Area Forecast Discussion
Issued by NWS Portland, ME

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048 FXUS61 KGYX 180150 AFDGYX Area Forecast Discussion National Weather Service Gray ME 950 PM EDT Sat Mar 17 2018 .SYNOPSIS... A very cold night is on tap tonight in the wake of a cold front for tonight. Below normal temperatures are expected to continue through at least mid week as winter holds on. One or more low pressure systems are expected to develop off the mid Atlantic coast midweek and currently look to pass far enough south of our area to keep us dry. && .NEAR TERM /THROUGH SUNDAY/... 941 PM update... going to update a little early to make some adjustments on current conditions. So winds dropping off quickly especially across the north. As soon as the winds dropped, so did the temps, right off the cliff. Crystal clear skies, little to no wind, and maybe even a touch of fresh snow across the north with earlier snow showers has lead to ideal radiational cooling conditions. Of note, the air is so optically clear, that Mount Washington observers have been reporting 130 mile visibility for several hours now. Cold spots in northern New Hampshire and the western mountains of Maine were approaching 0F last hour so have made some big cuts in the overnight lows. Most of the guidance available is too warm compared to current temps, and model dewpoint guidance is way too high compared to the obs. All in all the usual suspects overnight should make it down to -10F or so, and honestly would expect to see a few isolated spots hit -15F or more. Temperatures adjustments outside of the north country are less dramatic, but still dropping things a few degrees right down to the coastline. As of changes to the forecast. Wind gusts dropping out rapidly as sun sets and best surge of cold advection pushes through. Temps in the teens with even a few single digits in the mountains. Already have some cold numbers for the overnight but will watch to see how things track as with clear skies and excellent radiational conditions going lows may not be low enough. At 18z...the cold front extended from the gulf of Maine through southern New England. Northwest winds gusting between 30 and 40 mph at times accompanied the frontal passage along with a few snow showers. For tonight...skies will clear in all but mountain sections as upslope flow continues to generate some clouds and perhaps a stray flurry. Winds will drop off and with the snowpack and deepening cold airmass temperatures will drop to around zero along the international border...and in the single number to lower teens elsewhere. && .SHORT TERM /SUNDAY NIGHT/... On Sunday...we should see some fair weather clouds develop in daytime heating...especially across northern and eastern sections in proximity to the upper low. Otherwise...another well below normal day in the temperature department with highs a few degrees either of 20 in the mountains and in the 20s elsewhere. A few clouds are possible Sunday night across northern and eastern sections as a weak shortwave crosses the area. Otherwise...another seasonably cold night with low temperatures similar to tonight. && .LONG TERM /MONDAY THROUGH SATURDAY/... Blocky pattern across the CONUS and Canada will continue through early to mid week. The pattern looks to configure itself such that it keeps southern stream waves suppressed to the south of New England. One such wave moves off the Mid Atlantic coast Tuesday but consensus in deterministic and ensemble runs is for it to remain far enough south to keep our region dry. Another wave - this one potentially stronger - is loosely agreed upon to develop off the Mid Atlantic coast later Wed and Thu and also move far enough offshore to allow for dry weather here. There continues to be spread in ensemble members here with both waves, especially the second one. This should come as no surprise given the blocky, short wave-laden pattern across North America. Therefore, confidence in midweek outcome is still low and may be for several more days. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... Short Term /through Sunday Night/...VFR with few to no clouds through the period. Gusts rapidly subsiding early this evening. Long Term...VFR conditions are expected Monday through Thursday at this time with dry weather expected. && .MARINE... Short Term /through Sunday night/...Winds starting to drop off and losing the big gusts, but still experiencing SCA conditions. Tomorrow SCA conditions are less certain. Debated extending but will leave this decision to the overnight forecasters. For Sunday and sunday night...SCA conditions remain possible for much of the time outside the bays. Long Term...SCA conditions will be likely midweek. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 6 AM EDT Sunday for ANZ150>154. && $$ SYNOPSIS... NEAR TERM...Schwibs/Manning SHORT TERM...Schwibs LONG TERM...Ekster AVIATION...Manning MARINE...Manning is the U.S. government's official web portal to all federal, state and local government web resources and services.