textproduct: Gray - Portland

SYNOPSIS

Winds continue to diminish this afternoon and tonight, while mountain snow showers gradually come to and end by this evening. There will be some steady improvement in daytime temperatures through the week as high pressure builds into the region, but the pattern will also lead to ideal conditions for overnight temperatures to get quite cold. Wednesday night in particular could be very chilly across the region. Some single digits are not out of the question in the northern valleys. The next chance for widespread precipitation will arrive on Friday, with mainly dry conditions this weekend.

NEAR TERM /THROUGH TONIGHT/

Key Messages: * Winds and mountain snow showers continue to decrease through the day and into this evening. * Chilly temperatures are expected tonight with widespread lows mainly in the upper teens to mid 20s.

Forecast Details: Northwest flow aloft persists this afternoon which should continue to bring plenty of clouds to the mountains and north country with clearing skies to the south. A few lingering snow showers will also remain possible over the higher terrain in Coos county in NH and northern portions of Oxford, Franklin, and Somerset counties in ME. However, this activity should continue to diminish as heights rise through the near and short term and the flow gradually deamplifies.

With the diminishing winds and clearing skies, we will likely see some decent radiational cooling south of the mountains tonight. Lows will generally range from the upper teens north, to the low to mid 20s south.

SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/

Key Message: * The coldest night of the forecast period is on tap for Wednesday night with lows forecast to mainly range from the low to mid teens north, to the low to mid 20s south.

Forecast Details: The flow continues to deamplify through the day on Wednesday as we transition to almost zonal flow aloft by Wednesday night. We finally may start to see some clearing in and around the mountains as surface high pressure starts to nudge closer. In short, this pattern should lead to a pleasant but cool Wednesday that will feature plenty of sunshine and calm winds. Temperatures will only be a touch warmer than today but the lack of wind should make it feel a bit warmer. Highs are forecast to range from upper 20s to 30s north, to the low to mid 40s elsewhere.

The coldest night of the forecast period then comes Wednesday night with plenty of clear skies and light winds. Lows will mainly range from the low to mid teens north, to the low to mid 20s south. A few single digit readings are not out of the question across some of the northern valleys.

LONG TERM /THURSDAY THROUGH TUESDAY/

Key Messages: * Quick, low moisture system into Friday afternoon and evening will bring rain showers to the area, with a brief wintry mix towards the mountains. Accumulating wintry precip, while light, looks mostly elevation based.

Details: High pressure overhead Thursday will see cool temperature continue, but more clouds are expected compared to Wednesday. Winds remain light overnight as temps dip into the mid 20s. This high will pull east as the next weather system approaches from the west.

Low pressure over Hudson Bay will swing an occluded front into the Northern Great Lakes with potential triple point low moving into NY state Fri morning. Nearing warm front will bring temp increase for the day overall, but only into the mid to upper 40s, with temps around 50 for the coast. Focus for the system will be a period of precipitation, most of which may be showery for bulk of the coast and interior. The mountains are expected to see the greatest QPF, but NBM and AI GFS both depict comparative amounts into the Kennebec Valley and Midcoast. Deterministic models are the most bearish outside of the mountains, likely emphasizing the lack of deeper moisture available. For precip types, model profiles are warm, and don't expect wintry precip outside of the mountains. Even here, the afternoon arrival may limit how much is seen in the valleys vs. higher elevations...especially as the pattern isn't too favorable for CAD.

Precipitation will taper Friday night, ending by Sat morning. Departing system will leave behind a breezy Saturday, but otherwise little change to going conditions. Forecast supports a dry weekend, with the NW surface flow continuing to bring in lower than normal temps. While clouds are forecast to stick around, this flow could lead to overnight lows in the upper teens for portions of northern NH and far western ME Sat night.

Into early next week, pattern becomes a little more active, but there remains little to no confidence in one particular system. Broad cyclonic flow will sink into the James Bay region with broad jet from the Midwest into Ohio Valley. This should be good transport for embedded shortwaves to move along which is what carries the confidence of a more active weather pattern.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

Short Term...VFR conditions are mainly expected through Wednesday night, but MVFR ceilings will likely hang on at HIE through the rest of today and tonight. A few snow showers will remain possible this afternoon across northern New Hampshire and northwest Maine. HIE has a low chance of seeing one of these showers through this afternoon.

Long Term...VFR expected Thursday, but clouds will be developing overnight into Friday. The prospect of MVFR ceilings developing Fri afternoon is increasing with SHRA across the area and SHRASN in the mountains. IFR ceilings possible into the overnight hours for the mountains. Trend towards VFR expected into Saturday, continuing Sunday. Will see SE winds Friday turning NW Saturday, with gusts around 15 kts. Despite surface inversion, LLJ not strong enough to mention LLWS at this time Saturday night.

MARINE

Short Term...Winds and seas will continue to relax through the day with SCA conditions subsiding by this evening. Winds and seas then remain below SCA criteria through Wednesday night.

Long Term...With frontal system moving through the region Friday and Friday night, will see a brief period of SCA conditions (winds and waves) during this time. Otherwise, limited surface features will keep winds and seas below SCA criteria. Will look towards early next week for next potential marine hazards.

GYX WATCHES/WARNINGS/ADVISORIES

ME...None. NH...None. MARINE...Small Craft Advisory until 7 PM EST this evening for ANZ150>154.