textproduct: Caribou

WHAT HAS CHANGED

-Added slight chance and chance pops for snow showers and squalls today with the highest pops early to mid afternoon across central and eastern areas.

-Increased confidence in significant snowfall possible along Downeast and coastal areas Sunday night into Monday

KEY MESSAGES

1) Snow showers and isolated heavier snow squalls may cause brief whiteout conditions and slick travel today.

2) Frigid Arctic air will surge into the area later today into the coming weekend bringing bitter cold wind chills.

3) Increased confidence in significant winter storm to impact Downeast Maine Sunday night through Monday

DISCUSSION

KEY MESSAGE 1...Snow showers and isolated heavier snow squalls may cause brief whiteout conditions and slick travel today.

KEY MESSAGE 1 DESCRIPTION... Arctic air will begin surging into the area today. The cold air will move in more quickly aloft than at the low levels resulting in some steep lapse rates up to 10K ft and CAPES up to 50 J/KG. A bit of solar heating during the midday may add to the instability. Snow showers will be mostly likely through the early to mid afternoon from the Central Highlands east across east central areas but could occur anywhere. Strong gusty winds being pulled down from aloft may result in blowing snow and isolated brief whiteout conditions. Falling temperatures during and after snow showers and squalls could result in any dampness on the roads freezing and producing slippery conditions. The combination of slippery road surfaces, and poor visibility due to blowing snow, can be especially hazardous due to the potential that a traveler will be unable to see an obstruction ahead until its too late to be able to stop in time, or be unable to stop due to the slippery roads. Any snow showers or squalls should taper off late today as the colder drier air continues to overspread the area.

KEY MESSAGE 2...Frigid Arctic air will surge into the area later today into the coming weekend bringing bitter cold wind chills.

KEY MESSAGE 2 DESCRIPTION... The combination of bitter cold Arctic air and strong gusty winds will produce dangerously cold wind chills tonight into the weekend. By early Saturday morning westerly winds 10 to 15 mph gusting to 25 mph combined with temperatures from the teens below north to the single digits below Downeast will result in wind chills from the 30s below across the north to the 20s below Downeast. The frigid wind chills will continue through the day on Saturday. The extreme cold will bring with it the risk of hypothermia and possible frostbite on unprotected skin.

Similar wind chill values could occur on Saturday night as well, -30 to -40 in the north and west, -30 to -25 in the Central Highlands, and around -25 to -20 in the Bangor and Downeast regions. There is a chance for clearing to occur overnight, and alongside lighter winds, which would cause temperatures to plummet quickly. Highs on Sunday will be around 0 in the north, single digits in Central Highlands, and around 10 around Bangor region to Downeast. Wind chills will improve Sunday night, but not by much. Northern Maine expecting -20 to -15 chills, central Maine around -15 to -10, and Downeast around -10 to -5. A warming trend is expected Monday onwards.

KEY MESSAGE 3...Increased confidence in significant winter storm to impact Downeast Maine Sunday night through Monday

KEY MESSAGE 3 DESCRIPTION... Models continue to show potential for low pressure system moving through the mid-Atlantic this weekend to strengthen over the maritimes. For the past few days, there has been a northerly trend in the models with this low pressure system, bringing the low closer to the mainland when it goes over the Gulf of Maine. Naturally, this increases snowfall across the CWA. There is increased confidence in at least warning level snowfall (at least 6 inches) in the Downeast and coastal regions. Timing of this system seems to generally have precipitation moving in by midnight on Monday, moving from the southwest to the northeast. QPF and PWAT values have been increasing with the strengthening low trend as well, further favoring the possibility of decent snowfall anticipated along the coast. Cold arctic air helps to keep snow ratios generally around 20:1, for light and fluffy snow throughout northern and eastern Maine. Left exit region of an impressive upper level jet provides opportunity for decent lift that could result in periods of heavier snow showers, which could further ramp up snow totals. The main questions to monitor currently are 1) how far north into the Gulf of Maine will this low pressure system go, and in turn 2) how much snow can make it into central and northern Maine? Currently, anticipating at least a few inches to reach central and northern Maine. This will be a storm to monitor as more model runs continue to pick up on the behavior of this low pressure system. Some models do want to have significant snowfall falling everywhere across northern and eastern Maine, but it is too early to be confident in that, as this result is heavily going to depend on the location of the low pressure system. Best confidence is that higher snow totals with be around Downeast and coastal Maine. As a result of this, expect some travel disruptions Sunday night into Monday.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

Today...VFR conditions all sites with the possible exception of a snow shower or isolated snow squall briefly resulting in MVFR or IFR conditions across northern and central areas during the afternoon. Winds W 10 to 15 kt gusting to 25 kt.

Tonight...VFR conditions, possibly dropping to MVFR at times over the far north. W to NW winds 10 to 15 kt gusting to 25 kt.

Saturday...VFR conditions. W to NW winds 10 to 15 kt gusting to 25 kt.

Saturday night through Sunday...VFR. W/NW winds 5 to 10 kts with gusts around 15kts overnight, diminishing to around 5 kts Sunday.

Sunday night through Monday...Becoming MVFR and likely IFR at southern terminals with snow. VFR/MVFR and possibly IFR Monday at northern terminals with snow. N/NE winds increasing to 5 to 10 kts.

Monday night through Tuesday...IFR/MVFR conditions improve to VFR/MVFR. N winds 5 to 10 kts Monday night, becoming W and 10 to 15 kts Tuesday.

MARINE

A gale warning will be up today and tonight for W to NW winds gusting up to 40 kt. Winds will drop below gale on Saturday. A heavy freezing spray warning will be up from late this evening through Saturday for heavy ice riming conditions in the wind and extreme cold.

Small Craft conditions anticipated Saturday night into Sunday, when winds ramp back up to Gale force on Monday morning. Heavy freezing spray warning continues into Sunday morning, and then relaxes back down to light freezing spray on Sunday. Could become moderate again by Sunday night into Monday. Winds from the NW Saturday night night, shifting to the northeast by Sunday night. Chance for snowfall Sunday night into Monday.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Extreme Cold Warning from 1 AM to 10 AM EST Saturday for MEZ001>006-010-011-031-032. Cold Weather Advisory from 1 AM to 10 AM EST Saturday for MEZ015>017-029-030. MARINE...Gale Warning until 1 PM EST Saturday for ANZ050-051. Heavy Freezing Spray Warning from 10 PM this evening to 10 AM EST Sunday for ANZ050>052. Gale Warning from 6 PM this evening to 7 AM EST Saturday for ANZ052.