textproduct: Gray - Portland

SYNOPSIS

Winds ease this morning as high pressure crosses northern New England. A weak Alberta clipper system will track north of the area tonight and Sunday, but only light snow or snow showers are expected across the north. A cold airmass follows this system to start the week. Another clipper is then possible by Tuesday.

NEAR TERM /THROUGH TODAY/

Seasonable air returns today as high pressure crosses through New England. Highs warm into the 30s across the south, with 20s across the north. Upslope snow showers dissipate in the morning across the north, with mainly sunny skies downwind of the mountains through midday. Clouds then begin to increase late in the day ahead of the next approaching system.

SHORT TERM /TONIGHT THROUGH SUNDAY/

An Alberta clipper tracks north of the Great Lakes and through Quebec tonight and during the day on Sunday. This brings a warm front through northern New England overnight. Temperatures will mostly hold in the upper teens and 20s overnight, but likely begin to rise along the coastline overnight as southwesterly flow increases. The warm front may bring some light snow showers to northern areas as it passes through overnight, but conditions look dry elsewhere with mainly clouds expected.

Much of the day on Sunday is spent in the warm sector of the clipper system. With partly sunny skies, temps warm into the upper 30s to low 40s for most spots. Across the mountains and foothills, mainly low to mid 30s are expected.

The cold front associated with the clipper then crosses during the afternoon hours on Sunday. Some snow showers are likely across the north and through the higher terrain with the front's passage in the late morning to early afternoon. These then most likely dry up as they move southward. Temperatures then begin to steadily fall in the late afternoon behind the front as a much colder airmass begins to move back into northern New England.

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/

Friday evening long-term update...No major changes were made in the long-term with latest NBM. Global models are starting to latch onto another weak wave that may bring some additional light snow to parts of the area on Christmas Day, but there's quite a bit of discrepancy on timing and location of the wave this far out.

Previous long-term discussion...

Sunday night will be fairly chilly behind the front as lows dip into the lower single digits above zero north, to the mid to upper teens south. It will likely stay fairly breezy through the night so wind chills may bottom out close to 10 below zero north, to the single digits above across the south. Monday should mainly be dry as high pressure moves into the region with below normal highs ranging from the lower teens north to the upper 20s and lower 30s south. That being said, we may see the usual snow showers stick around in the mountains given upslope westerly flow.

A ridge axis crosses the region Monday night and then the next progressive clipper/shortwave moves into the area on Tuesday. This clipper should have a little more moisture to work with but amounts will still be fairly light. Given the forecast temperatures, most of this precipitation should be in the form of snow but some rain or a mix or rain/snow will be possible along the coast. The best chances for a few inches of snow will be over the higher terrain but we could see enough widespread light snow for most in the forecast area to see a White Christmas. Highs will be a bit warmer on Tuesday, ranging from the low to mid 20s north to the mid to upper 30s south. The bulk of the precipitation should move out by Tuesday evening but snow showers will likely continue into Wednesday over the mountains in northwest upslope flow.

We should mainly dry out by Wedensday evening (Christmas Eve), which should help Santa's travel across New England overnight. As of now, it appears the dry weather will continue for Christmas Day with slightly warmer temperatures. The next shortwave then approaches Christmas night into Friday which brings our next widespread precipitation chances but details remain unclear a week out. At an early glance it looks very similar to the progressive clippers we will see earlier in the week.

AVIATION /06Z SATURDAY THROUGH WEDNESDAY/

Short Term...Mainly VFR continues through Sunday morning, with any lingering MVFR ceilings at HIE improving this morning. Westerly wind gusts of 25- 30kt ease this morning. MVFR ceilings are then possible Sunday afternoon across northern terminals.

Long Term...VFR conditions return on Monday, with another system possibly bringing more restrictions Tuesday that may last into the first part of Wednesday. Otherwise, upsloping could bring MVFR ceilings and snow showers at HIE the rest of the day Wednesday.

MARINE

Short Term...Westerly gales ease this morning as high pressure crosses the waters. Southwesterly gales likely then develop tonight ahead of an approaching cold front. The front crosses the waters late Sunday afternoon, with SCA conditions or marginal northwesterly gales possible behind the front by Sunday evening.

Long Term...Northwesterly gales are then possible behind the front Sunday night into Monday, and this will be followed by another period of at least SCA conditions Tuesday into Tuesday night as another clipper crosses the waters. Conditions then improve Wednesday through Wednesday night as high pressure builds across the region. High pressure shifts east late in the week as another front approaches.

GYX WATCHES/WARNINGS/ADVISORIES

ME...Wind Advisory until 8 AM EST Saturday for MEZ007>009-012>014- 033. NH...Wind Advisory until 8 AM EST Saturday for NHZ001>006. MARINE...Gale Warning until 10 AM EST Saturday for ANZ150-152-154. Gale Watch from Saturday evening through Sunday afternoon for ANZ150>154. Gale Warning until 7 AM EST Saturday for ANZ151-153.