Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 212341 AAA AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 641 PM EST Wed Feb 21 2018 .SYNOPSIS... A cold front will cross the region this evening with cooler air filtering in for tonight and Thursday. A weak weather system passing south of the region on Thursday may spread some light rain and snow to southern areas before high pressure builds overhead Thursday night through early Friday. A series of weather systems will move through the region beginning late Friday and continuing through the weekend with mixture of precipitation. Fair weather returns for early next week. && .NEAR TERM /THROUGH THURSDAY/... Update...Mainly adjusted temps and dewpoints for the timing and strength of the cold front dropping Swd across the area. That speeds up the timing of colder air for much of the forecast area...but other than that there are no significant changes. I have extended the flood watch in time...as the CT River continues to rise in Coos County. Will be monitoring North Stratford closely for a flood warning. Previous discussion...All time record high temperatures have been set for the states of New Hampshire and Maine this afternoon. Final values still to be determined, but 70 degree temperatures are widespread in the southern half of New Hampshire and southwest Maine. Meanwhile a cold front is moving in from the north, with temperatures dropping and winds picking up out of the northwest accompanied by abundant cloud cover. Temperature drops of 10 degrees in one hour have been observed. This front will continue to push southeast across the area this evening. There have been a few pockets which have yet to reach full warming potential. Augusta/Waterville/Rockland area just finally began to mix and warmed into the 50s. These areas could hit 60s before the front moves through. Lebanon, NH has also been slow to warm being in a deep valley that has been slow to mix out. However, Springfield, VT was similarly situated and just saw a 10 degree rise in an hour, so will maintain forecast for a brief warm up at Lebanon before the front moves through. By morning we should see subfreezing temperatures over much of the northern part of the area. Went above guidance for low temperatures south of the mountains where downsloping winds and a good pressure gradient should keep things well mixed, with low level temperature forecasts indicating temps only falling into the mid 30s by dawn. && .SHORT TERM /THURSDAY NIGHT/... High temperatures on Thursday will likely be in the morning with cold advection continuing through the day. A weak wave will move through southern New England and spread some light precipitation into southern New Hampshire and far southwest Maine during the day. Believe it or not, there is a strong chance this will fall as snow with up to an inch accumulating even after the 75 degree temperatures observed today. This system will move quickly east Thursday evening with high pressure settling into the region. The center of the high moves through the northern part of the area, so expect excellent radiational cooling conditions here. Current forecast is for low single digits in the northern valleys, but below zero is possible. Again remarkable considering the upper 60s seen there today. Further south lows will mostly be in the teens apart from the colder spots. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... The overall long wave pattern with a trough over the West and a ridge over the East will slowly break down during the long term period as cold air seeps southward across the northeastern U.S. Weak systems will cross the region both Friday and again on Sunday. Precipitation type will be the main forecast challenge with these systems as high pressure to the northeast will lead to cold air damming across the region in both cases. At this time the ensembles favor a mainly light snow event inland for Friday with a mix along the coast. Surface temperatures will also contribute to the uncertainty in southern areas with readings in the mid 30s. High pressure will build east into the region for Saturday with temps warming into the 40s in all but the mountains. As the high moves off to the northeast Sunday, another cold air damming scenario will likely develop as the main area of low pressure moves northeast through the Great Lakes. This could lead to a mixed precipitation event across southern and central areas as the cold air damming could be a bit stronger than Friday, but with somewhat warmer temperatures aloft. By Monday and Tuesday, high pressure moving in from the west will lead to fair weather and cooler temperatures. With northwest flow, the mountains could see cloudy skies and the chance of snow showers. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... Short Term...A cold front moves through tonight shifting winds to the northwest. This could bring some MVFR conditions to Whitefield but for the rest of the area it should stay VFR. Some light snow is possible in southern New Hampshire on Thursday, bringing IFR conditions. VFR area wide Thursday night. Long Term...IFR to LIFR conditions possible Friday and Sunday in snow and mixed precipitation. Freezing rain is also a possibility on Sunday. && .MARINE... Short Term...Southwest winds gusting to near 25 KT will keep the Small Craft Advisory in effect this afternoon. As the front moves through tonight, winds will shift to the northwest and again gust to about 25KT before diminishing Thursday morning. Long Term...SCAs likely all waters Sunday continuing through Monday evening for the outer waters. && .HYDROLOGY... Flood Watch remains in effect for northwest New Hampshire primarily for ice movement on the northern Connecticut River. There is a chance that some ice jams may cause flooding here through tonight before colder air tries to solidify things again beginning on Thursday. && .CLIMATE... All time warmest temperatures for the month of February observed in the states of Maine and New Hampshire today. All time record highs for February also set at Concord and Portland, with Augusta still in range of setting theirs. Below is a list of the previous records before today`s warmth. ***FEB 21 RECORD HIGHS*** PORTLAND CONCORD AUGUSTA 59 - 1953 64 - 1872 52 - 1981 ***MONTHLY RECORD HIGHS FOR FEBRUARY*** PORTLAND CONCORD AUGUSTA 64 - Feb 26, 1957 69 - Feb 24, 2017 60 - Feb 18, 1981 ***STATEWIDE RECORD HIGHS FOR FEBRUARY*** MAINE: 68 in Sanford, ME on Feb 22, 1997 NEW HAMPSHIRE: 73 in Nashua, NH on Feb 24, 2017 && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...Flood Watch until midnight EST tonight for NHZ001>003-005. MARINE...Small Craft Advisory until 8 AM EST Thursday for ANZ150-152- 154. && $$ NEAR TERM...Legro

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