Small Craft Advisory 6, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
1225 PM AKST Sun Jan 15 2017

.DISCUSSION...
What a difference cloud cover makes in an arctic air mass, about
a 40 degree difference in Fairbanks as light snow and clouds and 5
degrees above yesterday departed overnight leaving mostly clear
skies and a balmy 35 below this morning. Fortunately more clouds
and snow are on the way for the central and eastern interior and
will bring a short reprieve to the cold temperatures before
clearing skies bring back more cold temperatures this later this week.

The 12z model suite initialized well against the 12z analysis and
verified well against the 18z analysis. Model spread is minimal
in the short and mid range and is reasonable in the extended
range. Subtle differences in timing and position of cloud cover
and light snow will have large impacts on local temperatures with
low confidence on temperatures beyond 24 to 36 hours based on poor
performance of model timing on shortwave features moving clouds
in and out of a particular area. Long range models continue to
indicate the cold air mass remaining over interior Alaska through
next weekend.

Aloft at 500 HPA the very cold long wave trough with a 490 DAM
anchoring low over the central Brooks Range with axis from
Demarcation Point to Nunivak Island remains in place through
Monday and then realigns with another cold low dropping south
through the Bering Strait and reinforces the cold air over the
western interior as the anchoring low over the central Brooks
Range pulls north and east to be near Banks Island Monday. Slight
warming aloft pushes into the southeast interior as weak ridging
occurs ahead of the upper level low dropping south of the the high
arctic with 1000 to 500 mb thickness values rising above 500 DM
at Fairbanks Monday and then dropping to around 492 DM to 486 DM
Wednesday and Thursday. The cold airmass remains over central
Alaska with 1000 to 500 mb thickness values around 492 and 850 mb
temperatures around 30 below through the end of the week. This is
a very cold air mass and temperatures will drop rapidly with any
prolonged period of clearing skies and will rise dramatically with
clouds moving into an area.

On the surface a 965 mb low near 55N and 150W will continue to
move north and east and will be located near Prince William Sound
Monday morning as a 968 mb low. A front moving north and west
around the low moves into the southeast interior tonight and into
the central interior Monday and will bring advisory level snow
over the fortymile country and eastern Alaska Range beginning
tonight and continuing through Monday. Light snow will move west
of Fairbanks to near Tanana and Bettles where 1 to 4 inches of
snow is expected and will be heaviest just east of Fairbanks. As
the low moves into the southern Yukon light snow will move north
into the eastern Brooks Range Monday night and Tuesday and the
eastern north slope Tuesday. Skies begin to scatter out Wednesday
over the southern interior and combined with light winds will
provide for strong radiational cooling and will likely take
temperatures into the 40s below Wednesday, Thursday and Friday
over the interior.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory for AKZ204-AKZ213.

Heavy Freezing Spray Warning for PKZ210.

Small Craft Advisory for PKZ210.

Brisk Wind Advisory for PKZ245.
&&

CCC JAN 17

Special Weather Statement
National Weather Service Fairbanks AK
950 PM AKST Sun Jan 15 2017

AKZ218>226-170000-
Southeastern Brooks Range-Upper Koyukuk Valley-
Yukon Flats and Surrounding Uplands-Central Interior-
Middle Tanana Valley-Deltana and Tanana Flats-
Upper Tanana Valley and the Fortymile Country-Denali-
Eastern Alaska Range-
Including Arctic Village, Wiseman, Coldfoot, Chandalar DOT Camp,
Iniakuk Lake, Allakaket, Hughes, Bettles, Caribou Mountain,
Gobblers Knob, Fort Yukon, Venetie, Central, Circle,
Stevens Village, Beaver, Chalkyitsik, Birch Creek,
Circle Hot Springs, Eagle Summit, Twelvemile Summit, Nenana,
Anderson, Tanana, Minto, Manley Hot Springs, Rampart,
Lake Minchumina, Livengood, Fairbanks, Fort Wainwright,
Eielson AFB, Ester, North Pole, Moose Creek, Two Rivers, Fox,
Chatanika, Chena Hot Springs, Sourdough Camp, Salcha,
Delta Junction, Fort Greely, Harding/Birch Lake, Dry Creek,
Dot Lake, Healy Lake, Tok, Tanacross, Eagle, Tetlin, Northway,
Alcan, Chicken, Boundary, Healy, Denali National Park,
Carlo Creek, Kantishna, Mentasta Lake, Black Rapids,
Donnelly Dome, Trims DOT Camp, Eagle Trail, and Mineral Lake
950 PM AKST Sun Jan 15 2017

...SNOW THEN PERIODS OF COLD TEMPERATURES THIS WEEK...

A LOW PRESSURE SYSTEM MOVING INTO THE INTERIOR FROM THE SOUTHEAST
WILL ARRIVE OVERNIGHT TONIGHT. SNOWFALL TOTALS OF 4 TO 7 INCHES
ARE EXPECTED SOUTH OF A LINE FROM FORT YUKON TO NENANA BY LATE
MONDAY NIGHT...WITH AROUND 1 TO 3 INCHES EXPECTED ALONG AND NORTH
OF THIS LINE. SNOWFALL TOTALS WILL BE HIGHER IN THE EASTERN
ALASKA RANGE WITH AROUND ONE FOOT OF SNOW FALLING IN THE
MOUNTAINS EAST OF THE TOK CUTOFF.

FOLLOWING THE EXIT OF THE SNOW TOMORROW NIGHT...CLOUD COVER IS
EXPECTED TO DECREASE FROM SOUTH TO NORTH INTO TUESDAY... AND WILL
REMAIN VARIABLE FOR THE INTERIOR THROUGHOUT THE UPCOMING WEEK.
FOR AREAS THAT EXPERIENCE CLEARING FOR AROUND 12 CONSECUTIVE HOURS
OR MORE...TEMPERATURES ARE EXPECTED TO DROP AS LOW AS 35 TO 45
BELOW FOR INTERIOR VALLEYS...INCLUDING IN AND AROUND FAIRBANKS. A
LARGE AMOUNT OF UNCERTAINTY REMAINS ON THE EXACT TIMING OF THE
COLDEST PERIODS...BUT CONFIDENCE IS HIGH THAT MOST VALLEY
LOCATIONS WILL EXPERIENCE ONE OR MORE PERIODS OF VERY COLD
TEMPERATURES THIS WEEK. PLEASE KEEP UP TO DATE ON THE LATEST
FORECASTS...AS SEVERAL CHANGES IN THE TEMPERATURE AND CLOUD
FORECASTS ARE EXPECTED THROUGHOUT THE UPCOMING WORK WEEK.
TEMPERATURES WILL GRADUALLY MODERATE NEXT WEEKEND.