textproduct: Gray - Portland

SYNOPSIS

Expect temperatures to remain below normal through at least Monday. Snow showers will stay mainly in the mountains, but widespread light snow is possible Monday night as a clipper moves through. High temperatures will remain in the 20s or colder through the upcoming weekend. A warmup arrives early next week with warmer temperatures likely by Wednesday.

NEAR TERM /UNTIL 6 AM FRIDAY MORNING/

630 PM Update... Skies are now mainly clear across the majority of the CWA and some locations are starting to decouple, which has already allowed temperatures to fall to near zero in those locations. The main thing to watch this evening will continue to be temperatures as the "floor" is quite low in locations where winds manage to go calm. Loaded in the latest sfc observations and tweaked winds but the fcst remains on track.

Previously... Update...Snow at RKD is finally tapering off with visibility improving from 1/2 to 1 mile. So I have cancelled the winter weather advisory with the threat of accumulation ending.

Previous discussion...The remainder of light snow is marching eastward as the cold front slices in from the west. Snow intensity is weakening with time but I could still see some visibilities near Penobscot Bay dropping to one half mile or less at times. Since the winter weather advisory is already in effect and this area of snow is approaching it I will keep it up, though once this has passed it should be able to be cancelled quickly.

Winds will become gusty for areas behind the cold front thru the mid to late evening hours for most places. Westerly gusts up to 30 to 35 mph at times are possible. It will at least remain breezy overnight as well as a secondary front drives thru with the real cold air. This brings wind chills down to around 20 to 25 below across the western Maine mtns and I have issued a cold weather advisory.

Behind that secondary front will also see upslope snow showers become more widespread, but this is mainly for the Fri forecast.

SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/

Fri will see temps back well below normal as the cold air mass settles into the region. Gusty westerly winds continue and will continue the upslope snow showers as much of the low level profile is forecast to be in the snow growth zone. NBM PoP was nil, so I have blended in some of the downscaled NAM PoP to place snow showers and flurries into the forecast. Given the unblocked cold advection regime, flurries should be capable of getting downwind of the mtns and maybe spilling towards the coast at times.

Fri night will remain cold, but with gradient winds stirring thru the night do not anticipate min temps to be quite as cold as tonight.

LONG TERM /SATURDAY THROUGH THURSDAY/

Key Messages: 1) Average to below average temperatures this weekend. 2) Light snow likely Monday night. 3) Possible warming trend mid-next week.

A 500mb trough will engulf the northeast this weekend, allowing for a colder than normal weekend ahead. Outside of a stray snow shower in the mountains, mostly dry weather is expected over the weekend. A weak clipper moves in Monday night, likely bringing some light snow to the area. A pattern flip occurs afterwards, with mid-level ridging starting to build in on Tuesday. This will allow for a warming trend through the mid-week, with highs in the upper 30s possible by next Wednesday and Thursday.

AVIATION /00Z FRIDAY THROUGH TUESDAY/

Short Term...Local IFR or lower conditions as the remaining snow slowly moves east. As the cold front marches across the forecast area conditions will return to VFR for all TAF sites except for HIE, where lingering MVFR CIGs are possible in upslope snow showers. That will continue thru Fri and Fri night. Behind the cold front this afternoon and evening westerly surface wind gusts of 20 to 25 kt are possible, and again Fri during the day.

Long Term...VFR expected over the weekend. Some upslope may allow for HIE to see some patchy lower restrictions. A more widespread lower restrictions arrives Monday night with light snow moving in.

MARINE

Short Term...Cold front is crossing the waters this afternoon with strong cold air advection kicking in behind it. Westerly winds will increase and gale force gusts are anticipated on all waters. The gale warning remains unchanged. Gradually as seas build and the colder air settles into the region, moderate freezing spray will develop. The freezing spray advisory also remains in effect. Winds and seas gradually diminish Fri but I could see a few gale force gusts at times well outside the bays. SCA conditions will likely continue thru the period.

Long Term...SCA westerlies die down through the day on Saturday. Winds shift to northwesterlies, and briefly strengthen back to SCA thresholds by Sunday night. Winds subside again as they shift to southwesterlies at 8-12kts by Monday night. Seas of 2-4ft are expected through the entire extended forecast.

GYX WATCHES/WARNINGS/ADVISORIES

ME...Cold Weather Advisory from midnight tonight to 10 AM EST Friday for MEZ007>009. NH...None. MARINE...Gale Warning until 7 AM EST Friday for ANZ150>152-154. Freezing Spray Advisory from 10 PM this evening to 1 PM EST Friday for ANZ150>154. Small Craft Advisory until 7 AM EST Friday for ANZ153.