textproduct: Caribou

WHAT HAS CHANGED

- Updated aviation section below to reflect 00Z TAFs

- Raised precip amounts and chances during the day Wednesday and Thursday

- Added isolated flurries during the day on Wednesday outside of main snow shower threat

KEY MESSAGES

1) Gusty winds, blowing snow, and cold wind chills expected over the weekend, with possible snowfall.

2) Two shots at minor snow accumulation during the day both Wednesday and Thursday.

DISCUSSION

KEY MESSAGE 1... Gusty winds, blowing snow, and cold wind chills expected over the weekend, with possible snowfall.

KEY MESSAGE 1 DESCRIPTION... Model agreement is still poor for this weekend and not any better in the last 24 hours. In particular, they disagree with the evolution of a digging strong upper trough from the northwest and how it evolves or cuts off over the general region. Many models even have several strong upper level low pressures rotating around each other cyclonically over the whole Northeast US and Canadian Maritime region.

What We Are More Confident In... -Dangerous Wind Chills This Weekend: We are confident in Arctic air moving in sometime Friday night or Saturday. Though there is some uncertainty in when exactly the cold air gets here and just how cold it gets, there is confidence in wind chills at least being 15-20 below zero Saturday night through Sunday night. Wind chills getting to cold weather advisory criteria appear likely at some point. Extreme cold warning criteria appears unlikely but not out of the question. -Gusty Winds: After the Arctic air arrives, persistent northwest winds set up all the way through Monday. Gusts to 30 mph appear likely for most places, with about a 50 percent chance of gusts topping out at 40 mph or greater sometime late Saturday through Sunday. These winds should not be strong enough to lead to any damage, but will exacerbate wind chills (discussed in bullet above), and make for blowing snow (discussed in below bullet). -Blowing Snow: The third element we are pretty confident in is blowing snow. Just how much blowing snow occurs depends on whether or not any new snow falls, but even without snow, the winds will be strong enough and the snowpack blowable enough to where blowing snow should result. We put in patchy blowing snow for the forecast for now, though may need to hit harder if there's snowfall too.

What We Are Less Confident In... -Snowfall: There has been a general trend in the models toward less snowfall for the weekend. If any occurs, it appears it would more likely be on Saturday than Sunday. Many models have the approaching upper level cutting off too far south/west to give us much snow. Many of the models that do still give us snow hint at an inverted trough/nor'lun setup that would hit the coast somewhere from MDI southwest. That said, there are still a few (less than 20 percent) of solutions that bring heavy snow further north to the rest of the area Saturday into Sunday. The much more likely outcome though is minor (less than 2 inches) of snow for the weekend.

Winds start to ease later on Monday and especially on Tuesday as high pressure builds in from the west. Temperatures also begin to become less cold.

KEY MESSAGE 2... Two shots at minor snow accumulation during the day both Wednesday and Thursday.

KEY MESSAGE 2 DESCRIPTION... Wednesday: A vort max will cross the region on Wednesday, providing enough instability for some snow showers to develop through the day. Most of these snow showers will be confined to the Central Highlands and through Downeast Maine, with light accumulations possible. The greatest chance for snowfall will be along coastal Washington county, where forcing and moisture will be greatest. Overall not expecting much more than 1 to 2 inches of snow at most across the area, though local terrain effects could lead to localized amounts greater than 2 inches around the Eastport area.

Thursday: During the day Thursday, another upper level shortwave in northwest flow brings a chance of snow showers areawide, and likely snow showers to the far north. This is a pretty weak system, so we are looking at about 1 inch of snow tops, with the greater threat of this occurring in the north. This will be a fluffy, low-density snow. Not much wind (5-10 mph) associated with the snow. Minor travel difficulties are possible. Went much higher than NBM for PoPs/QPF for Thursday.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

Tonight through Wednesday night...Confidence has increased that conditions will deteriorate to MVFR 07z to 10z in lowering ceilings at all terminals. Moderate confidence in IFR ceilings at the Aroostook county terminals 10z to 16z Wednesday.

MVFR/VFR ceilings expected after 18z Wednesday with similar conditions persisting through Wednesday night.

Light and variable wind tonight through Wednesday morning, then light N to NW wind Wednesday afternoon and Wednesday night.

Thursday...VFR/MVFR, with best chance of MVFR in the north. NW wind 5-10 kts. Light snow showers.

Thursday night and Friday...VFR/MVFR. WNW 5 kts becoming SSW.

Friday Night and Saturday...Very low confidence, but potential for IFR or worse late Friday night into Saturday with snow. Variable winds 10 kts or less becoming NW potentially gusting over 25 kts by late Saturday.

Saturday Night and Sunday...Mainly MVFR north and VFR south, but low confidence. NW winds around 15 kts with gusts around 30 kts.

MARINE

Winds and seas are expected to remain below small craft advisory levels tonight through Wednesday night. Wind gusts on the coastal waters may approach 20 to 25 kts late Wednesday into Wednesday evening as snow showers move through, but then winds will diminish once more. Light freezing spray possible Wednesday night.

Saturday afternoon to Sunday, NW wind when gales appear a near certainty, with about a 50 percent chance of storm force winds. Freezing spray is very likely to be moderate to heavy, with the best chance of heavy freezing spray coming Saturday night.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...None.