Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 220805 AFDGYX Area Forecast Discussion National Weather Service Gray ME 405 AM EDT Wed Mar 22 2017 .SYNOPSIS... An Arctic cold front crossing the area early this morning will bring much colder temperatures and strong northwest winds today and tonight. Very cold temperatures will continue through Thursday. A warm front will move in from the west on Friday with some light snow and rain ahead of it. Warmer temperatures will not last long, though, as another cold front drops down from the north on Saturday with more cold air expected for Sunday and Monday. Low pressure tracking south of New England on Monday could bring some light snow or a wintry mix of precipitation Monday into Monday night. Another low pressure system will track through New England on Wednesday with another chance of wintry precipitation. && .NEAR TERM /TODAY/... An Arctic cold front is moving into the area this morning, with some light snow spreading in behind it in the mountains. Expect strong cold advection through the day today with 850 MB temperatures dropping about 12C from 12Z to 00Z today. This strong cold advection will promote excellent mixing of the low levels today, especially to the southeast (downwind) of the mountains. Winds aloft are about 40 to 45 KT and although this is a little lower than what we would typically like to see for a solid Wind Advisory type of day, the strong cold advection and downsloping winds should maximize the mixing potential to the southeast of the mountains, allowing the strongest winds aloft to mix down. As a result, we have issued a Wind Advisory for the areas that have the potential to see 45 to 50 MPH wind gusts today. Winds aloft strengthen a bit this evening, and it is possible that the strongest wind gusts may well occur in the late afternoon or early evening. Thus the Wind Advisory will be in effect until midnight when the gusts should begin to diminish just a bit. Temperatures today will be falling from their early morning levels, generally through the 20s as the day goes on. && .SHORT TERM /TONIGHT AND THURSDAY/... Winds will diminish somewhat as the night goes on, but we should still see a fairly windy night. Although we will not see good radiational cooling conditions, temperatures will still drop from cold advection alone. By morning most of the area will be in the single digits, with some below zero readings possible to the northwest of the mountains where the best low level cold air gets banked up against the terrain. Wind Chill values will be below zero area wide and near 20 below in the Maine mountains. We may have to consider a Wind Chill Advisory if current forecasts hold. Record low temperature for Portland on Thursday, March 23 is 11 degrees set in 1959. The current forecast calls for this record to be broken. At Concord the record low is -10 set in 1875 and is not under threat of being broken. High pressure slowly moves toward the area on Thursday with lighter winds expected and slightly warmer temperatures. Most areas will only see the temperature top out in the low 30s (20s north of the mountains). && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... As the high pressure shifts offshore Thursday night...low temps will still be below normal for this time of year in the single digits to upper teens. The series of frontal systems on Friday and into Saturday will allow for weak over-running precipitation across the region. Due to the cold morning lows temps on Friday...all precipitation will start as snow and southern and coastal areas will transition to rain in the afternoon. Models are still showing difference in areal extent of the warming with ECMWF remaining colder. As noted in previous discussions...the QPF amounts are low and this should have minimal impacts. But...we should be mindful of the chance of precipitation during commuting times on Friday. Looking for lingering rain or snow showers to gradually end around midnight as the cold frontal boundary moves through the region. Saturday will have near normal to above normal temperatures and isolated rain and snow showers. Temperatures will drop back below normal on Sunday into Monday. Models are in better agreement for the system affecting the area Sunday night into Monday that will have the potential for wintry mix to include a chance of freezing rain from the foot hills to the coastal plain. There is a tight temperature gradient just offshore and the location of this will be part of the deciding factor on precipitation type. All models continue to show a series of systems going through the area early next week with potential for a mixed bag of precipitation. Confidence is low for this time frame on precipitation type and will mainly trend toward SB with minimal changes. Climate outlooks in Week 2 tend to show chance of warmer than normal temperatures and above normal precipitation. After looking at climate teleconnection...we will see a swing back and fourth in temperatures above and below normal temperatures as most remain in the positive phase but trend towards negative for a bit. At this point...there is a series of weather system with small amounts of QPF through day 7 which is below the 0.75 to 1 inch a week normal values this time a year. So we will need an increase in weather systems to have above normal precipitation and this should not be ruled out. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... Short Term...Expect VFR conditions through the period outside of some MVFR ceilings and light snow at Whitefield mainly this morning. Northwest winds will gust to 30 to 40 KT today, mainly to the southeast of the mountains. These wind gusts will diminish a bit late tonight, but still expect 15 to 25 KT through Thursday. Long Term...Expect a mixture of VFR and MVFR/IFR ceilings and visibility through Sunday because of the serious of frontal systems and lingering moisture from the showers. && .MARINE... Short Term...Strong cold advection behind an Arctic cold front is expected to bring gale force northwest winds to the waters today with winds eventually falling below gale force later tonight. As the cold air arrives, the winds will promote freezing spray, and a Freezing Spray Advisory continues into Thursday morning. Long Term...Expect a transition to small craft as the winds diminish on Thursday morning through Friday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Wind Advisory from 10 AM this morning to midnight EDT tonight for MEZ012>014-018>028. NH...Wind Advisory from 10 AM this morning to midnight EDT tonight for NHZ004-006-008>010-012>015. MARINE...Freezing Spray Advisory from 7 PM this evening to 10 AM EDT Thursday for ANZ150>154. Gale Warning from 8 AM this morning to midnight EDT tonight for ANZ153. Gale Warning from 8 AM this morning to 8 AM EDT Thursday for ANZ150>152-154. && $$ LONG TERM...Becker

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