Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 221736 AAB AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 1236 PM EST Sat Feb 22 2020 .SYNOPSIS... High pressure will remain in control of the weather across northern New England through the weekend. Temperatures will really begin moderating today. High temperatures will climb above freezing for most areas today, with southern areas making a run at 50 on Sunday. Above normal temperatures continue into the beginning of next week. By the middle and latter portions of next week, a series of weather systems will likely bring a period of unsettled weather. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1235 PM Update... Much warmer day in progress compared to yesterday, with temperatures in the upper 20s to upper 30s across the area. GOES satellite imagery shows a few stubborn stratus clouds north of the higher terrain, along with some cirrus drifting southeast across northern New England. Made a few changes to sky cover as well as hourly temperature grids; however forecast is largely on track. 1028 AM Update... Made a few local changes to temperature grids based on observations. Otherwise forecast is on track with temperatures warming into the upper 20s/lower 30s north to the upper 30s/lower 40s south. Update...Minor changes to reflect latest observational trends. Previous discussion...A mostly mid/upper level front will cross the area this morning. There is little evidence of a surface reflection...with surface winds remaining WSW behind the upper trof. The nighttime microphysics composite image shows a pocket of trapped moisture behind the front...that is poised to move into the mtns today. Despite that...with surface winds remaining SWly and mid level winds Wly...the upslope signal is not a favorable one. I have pretty low PoP in the higher terrain...and prefer more flurry wording to actual chance of measurable precip in snow showers. Should see much of the area climb to at or above freezing for highs as moderating temps expected on the backside of the high pressure system sagging S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... Surface ridging builds back into the area tonight behind the departing front. We keep generally Wly flow aloft...with moisture steadily decreasing in the mid levels. This will mean a gradual decrease in upslope cloud cover into Sun morning. As we continue to moderate temps lows will be much warmer for most places tonight than the past couple. Readings will be right around 20 for most locations...with valleys that are able to decouple dropping into the lower teens or even single digits. On Sun even with conservative mixing offered by forecast soundings highs are likely to top out in the mid to upper 40s S of the mtns. It wouldn`t take much of a mixing height error...especially with SW surface winds to see readings in the 50s. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... Overview: Broad high pressure over the eastern U.S. will remain dominant Sunday night into Monday as our quiet stretch of weather continues. The rest of the long term period is expected to be more active as a pair of low pressure systems bring precipitation to our region. The first system (late Tuesday into Wednesday) looks less impressive than in previous days, but the second one (late Wednesday through early Friday) could bring significant precipitation in the form of rain and snow. Impacts: No high impact weather anticipated at this time...but the active period of weather next week will need to be monitored for potential impacts in the form of accumulating snow affecting roadways/commutes and/or rainfall potentially leading to ice jams. Details: A broad area of surface high pressure stretching over much of the eastern U.S. will begin to move east into the western Atlantic Sunday night into Monday as an area of low pressure moves through the south-central U.S. A weak disturbance will also be moving through Quebec over the same period, and an area of high pressure between the two systems will begin to nudge into New England late Monday. Overall, this part of the forecast is expected to be dry with warm temperatures. In fact, Monday looks like the warmest day of the long term period as highs approach 50 degrees in southern NH and southwest ME; some locations could rise into the lower 50s. Above average temperatures will continue through Thursday, though Wednesday and Thursday will be cooler than Monday and Tuesday. Global deterministic guidance continues to indicate that the weather for our region becomes decidedly more active and unsettled in the middle to latter part of next week. An area of low pressure is still expected to reach the Ohio Valley/western Great Lakes by Tuesday morning but will weaken as the day progresses. A few days ago, Tuesday looked like a rather wet day for our region, but the trend over this time frame has been toward a drier solution as the primary pieces of energy related to this system remain to our west and south. However, light rain showers will be possible for southern locations during the day and many locations in central and southern NH could see precipitation Tuesday night, likely in the form of light snow. Wednesday and Thursday will see another area of low pressure develop near or over our region as a potent upper-level trough develops over the central U.S. and moves east. The intensity and location of that trough will have an influence on the ultimate track of this second area of low pressure, which the latest deterministic guidance actually tracks right along the NH and southwest ME coasts. However, ensemble guidance again has potential tracks from the western Great Lakes to the outer portions of the Gulf of there will be much to figure out with this system as we get closer to this part of the forecast. The latest multi-model blended consensus temperatures favor a colder solution that would result in mostly snow or a rain/snow mix for all but the southernmost locations in the CWA...but again, this part of the forecast will likely change over the next several days. One thing to watch is precipitation amounts with this system. Latest ensemble guidance indicates that QPF amounts up to an inch are possible with this whether that falls as snow or rain, potential impacts such as accumulating snow affecting commutes or rainfall leading to ice jams on rivers would be possible. By Friday morning, the area of low pressure should be moving into New Brunswick, but the mountains will likely see continued upslope snow showers through the day in the wake of the system in west-northwest flow. After the extended run of above average temperatures, Friday and the weekend could see a return to near normal temperatures. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... Short Term...Widespread VFR conditions continue ahead of a weak front approaching from the NW. As SW flow increases ahead of the front some marginal LLWS conditions remain possible at HIE thru the morning. Otherwise some BKN MVFR CIGs will move into Nrn zones this afternoon with the front. Not confident that they move all the way into HIE...but I cannot rule out a stray flurry. Long Term...VFR conditions at all terminals Sunday night through early Tuesday. MVFR conditions thereafter under cloudy skies with potential periods of IFR conditions in -SHSN Tuesday night into Wednesday morning. && .MARINE... Short Term...SW winds are increasing ahead of a weak front that will cross the waters today. Marginal SCA conditions will continue into the early afternoon before winds and seas diminish. After that conditions remain below SCA thresholds thru Sun. Seas briefly build to 5 ft in the central and northern outer water zones on Monday before subsiding Monday night. An extended period of seas greater than 5 ft over the outer waters begins early Wednesday morning and continues through the end of the period as a series of low pressure systems affect the waters. Winds look to remain below 25 kt for the entire long term period. Long Term...Seas and winds below SCA criteria through Wednesday as high pressure dominates the region. Conditions become unsettled thereafter as a pair of low pressure systems affect the waters. Extended periods of SCA conditions likely from Wednesday night through Friday over the outer waters where seas are currently forecast to build to >10 ft Thursday into Thursday night. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Hanes SHORT TERM...Legro LONG TERM...Watson is the U.S. government's official web portal to all federal, state and local government web resources and services.