Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 040328 AAB AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 1028 PM EST Sat Dec 3 2016 .SYNOPSIS... A ridge of high pressure will slowly build into the region tonight and Sunday, before moving offshore Sunday night. A weak weather disturbance will bring some light snow to the region on Monday, especially southern and western sections of the forecast area. High pressure will settle in for Tuesday. Low pressure may affect the region with mixed precipitation Thursday and Friday with a cold blast following for the weekend. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 1025 PM Update... Upslope showers still reaching the ground especially in northern NH and the western Maine mountains. Light snow is also reaching the Notches but does not appear to be making it very far downstream. This pattern will persist overnight with a 20-30kt LLJ form the NW. Cold air arrives throughout the night with 850mb temperatures dropping to near -10 degrees C. Areas north of the terrain will see lows in the teens and lower 20s with widespread 20s downstream. Have adjusted PoPs, clouds, winds, and QPF/snow amount for the next several hours. 535 PM Update... No major changes to the forecast. Some dwindling snow showers in the region tonight with clearing skies across the coastal plain. Upslope showers continue overnight on northward facing slopes. A short wave trough embedded in the general cyclonic flow aloft will pass to the southeast of our CWA by early this evening. Any widely scattered rain and snow showers on the coastal plain should shut off by early evening as a result. However, upslope snow showers in the Whites will continue into the overnight hours with another 1 to 3 inches expected in NW-facing terrain. Wind gusts around 30 MPH very early on will diminish this evening. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... High pressure will build in on Sunday. Winds will be a little gusty through early-mid afternoon but nowhere near gusty as Saturday`s values. We`ll also see quite a bit more sun on Sunday as subsidence and drying in the column increases. High pressure settles over the region Sunday evening. This will allow for temperatures to plummet...allowing for lows in the teens in many areas. Clouds will begin to increase around midnight across southwestern zones a short wave trough approaches from the west. The clouds should spread northeastward and reach the coastal plain by dawn. Deeper layer moisture and ascent should arrive across southwestern NH between 5 and 7 am. This should allow for light snow to begin falling there during that timeframe...mainly across Cheshire County, but could possibly reach the MHT/ASH corridor by the morning commute as well. && .LONG TERM /MONDAY THROUGH SATURDAY/... Both ensemble and deterministic solutions are now in decent agreement on the longwave pattern through next weekend. We begin the period with a shortwave impulse over the eastern Great Lakes on Monday. It`ll weaken as it slides across New england along with an associated warm front. Some light overrunning wintry precipitation will be possible with this weak system. Ridging and fair weather will quickly follow this system for Monday night and Tuesday...in response to deepening upper trough over western CONUS. By Wednesday...the upper trough begins to slide east and in response our downstream ridge will exit the coast. At the surface...a surface low near Hudson Bay with an occluded front extending southeast to a a coastal low situated off the DELMARVA. There`ll be an initial shot of light overrunning precipitation on Wednesday...but only limited QPF given weakening shortwave and light precipitation trying to press northeast into offshore high and initially dry airmass. For Wednesday night and Thursday...the upper trough to our west goes negative tilt with faster GFS/CMC solutions preferred. The occluded front will pivot northeast across the region with cold air injection causing the coastal low to rapidly deepen as it crosses the Gulf of Maine late Thursday. Forecast thermal profiles suggest snow for the mountains and foothills...with rain along the coastal plain. In between...a messy wintry mix is likely. Still plenty of uncertainty regarding track and exact timing of coastal low deepening making QPF amounts and type challenging at this juncture. Blustery with the coldest weather of the season behind the system for Friday and the upcoming weekend with clouds and accumulating snows across the higher terrain. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... Short Term /through Sunday/...VFR conditions are expected tonight except for MVFR conditions in the mountains. VFR conditions everywhere on Sunday and much of Sunday night. Southwestern NH may start to see MVFR conditions in light snow developing between 10z and 12z Monday. Long Term... Mon...Areas of MVFR in -sn/-ra. Wed...Areas of MVFR in -sn/-ra. Wed night - Thu...IFR and lcl LIFR in ra/sn and fog. Sfc wnd gusts to 30 kt are psb. && .MARINE... Short Term /through Sunday Night/...SCA conditions continue tonight across the waters before subsiding late tonight and especially on Sunday. Long Term... Thu...Gales force winds are possible...with gusts approaching storm outside the bays. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 8 AM EST Sunday for ANZ150>152-154. && $$ NEAR TERM...Hanes SHORT TERM...Sinsabaugh

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