textproduct: Caribou

WHAT HAS CHANGED

Update to aviation discussion.

Small Craft Advisory reissued for tonight through Saturday.

KEY MESSAGES

1) Temperatures rise to nearly 10 degrees above normal Saturday before an Arctic front moves into the area late Sat afternoon. Snow and rain showers occurring ahead of the front, with squalls possible with any snow showers, reducing visibilities.

2) Bitter cold Arctic air will overspread the region behind the cold front Saturday night. This will result in frigid conditions from Saturday night into Monday. The coldest temperatures will be from late Sunday night into Monday morning bringing with it the risk of frostbite and hypothermia.

DISCUSSION

KEY MESSAGE 1... Temperatures rise to nearly 10 degrees above normal Saturday before an Arctic front moves into the area late Sat afternoon. Snow and rain showers occurring ahead of the front, with squalls possible with any snow showers.

KEY MESSAGE 1 DESCRIPTION... A strong low level jet will develop Saturday morning as sfc low moves through nrn Quebec. A tight pressure gradient develops between 980mb sfc low and 1030mb hipres over the Canadian Maritimes during the day. Southwesterly low-level jet of 50-60 kts will allow sfc temps to warm to around 40 degrees during the day. Winds will frequently gust to 30-40mph, especially at higher elevations.

An Arctic front will be approaching from the northwest with a pre-frontal trof moving through in the afternoon. Precipitation likely to develop ahead of the initial trof, most likely in the form of rain showers, though may see a mix with snow showers over the far northwest as Arctic front moves in toward 00z. Steep low-level lapse rates and plenty of sfc instability looks to be enough to result in potential for snow squalls but how quickly temps can drop to change rain over to snow is more in question that previously thought.

KEY MESSAGE 2...Bitter cold Arctic air will overspread the region behind the cold front Saturday night. This will result in frigid conditions from Saturday night into Monday. The coldest temperatures will be from late Sunday night into Monday morning bringing with it the risk of frostbite and hypothermia.

KEY MESSAGE 2 DESCRIPTION... The cold front will push off the coast Saturday evening as Arctic high pressure begins to build in from the west. Cold Arctic air will filter into the region Saturday night with lows by Sunday morning from near zero over the far northwest to the low 20s Downeast. Sunday will remain bitter cold over the north with highs only in the low to mid teens. A weather disturbance crossing the south may bring some light snow to southern areas. Otherwise, the south will not be as cold with highs near 30 along the coast. Arctic high pressure will then continue to build in Sunday night with frigid temperatures expected across the entire area. Lows by Monday morning will range from the mid teens below zero northwest to near zero Downeast and wind chills will range from the mid 20s below in some northern spots to around ten below Downeast. This could result in the risk of hypothermia and frostbite. Anyone venturing outdoors Monday morning is advised to dress in layers and protect hands and face. Temperatures Monday will remain very cold with highs only from the low teens north to around 20 downeast which will be around 15 degrees below normal across the area.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

Today...May see brief MVFR cigs at northern Aroostook terminals early as low stratus moves south through the area. VFR likely after 13z this morning at all terminals. W winds 5kts becoming south 5-10kts late tonight.

Tonight...VFR early diminishing to MVFR cigs after 07z Aroostook terminals. S 5-10kts.

Saturday...Mainly VFR Downeast terminals with MVFR/IFR Aroostook terminals. SW 10-20kts, gusting to 25kts. LLWS at all terminals in the afternoon.

Saturday night...VFR north. MVFR becoming VFR south. NW wind around 5 kt.

Sunday...VFR north. MVFR south, possibly dropping briefly to IFR at times in light snow. NW wind around 5 to 10 kt.

Sunday night...VFR north. MVFR becoming VFR south. NW wind 5 to 10 kt.

Monday...VFR except possibly briefly lowering to MVFR at times over the far north. W wind around 5 kt.

Monday night...VFR, possibly lowering to MVFR north late. SW wind around 5 kt.

Tuesday...MVFR to IFR north. VFR south. SW wind around 10 kt.

MARINE

Seas expected to rise above 5ft late this evening. By Saturday afternoon seas increase to between 5 to 7 feet in southerly swell. Southwesterly winds increase to small craft levels early Saturday morning and remain elevated through the day.

Winds will drop below SCA Saturday evening then increase back to an SCA late Sunday with a strong SCA or gale likely Sunday night. Winds will drop below SCA Sunday. Moderate freezing spray is likely Sunday night into Monday morning. A SCA may be needed again late Tuesday into Wednesday morning. Seas will be up to 6 ft Saturday evening dropping to around 4 ft by Sunday morning. Seas will remain around 4 ft through Monday morning then drop to around 3 ft from late Monday into Tuesday.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...Small Craft Advisory until 7 AM EST this morning for ANZ050- 051. Small Craft Advisory from 8 PM this evening to 1 AM EST Sunday for ANZ050-051. Small Craft Advisory from 4 AM to 7 PM EST Saturday for ANZ052.