textproduct: Caribou

WHAT HAS CHANGED

- Increased confidence in extremely cold weather this weekend.

KEY MESSAGES

1) Very cold wind chills Tuesday into Tuesday night causing hypothermia or frostbite to exposed skin.

2) Artic air late week through the weekend brings the coldest air of the season along with dangerous wind chills.

3) Light snow Wednesday night into Thursday.

DISCUSSION

KEY MESSAGE 1... Very cold wind chills Tuesday into Tuesday night causing hypothermia or frostbite to exposed skin.

KEY MESSAGE 1 DESCRIPTION... The exiting low pressure system will move off to the NE into the Maritimes tonight into Tuesday. The approaching surface will cause the pressure gradients to tighten which will create gusty WSW winds. In addition, the upper level trof will move into the region bringing a very cold airmass into the area. The 925mb model temps show around -20C in the north and -14C in the south. Since the upper air model soundings show a mixing layer above 925mb, these cold temps will mix down Tuesday and Tuesday night. By the evening of Tuesday, temps will decrease into the single digits above zero with wind chills in the teens below zero. The surface ridge is not expected to move across the region until after midnight, thus winds will remain breezy into the night. Once the ridge moves in, winds will decrease towards Wednesday morning. Though the winds will be lower, winds chills will reach into the 20s below zero. Concerns will be for Wednesday morning commuters being outside for an extended period of time.

KEY MESSAGE 2... Artic air late week through the weekend brings the coldest air of the season along with dangerous wind chills.

KEY MESSAGE 2 DESCRIPTION... Arctic air will spill across the region Friday then persist through the weekend into early next week. Much below normal level temperatures are expected Friday through Monday. High temperatures Friday will range from around 10 to around 15 north, to the lower to mid 20s Downeast. Low temperatures Friday night will range from around 10 to 15 below zero north, to around zero to 5 below Downeast. High temperatures Saturday will range from around zero to 5 below north, to 5 to 10 Downeast. Low temperatures Saturday night will generally range from 15 to 20 below zero north, to 5 to 10 below zero Downeast. High temperatures Sunday will range from around zero north, to 5 to 10 Downeast. Low temperatures Sunday night will range from 10 to 15 below zero north, to around zero to 5 below Downeast. High temperatures Monday will range from around zero to 5 above north, to 10 to 15 Downeast. However, wind chill values will be much lower. The pressure gradient between intensifying low pressure moving from the Gulf of Saint Lawrence to Labrador and strong Arctic high pressure to the west will support gusty winds Friday into Monday. These winds, together with the very cold temperatures, will produce dangerous wind chills Friday into Monday. Wind chill temperatures later Friday into Monday will generally range from around 25 below to 40 below zero across northern areas, with around 10 below to around 25 below zero Downeast.

KEY MESSAGE 3... Light snow Wednesday night into Thursday.

KEY MESSAGE 3 DESCRIPTION... An intensifying clipper system will approach western Quebec province Wednesday night, then track northwest of Maine Thursday drawing an occluded front across the forecast area. Weak low pressure could try to develop along the occlusion. Snow will accompany this system. Snow totals are still uncertain. However, current indications only support light accumulations with the greatest accumulations across Downeast areas. Snow will taper to snow showers Thursday night.

AVIATION /19Z MONDAY THROUGH SATURDAY/

Mainly VFR conditions this evening with brief MVFR cigs in the south. By tonight, south terminals improve to VFR while north terminals will see brief MVFR cigs. By Tuesday and Tuesday night, VFR conditions for all terminals. Light SW winds this evening increase to 15-20 kts with gusts up to 30 kts tonight into Tuesday. By Tuesday night, WSW winds 5-10 kts.

Wednesday...VFR. Southwest/south winds 10 to 15 knots.

Wednesday night...VFR early. MVFR/IFR late with a chance of snow. South/southeast winds 5 to 10 knots.

Thursday...MVFR/IFR, occasional LIFR. Snow likely. South/southwest winds 10 to 15 knots.

Thursday night...MVFR/IFR early. VFR/MVFR late. Snow tapering to snow showers. Southwest/west winds 10 to 15 knots with gusts up to 20 knots.

Friday...VFR/MVFR. West winds 10 to 15 knots with gusts up to 20 to 25 knots.

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

MARINE

A Gale Warning begins tonight, which will lead to light freezing spray through the day on Tuesday. Gales likely to continue through the day on Tuesday while seas increase to 6 to 11 ft. The intracoastal waters may see gusts approach gale force and could briefly reach 35 kts, but otherwise conditions are likely to be strong SCA level Tuesday. The Gale warning will continue into Tuesday night with a possible freezing spray advisory needed.

Small craft advisory conditions are expected Wednesday. Gale conditions are then possible Wednesday night into Thursday night. Small craft advisory conditions, along with occasional gale conditions, will occur across the waters Friday through the weekend. Snow/rain expected across the waters Wednesday night into Thursday. Light freezing spray early Wednesday. Freezing spray of varying intensities then expected Friday through the weekend with Arctic air crossing the waters.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...Gale Warning from 7 PM this evening to 1 AM EST Wednesday for ANZ050-051. Small Craft Advisory from 7 PM this evening to 1 AM EST Wednesday for ANZ052.