textproduct: Caribou

SYNOPSIS

High pressure builds across the region Friday into Saturday. A cold front crosses the region Sunday. High pressure builds toward the region Monday and crosses the region Tuesday. Low pressure could cross the region Wednesday.

NEAR TERM /THROUGH FRIDAY NIGHT/

Key Messages: * Frigid temperatures tonight, gusty W-NW winds * Snow Squalls end this evening

Discussion... The arctic cold front is pushing SE across the central half of the CWA with heavy snow showers. Instability has been lacking today preventing these snow showers from reaching squall criteria. However, cannot rule out dangerous travel conditions through this evening till the cold front can clear the Downeast coast. Latest timing shows that occurring between 3PM and 5PM with most snow showers ending across the area. Temperatures are falling behind this front but generally 2-5 degrees and slow falls with us getting much closer to sunset this time of year.

Secondary cold front which is the big push of arctic air will be pushing down over the area this late afternoon into the evening. The air mass that is arriving in Maine originated in Siberia Russia around November 26th. NOAA Hysplit modeling shows the air mass tracked down over the North Pole into Central Canada and then now arriving in Maine. Cannot rule out some isolated snow showers overnight across the north thanks to NW winds providing a band of Laurentian snow showers streaming down from the St. Lawrence River Valley of Quebec. This is typically hardly modeled correct in strong NW flow when the St. Lawrence River is still open providing significant amount of moisture into the low levels.

Hi-Res modeled soundings shows the well mixed boundary layer this evening into the overnight hours with strong cold air advection. Expecting W-NW winds to become gusty with gusts 25-35mph and some higher gusts possible over the higher terrain. These gusts combined with air temperatures falling below zero for much of Northern Maine & Central Highlands will send wind chills deeply below zero. Wind chills tonight across the Moosehead Region, North Woods and all of Northern & Northeast Aroostook County expected to drop to between -30F and -25F so have continued the Cold Weather Advisory from 9PM tonight till 8AM Friday. Have opted to expand it to NE Aroostook in this update with increasing confidence in wind gusts. Air temperatures outside of the advisory will be running from -5F north to +5F at the coast. Wind chills will drop into the -18F to -10F range tonight.

In addition to the frigid temperatures gusty winds will lead to areas of blowing snow tonight thanks to fresh snowfall. Localized whiteouts and dangerous driving conditions in the open areas of Aroostook and N. Penobscot counties. This could impact such roadways but not limited too; Routes 1, 1A, 2, 10, 11, 89, 161, 163, 167 and 212. Additional areas of blowing snow across any open areas of the Central Highlands especially along Route 6 to Moosehead/Greenville region.

Friday will feature surface high pressure drifting east over Cape Cod. Winds will relax and slowly shift SW. Air temperatures will remain cold with highs in the low teens north, mid to upper teens Central Highlands to Bangor Region and low 20s Downeast. Any winds will keep wind chills below zero across the north and single digits above zero for the southern zones. Friday night air temperatures will fall back around 0F across the north with 0-10F across the Central Highlands to Bangor region and 10-15F for the Downeast coast.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/

High pressure exits across the Maritimes Saturday with a warm front then approaching late. Expect partly sunny skies early Saturday, with clouds then increasing along with isolated/scattered snow showers. A strong cold front will cross the region Saturday night through early Sunday. Expect mostly cloudy skies along with scattered snow showers across northern areas Saturday night. Across Downeast areas, expect mostly cloudy skies with isolated/scattered snow showers early then partly cloudy. High pressure builds toward the region Sunday with generally partly sunny skies, though could also have isolated snow showers early across the north and mountains. Another system could begin to approach from the west later Sunday night with a chance of snow or snow showers, though uncertainty still exists. Temperatures will be at below normal levels Saturday/Sunday.

LONG TERM /MONDAY THROUGH THURSDAY/

Could have a chance of snow showers or snow with the system Monday, though uncertainty still exists. A more active pattern is possible Tuesday through Thursday. An upper low should remain in the vicinity of northern Quebec province Tuesday through Thursday. A series of difficult to time disturbances should rotate around the upper low each of which which could support a possible surface low. One system is possible later Tuesday into Wednesday, with another possible system later Wednesday into Thursday. The strength, track and timing of these systems is still uncertain. Precipitation chances, types and amounts will be dependent on how these systems eventually develop. Much below normal level temperatures are expected Monday/Tuesday, with slightly below normal level temperatures Wednesday/Thursday.

AVIATION /19Z THURSDAY THROUGH TUESDAY/

NEAR TERM: Northern Terms...VFR/MVFR cigs and brief MVFR vsby possible due to VCSH/-SHSN this evening. Turning VFR. W-NW winds increasing to 10-15kt and gusts 20-35kt. LLWS likely late. Tomorrow will feature VFR. Winds relaxing and shifting W-SW 5-15kt in the afternoon.

Southern Terms...VFR. Brief MVFR cigs/vsby due to -SHSN through sunset. Then VFR. W-NW winds increasing 10-15kt with gusts 25-35kt. LLWS likely late. Tomorrow will feature VFR, winds relaxing and shifting W-SW 5-15kt in the afternoon.

SHORT TERM:

Saturday...VFR early, then VFR/MVFR. Variable winds 5 to 10 knots, becoming south/southeast.

Saturday night...VFR/MVFR. Isolated/scattered snow showers. Variable winds 5 to 10 knots, becoming west/northwest 10 to 15 knots.

Sunday...Isolated early snow showers north. Otherwise, VFR/MVFR. West/northwest 10 to 15 knots with gusts 20 to 25 knots.

Sunday night...VFR/MVFR early, then MVFR/IFR. A slight chance/chance of snow. North/northwest winds 10 to 15 knots.

Monday...VFR/MVFR, occasional IFR. A slight chance/chance of snow. North/northwest winds 10 to 15 knots with gusts 20 to 25 knots.

Monday night...VFR/MVFR. West/northwest winds 10 to 15 knots.

Tuesday...VFR early, then VFR/MVFR with a slight chance of snow showers. West/southwest winds 10 to 15 knots, becoming south.

MARINE

NEAR TERM: Gale Warning in effect through 7AM Friday for all of the waters out 25nm. NW winds tonight 25-35kt and gusts up to 45kt. Seas 7-10ft over the coastal waters and 3-5ft for the intra-coastal waters. Winds/seas will fall below SCA criteria between 7-10AM Friday morning. Winds shifting W and relaxing well below SCA levels Friday evening into the overnight hours to Saturday early AM.

SHORT TERM: Conditions below small craft advisory levels Saturday/Saturday night. Small craft advisory conditions possible Sunday/Sunday night. Isolated/scattered rain and snow showers Saturday into Saturday night.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Cold Weather Advisory from 9 PM this evening to 8 AM EST Friday for MEZ001>004-010. MARINE...Gale Warning until 7 AM EST Friday for ANZ050>052.