textproduct: Gray - Portland

SYNOPSIS

Warm front pushes through the area today bringing icy conditions across the interior and rain along the immediate coast. Cold front pushes through this evening, bringing with it blustery conditions through Tuesday. The remainder of the week remains cold with a possible arctic front to start the New Year.

NEAR TERM /THROUGH TODAY/

Key Messages: * A messy winter storm with a period of freezing rain is going to bring hazardous travel to the area through at least the morning commute.

Warm front precipitation shield will continue to push north and east through the area early this morning with freezing rain developing across most of the area by daybreak. Sleet and snow mix is possible across the Western Maine Mountains and Northern Kennebec River Valley at daybreak. The big question is how quickly the freezing line pushes inland over the next 12 hours. Most likely the only area that will be above freezing by the morning commute will be the NH Seacoast and the Necks of coastal Maine. Expecting widespread travel impacts for the morning commute with cold roads and freezing rain. The shallow cold air will hold strong across Central NH and into Western Maine through the morning hours when the bulk of the precipitation is expected to occur. This will lead to ice accretion approaching .5" in some areas of Central NH into the Saco River Valley if the QPF forecasts verifies close to an inch. Enough ice for some branches to snap in itself. The biggest impact though will be the winds expected during the evening. That is the big forecast challenge question, will these areas warm enough above freezing this afternoon to shed some of the ice or not? Currently temperatures are just barely above freezing in some areas under the Winter Storm Warning for mixed precipitation. Further towards the I-95 corridor and across Southern NH, temperatures will warm will into the 30s and even some low 40s, so any ice will melt by the afternoon commute, thus not expecting much for impacts for the majority of the population area.

SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/

Key Messages:

* Windy conditions return tonight ushering in much colder air, limited power outage threat, elevated power outage threat in areas that have ice bonded to tree limbs.

A potent upper low passes to our north tonight, with an 80kt low level jet rounding it's base. The surface cold front and developing triple point low over Northern Maine will help enhance the pressure gradient, allowing for gusty westerly winds. Wind gusts will be in the 20 to 30 mph with higher gusts in the terrain areas. While these winds aren't the most impressive, areas that do end up seeing higher ice accumulations will have an elevated power outage risk as ice loaded limbs snap. Low temperatures Monday night fall into teens across much of the area, so windchills will feel more like the single digits by Tuesday morning. Tuesday will be a blustery day with steepening low level lapse rates allowing for gusty winds and highs dropping back into the 20s, bringing windchill values into the single digits.

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/

A mid-level trough persists over the northeast through the second half of the week. This will allow for drier and colder conditions to prevail. High temperatures look to be in the teens and lower 20s Wednesday through the upcoming weekend.

Some wintry weather is possible Wednesday night and into Thursday as a shortwave connects with a favorable upper-level jet over the Gulf of Maine. However, most of this development appears to occur just after the system passes the area and snowfall totals are likely to be less than an inch in most places.

AVIATION /06Z MONDAY THROUGH FRIDAY/

Short Term...Low ceilings are expected to bring LIFR conditions through most of today with freezing rain changing to rain at the coast first, before pushing inland. Ceilings increase tonight as gusty westerly winds move into the area. VFR with gusty northwesterly winds are expected to continue into Tuesday.

Long Term...VFR generally expected Wednesday, though upslope snow showers may intermittently lower restrictions at HIE. A brief window of lower restrictions across the area is likely Wednesday night as light snow moves across the region. VFR expected after Thursday morning continuing through the weekend.

MARINE

Short Term...Warm front pushes through the area today with increasing southerly winds approaching small craft conditions. Wind shift to the west is expected by this evening as a strong cold front pushes across the coastal waters. Winds and seas will increase through the night and into Tuesday with Gale Conditions expected for about 24 hours.

Long Term...Gale force westerlies are expected Wednesday morning. Winds slacken a little during the day, with SCA winds likely continuing through the remainder of the week. 5-10ft seas are expected Tuesday and Wednesday, with 2-5ft seas likely by Friday.

GYX WATCHES/WARNINGS/ADVISORIES

ME...Winter Weather Advisory until 7 PM EST Monday for MEZ007>009- 012>014-018>028-033. NH...Winter Weather Advisory until 7 PM EST Monday for NHZ001-002- 010>015. Winter Storm Warning until 7 PM EST Monday for NHZ003>009. MARINE...Gale Warning from 7 PM Monday to 7 AM EST Wednesday for ANZ150- 152-154. Gale Warning from 10 PM Monday to 7 AM EST Wednesday for ANZ151-153.