textproduct: Caribou

WHAT HAS CHANGED

-Increased confidence in potential for snow squalls on Friday

-Added potential for blowing snow in the north on Friday

KEY MESSAGES

1) Frigid arctic air brings extremely dangerous wind chills this weekend and potential squalls.

2) Light snow Wednesday night, mostly Downeast, will result in some slippery and snow covered roads Thursday morning.

DISCUSSION

KEY MESSAGE 1...Frigid arctic air brings extremely dangerous wind chills this weekend and potential squalls.

On Friday, occluding low pressure system continues its journey eastward through Maine. In its wake, an arctic air mass will settle over the region this weekend, bringing bitter wind chills throughout northern and eastern Maine. Temperatures begin to drop on Friday, with overnight lows around 10 in the north, and just below 0 Downeast. Gusty winds forecast with strong pressure gradient and mid-to-upper level jet rolling through the region, resulting in wind chills around -30 to -40 in the north, around -30 in Central Highlands, and around -25 to -20 in the Bangor and Downeast regions. High temperatures on Saturday will be just below 0 in the north, and the single digits Central Highlands and Downeast. Similar wind chill values could occur on Saturday as well, -30 to -40 in the north, -30 to -25 in the Central Highlands, and around -25 to -20 in the Bangor and Downeast regions. 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 -30 to -25 chills, central Maine around -20 to -10, and Downeast around -10. Exposure to these frigid temperatures can quickly result in frostbite and hypothermia.

Added in a chance for some blowing snow on Friday in the north, as any recently fallen fluffy snow could loft with the high winds, which could reduce visibility and cause issues with travel.

Additionally, arctic front passage on Friday brings a chance for some snow showers, and a potential for snow squalls in northern and eastern Maine. Currently, there is uncertainty in the exact location these squalls could develop, but there is some favorable instability and lift that could cause some bursts of snow Friday afternoon into evening. Nonzero CAPE, and high snow squall parameter, omega, low-level lapse rates, and moisture all indicate that squalls could develop, which could impact travel. Continue to monitor the forecast for updates as confidence increases, once as models get a better handle on the environment.

KEY MESSAGE 2... Light snow Wednesday night, mostly Downeast, will result in some slippery and snow covered roads Thursday morning.

Low pressure will track from Ontario into Quebec Wednesday night. An occlusion will extend southeast from this low to a weak triple point along the Maine coast. The occlusion will spread light snow across the area overnight generally ranging from around a half inch across the north, to 2 to 4 inches Downeast where the triple point low will enhance snowfall just a bit. Temperatures overnight will range from the low to mid teens north to the 20s Downeast with some low 30s along the coast. This will allow any snow to accumulate resulting in some messy roads Thursday morning.

The occlusion will lift out to the northeast on Thursday. However, a weak weather disturbance crossing the north may combine with some steep lapse rates to cause snow showers to persist over the north. An isolated snow squall is possible over the north Thursday afternoon which could coat roads and possibly cause a brief abrupt drop in visibility in some areas.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

Today...VFR except occasional MVFR over the far north. SW wind 5 to 10 kt.

Tonight...MVFR across the north dropping to IFR after midnight in light snow. VFR/MVFR over the south dropping to IFR late this evening in light snow. Winds SW around 10 kt dropping to 5 kt late.

Thursday...IFR improving to VFR south and MVFR north. Risk of isolated snow showers/squalls in the afternoon north which could cause brief IFR conditions. Winds S around 5 kt becoming SW 5 to 10 kt.

Thursday night...VFR/MVFR with a slight chance of snow showers in the north. VFR Downeast. Southwest/west winds 10 to 15 knots.

Friday...Variable conditions with any snow showers. Slight chance for blowing snow at northern terminals. Slight chance for snow squalls during the afternoon/evening on Friday at all terminals. Southwest/west winds 10 to 15 knots with gusts up to 20 to 25 knots.

Friday night through Saturday...VFR/MVFR north. VFR Downeast. West/northwest winds 10 to 15 knots with gusts up to 25 to 30 knots.

Saturday night through Sunday...VFR at all terminals. West/northwest winds 10 to 15 knots with gusts up to around 20 knots Saturday night. West/northwest winds 10 to 15 knots Sunday.

MARINE

A SCA will be needed today through Thursday for SW winds gusting up to 30 kt with a few gusts to 35 kt over the offshore waters. Some light freezing spray is likely Today. Seas up to 5 ft today then 8 ft tonight into Thursday.

Winds expected to ramp up to potential Gale conditions Friday through the weekend, with outer water seas reaching up to 7-9 ft. Light freezing spray Friday, becoming moderate freezing spray on Friday night, and then high freezing spray on early Saturday. Relaxes back down to moderate freezing spray on Saturday afternoon, and light on Sunday. Winds from the west Thursday night, shifting to the northwest by Friday night. Chance for snow showers on Friday.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...Small Craft Advisory until 7 PM EST Thursday for ANZ050>052.