textproduct: Gray - Portland

SYNOPSIS

Cold and blustery conditions continue into tonight. The remainder of the week remains cold with an arctic front bringing accumulating snow Wednesday night to kick off the new year. Cold temperatures and mountain snow shower activity lasts into the weekend.

NEAR TERM /THROUGH TONIGHT/

Impacts and Key Messages: * Wind gusts through the afternoon pose an elevated power outage risk for areas where trees have, or were damaged by, ice and snow load.

Unblocked flow out of the mountains is allowing some light snow showers to reach into the foothills and southern coast of Maine this afternoon, but this activity tapers off into the evening as flow becomes more zonal aloft and brings the upslope showers to an end. Many stations are still observing frequent gusts 25-35 mph, so left wind advisories in place to cover the remainder of the power outage threat.

Clouds clear some overnight tonight, but most locations stay breezy enough to avoid decoupling. Still, this fresh airmass overhead will allow temperatures to fall into the mid- to low teens from the foothills south. In the foothills and points north, temperatures will drop into the single digits to zero. Regardless, bitterly cold windchills will make it feel below zero just about everywhere.

SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/

Impacts and Key Messages: * Accumulating light snow may make travel slick around the time of New Year's Eve festivities.

Flow becomes southwesterly Wednesday, so would expect to see clouds increasing as the day goes on. At the surface we stay dry, with the warm air advection aiding high temperatures rising into the mid- to upper 20s south of the mountains. To the north, temperatures rise into the upper teens and low 20s. Winds look breezy during the peak mixing hours so it will likely feel 10-15 degrees cooler.

New Year's Eve festivities may include some snow flakes as a stationary front draped over the region begins to move north as a warm front. At the same time a sharp shortwave trough crosses the area. The timing looks like the countdown to the New Year may feature light snow with accumulations beginning as festivities wrap up. Soundings show ample lift through the DGZ, but the question is how saturated the column will be. Models are in reasonably good agreement that low pressure deepens off the coast which would add an onshore wind component and thusly a moisture feed. For this reason, coastal locations may see the best snowfall overnight on the order of half an inch to an inch through sun rise. Interior locations are more likely to see a half inch or less, with higher terrain seeing locally higher amounts as an upslope component returns on the back side of the shortwave. This light accumulating snow may make for some slippery travel as you head home from your holiday festivities.

LONG TERM /THURSDAY THROUGH TUESDAY/

Key Messages: * Quick system continues through the area Thursday resulting in light snowfall for much of the area. Snow will likely be falling during the morning commute, particularly for the coast.

Details: Disturbance out of the Great Lakes continues through the Gulf of Maine Thursday. The system will still be strengthening and consolidating through the Gulf before pushing NE at strength. Thus while most of the expected impacts are light, there is some potential for overperformance of QPF (and snow) towards central ME and the Midcoast. For now, carry totals through Thurs of 1 to 3 inches, with the bulk of the forecast area seeing around one inch.

Increased winds Thursday as pressure gradient tightens and NW 925mb winds increase w/ low pushing into New Brunswick/Nova Scotia. These usher in cooler temps, where highs may be met in the morning and fall through much of the afternoon. Thursday night lows will be in the single digits above and below zero as winds slowly lighten. The coast and interior could see winds fall off earlier, resulting in good radiational cooling conditions for late night. Brought lows down a couple degrees for this region, where a spare -10 can't be ruled out for ideal locations.

Quiet weather settles in for Friday and the weekend. It will be cool, with temperatures running below normal and daily NW breeze that keeps wind chill values between -10 and 10.

The next chance for widespread precip could arrive early to mid-week next week in the form of a robust clipper, but there remains a lot of solutions in guidance. This is mainly in placement of moisture between high pressure in the central CONUS and north flow across southern Canada.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

Short Term...West-southwesterly wind gusts 20- 25 kts continue into tonight at most terminals, but visibility and sky conditions remain VFR through the day Wednesday. The next chance for flight restrictions comes Wednesday night as widespread light snow will likely bring about MVFR or lower visibilities.

Long Term...MVFR ceilings with some IFR will improve through the day Thursday as SN tapers west to east. IFR vis likely in elevated SN rates for coastal terminals Thurs AM. VFR is expected by sunset for most terminals, with some light SN continuing for HIE and US/CAN border terminals. Gusty NW winds Thursday afternoon 20 to 25 kts, some to 30 kt. High pressure brings mostly VFR conditions for the weekend, but MVFR ceilings may be intermittent for HIE.

MARINE

Short Term...Westerly Gale force wind gusts continue into Wednesday morning before beginning to become less frequent. Afterward southwesterly wind gusts greater than 25 kts last through the afternoon before weakening Wednesday night. SCAs are likely going to have to remain up through at least the first part of Wednesday night as wave heights take a little bit longer to fall below 5ft. Light freezing spray will also continue into Wednesday morning, with more moderate freezing spray likely in the slightly colder waters of Penobscot bay overnight tonight.

Long Term...SCA likely needed Thursday as winds remain due to strengthening low pres in the Gulf of Maine. Some Gale force winds will be possible in the northern coastal zones in proximity to the low. Wave heights may not get more than 4 ft as direction remains offshore for much of the 2nd half of event. Cold air advection may keep SCA continuing through Friday and Saturday outside of the bays/harbors.

GYX WATCHES/WARNINGS/ADVISORIES

ME...Wind Advisory until 7 PM EST this evening for MEZ007>009-012- 013-018-019-023-024-033. NH...Wind Advisory until 7 PM EST this evening for NHZ001>015. MARINE...Gale Warning until 7 AM EST Wednesday for ANZ150-152-154. Gale Warning until 1 AM EST Wednesday for ANZ151-153. Freezing Spray Advisory from 7 PM this evening to 7 AM EST Wednesday for ANZ151.