textproduct: Caribou

SYNOPSIS

High pressure continues to build in from the west tonight, with the high also exiting to the east on Tuesday. An area of low pressure passes to the north Tuesday night into Wednesday night, followed by high pressure on Thursday, then a second low passing to the north Thursday night though Friday night. High pressure builds in on Saturday.

NEAR TERM /THROUGH TUESDAY NIGHT/

Key Messages: *Blowing snow and light snow showers this afternoon *Warming temperature trend begins tomorrow

Ridging builds in from the west tonight through early tomorrow. A tightened pressure gradient lingers over the state, between a maritime low to the southeast, and a building high pressure to the southwest, with some gusty winds continuing throughout northern and central Maine until this evening. Very light precipitation coming off of the St. Lawrence river, but little to no snow fall accumulation is expected with these showers. Confined snow showers to northeast Aroostook county. This fluffy snow, combined with the snow that fell last night, results in some blowing and drifting snow around agricultural areas, which can reduce visibility and accumulate snow sporadically on roadways. Always exercise caution when driving in blowing snow conditions. Winds and snow showers gradually relax overnight. Overnight lows in the single digits inland, and low-teens along the coastline. Some of the lingering winds could cause wind chills below zero.

Tomorrow, ridging stays over Maine, resulting in calm southwesterly winds, and dry conditions. Daytime highs in the low-20s in the north, and mid-to-upper 20s Downeast. Ridging persists throughout the state until later that evening, as a low-pressure system off to the the west moves closer to western Maine, bringing a warm front and precipitation to enter the region. By late night, precipitation just begins to enter the region and Crown of Maine. Overnight lows in the teens for inland areas, and low-20s along the coast. Temperatures slowly begin to rise starting Tuesday night, throughout the rest of the week.

SHORT TERM /WEDNESDAY THROUGH THURSDAY/

Key Messages: * A coating to 1 inch of snow is possible Wednesday afternoon and evening across the north, with up to 2 inches over the mountains. * Temperatures return to above normal.

SW flow will advect warmer air into the area on Wednesday ahead of an upper level trough and cold front. High temperatures will reach their warmest values since December 1 for most locations, ranging from the low 30s across the north to lower 40s along the coast. The shortwave trough will provide lift for snow showers across northern and Central regions. Steadier snow across the higher terrain and far northern Maine could leave a quick coating to inch of snow, with locally higher amounts over the highest SW facing slopes of the Central Highlands and North Woods late Wednesday afternoon into Wednesday evening.

A cold front then moves through later Wednesday night, followed by a ridge of high pressure Thursday morning and return flow Thursday afternoon as the ridge moves eastward and a larger trough digs into the Great Lakes. Another mild day is expected as the return flow overwhelms any brief cold advection during the morning. Mostly clear skies are expected early, with some increasing high clouds late.

LONG TERM /THURSDAY NIGHT THROUGH MONDAY/

Key Messages: * Strong winds are likely with damaging winds possible late Thursday night into Friday, particularly along the coast. Additional strong wind gusts are likely Friday night into Saturday morning. * Rain is expected across the entire area Friday followed by temperatures falling below freezing Friday night.

Thursday night to Friday: A highly amplified upper level trough over the Great Lakes will become neutrally to negatively tilted Thursday night, resulting in a surface low deepening over the Great Lakes into western Quebec. Strong warm advection associated with a south to north oriented low level jet will bring in a maritime air mass over a cold snowpack. This will result in fog forming late Thursday night into Friday, along with a period of moderate to briefly heavy rainfall across the entire forecast area. Rainfall amounts of one half to one inch are most likely, with a small chance of local amounts to around 1.5 inches. Significant snowpack loss is expected Downeast, with less snowpack loss and more compaction for central and northern areas. The snowpack will absorb most of the rainfall, so flooding is not a significant concern. The low level jet will also produce strong to possibly damaging winds, especially along the coast. Further inland, cold snowpack should act to strengthen the surface inversion and limit mixing towards the surface. Astronomical tide cycles are low with a new moon, so coastal flooding is not expected.

Friday Night to Saturday: A cold front will sweep through the area just after sunset Friday evening. There will be plenty of time for surfaces to dry out across southern areas to limit flash freeze concerns. However, over the north there will be less time, generally less than 6 hours, between the end of precipitation and the start of freezing temperatures. The exact details and severity of any flash freeze remain uncertain, but at least some lingering freezing of standing water and slush is going to occur.

Winds shift out of the WNW to NW Friday night and become strong through Saturday morning. Wind gusts to advisory level are possible with gusts to 40 to 50mph, though some model differences remain regarding the strength of the pressure gradient. Higher NBM percentiles were used for the official forecast from Thursday night through 18z Saturday. By Saturday afternoon, winds begin to decrease as the pressure gradient loosens. Wind chills Saturday morning will range from 5 to 10 below across the north, to 5 to 10 above along the coast, with air temperatures generally in the teens north to 20s south.

Saturday night to Monday: Zonal flow sets up for Saturday night into Sunday, leading to modest warm advection and a return to near normal temperatures. A warm front crosses the area Saturday night, leading to a strong chance (50-70 percent) of accumulating snow across the forecast area. Lingering snow showers are possible on Sunday with near normal temperatures favored as a cold front crosses the area. Guidance then favors a trough across New England with multiple embedded shortwaves keeping cold air entrenched and potential for snow showers into early next week.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

NEAR TERM: VFR conditions through the next 24 hours. Winds gradually relax tonight, becoming more westerly, and then more southwesterly tomorrow. Increasing clouds late in the TAF period, but ceilings still remaining VFR through tomorrow night.

SHORT TERM: Wednesday...VFR Downeast terminals, becoming MVFR/IFR in light snow northern terminals. Winds SSW 5-15kts gusts to 20kts.

Wednesday night...Improving to VFR north. Remaining VFR elsewhere. Winds WSW 5-15kts.

Thursday...VFR. Winds S 10 gusting to 20 kts.

Thursday night-Friday...IFR in rain, possibly lower with areas of fog. LLWS Thursday night and Friday morning. Winds S 10-25 kts with gusts to 30kts north and 40kts for BGR and coastal terminals.

Friday night to Saturday...MVFR north, VFR Downeast. Winds NW 15-25kts with gusts to 35kts, decreasing Saturday afternoon.

MARINE

NEAR TERM: Small Craft Advisory over the waters until late tonight. Lull in conditions as winds fall below criteria through tomorrow, before ramping back up to potential Gale conditions over the outer waters Tuesday night. Wave heights will gradually relax back to 5 ft or below late tonight. Winds currently from the NW, shifting to the W tomorrow, and shifting SW by tomorrow night. Light freezing spray possible today into tonight.

SHORT TERM: SW winds remain at Gale force into Wednesday. Winds diminish below gales Wednesday night then below SCA levels Thursday morning before increasing back to gale force from the south Thursday evening. Winds then shift from the west late Friday afternoon, remaining at gale force through early Saturday morning before falling below SCA levels by Saturday night. Seas increase above 5ft late Tuesday night to as high as 12ft over the outer waters Wednesday afternoon. Seas diminish slightly before ramping up again toward 15ft Friday afternoon and remain elevated above 5ft through Saturday evening.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...Small Craft Advisory until 5 AM EST Tuesday for ANZ050>052.