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ME...Winter Storm Watch from late Thursday night through Friday afternoon for MEZ007>009-012>014-019>022-025>028. Winter Storm Watch from Thursday evening through Friday afternoon for MEZ018-023-024. NH...Winter Storm Watch from late Thursday night through Friday afternoon for NHZ001>006. Winter Storm Watch from Thursday evening through Friday afternoon for NHZ007>015. MARINE...Small Craft Advisory until 1 AM EST Thursday for ANZ151-153- 154. Gale Warning until midnight EST tonight for ANZ150-152.
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&& $$ NEAR TERM UPDATE...MLE

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