textproduct: Gray - Portland

SYNOPSIS

Low pressure developing over the Great Lakes will send moisture into New England through the day with light rain developing tonight. A cold front crosses Wednesday night into Thursday bringing blustery conditions by Thanksgiving through the holiday weekend. Another cold front approaches later in the day on Sunday.

NEAR TERM /THROUGH TONIGHT/

A warm front lifts through New England tonight. This brings a period of mainly light rain across the area through the evening and overnight hours. A brief period of light freezing rain is possible in some cooler pockets across the northern valleys. Even here temps quickly warm to freezing after the precip starts, with mainly rain continuing into the morning.

SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/

Much of tomorrow is spent in the warm sector of a large system centered across the Great Lakes. However, it won't feel like in most locations as a lingering cold air dam keeps a shallow low level cool airmass in place with low clouds, sprinkles, and periods of drizzle. This will mostly be found through and east of the mountains and foothills, with temps mostly lingering in the low 40s much of the day.

The areas most likely to break into the warmer air and see a few breaks of sunshine by the late afternoon will be across southern New Hampshire, the Connecticut River Valley, and the far southern Maine coast. Here, temps climb into the 50s through the day, with some highs near 60 degrees along the Mass border.

During the overnight hours, a weak triple point low brings one more round of organized showers through tomorrow night. The steadiest rain is likely to be found across the north. This mostly moves through by daybreak on Thanksgiving, with only some lingering rain and snow showers across the higher terrain. The cold front pushes offshore by daybreak as well, with an increasing westerly breeze.

LONG TERM /THURSDAY THROUGH TUESDAY/

Precipitation will be largely over with to start out Thanksgiving morning as low pressure begins to lift up into the Canadian Maritimes. There could be a few snow showers in the mountains, but looks like the low-level wind direction will be more southwesterly and doesn't really favor the upslope precip. Otherwise, it'll be breezy with gusts of 25 to 35 mph based on forecast soundings and highs in the 40s south of the mountains. In general, expect to it be partly cloudy, but with the upper-low still lurking to the north and west, I think there will be periods of mostly cloudy skies.

Surface low pressure remains over the Maritimes Friday and Saturday resulting in a blustery couple of days with a tight pressure gradient over New England. Temperatures will be on a downward trend with CAA with highs in the mid 30s to low 40s south of the mountains Friday and then largely in the 30s by Saturday, but the winds will make it feel even chillier. Based on forecast soundings, looking at westerly wind gusts of 25 to 35 mph, but there's potential for some to exceed 40 mph on Friday per the top of the mixed layer on NAM forecast soundings. Periods of snow showers are likely in the mountains Friday into Saturday as the wind direction favors upslope precip, and Froude numbers indicate unblocked flow. So we may need to add a chance of snow showers south of the mountains in future updates, especially on Friday.

High pressure returns late Saturday into the first part of Sunday, but it quickly shifts east as a cold front approaches the region and brings the next shot as widespread precipitation. Models are favoring a more northward track of the low, which could bring mostly rain south of the mountains Sunday into Sunday night, but there could be rain/snow mix if precip begins early enough before the column warms. Will also have to watch for gusty winds along the coast as some deterministic solutions are showing a pretty stout low- level jet.

There's pretty good agreement in precip ending either late Sunday night or early Monday once the cold front crosses. However, the pattern remains active with troughing continuing over the Northeast, and it's possible another system is already approaching around next Tuesday. So the NBM PoPs of 40-50% seem very reasonable given the support from ensemble guidance.

AVIATION /17Z TUESDAY THROUGH SATURDAY/

Short Term...VFR quickly drops to IFR and LIFR late this evening too around midnight as rain and low ceilings move in. HIE likely only drops to MVFR ceilings tonight and tomorrow. Elsewhere. LIFR-IFR linger through at least midday Wednesday, then some MVFR breaks are possible at LEB, MHT, CON, PSM, and PWM in the late afternoon. IFR likely returns tomorrow night with another round of showers, and then ceilings gradually improve back to MVFR toward daybreak on Thursday.

Long Term...Mostly VFR Thurs-Saturday night except for periods of MVFR ceilings and snow showers will be possible at HIE. It will also be breezy during the daylight hours with 25-30 kt at times, possibly over 35 kt at times. This will be mainly 13Z-21Z each day with the breezier day expected to be Friday. Chances for precipitation and flight restrictions increase as a cold front approaches the region on Sunday. At this time, precipitation type favors mostly rain (except snow at HIE), but there could be a rain/snow mix as far south as AUG/LEB.

MARINE

Short Term...Marginal SCA conditions continue into late tomorrow morning as a warm front crosses through tonight. A cold front then crosses the waters late tomorrow night and Thursday morning, with a building period of SCA conditions late tomorrow night in SW-W winds ahead of any gale conditions on Thursday.

Long Term...West to southwesterly gales are looking more likely from Thursday all the way through Friday night as a tight pressure gradient sets up with low pressure over the Canadian Maritimes. High pressure brings a brief period of improvement Saturday night and the first part of Sunday before a southerly flow increases ahead of a cold front that looks to cross Sunday night or early Monday. There may be a period of gales with this system as well.

GYX WATCHES/WARNINGS/ADVISORIES

ME...None. NH...None. MARINE...Small Craft Advisory until 10 AM EST Wednesday for ANZ150-152- 154. Gale Watch from Thursday afternoon through Saturday morning for ANZ150-152-154.