Wind Chill Advisory 4, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
454 AM AKST Fri Jan 19 2018

.DISCUSSION...
Snow, blowing snow, low wind chill values and deep cold on tap as
winter returns to northern Alaska.

The 00z model package initialized well against the 00z surface
analysis and verified well against the 06z surface analysis. Model
spread remains minimal in the the short range and is reasonable
in the mid range. Model spread remains large in the extended range
with over 400 mile differences on the position of large and cold
upper level low and attending trough axis by wednesday of next
week. The large spread in the position of these features will have
a significant impact on sensible weather especially over the
western and central interior where cloud cover or lack there of
will moderate temperatures keeping minimum temperatures in the 20s
and 30s below or the lack of clouds will allow temperatures to
fall into the 30s and 40s below. Opted to take middle of the road
solution at this time with cloud cover and temperatures in the
long range.

Ongoing blizzard on the eastern North Slope expected to continue
into Saturday as cold arctic high pressure builds over the
western North Slope and a low moving north over the McKenzie
Delta increases the gradient to produce 60 mph wind gusts over the
eastern North Slope. Winter Weather Advisories for snow and
blowing snow on the north slope have been updated and extended to
include low wind chill values to 55 below zero as a much colder
airmass from Siberia moves south and east over the western north
slope and western interior today and over the rest of the north
slope tonight and Saturday as well as the central interior
Saturday night and Sunday. Periods of light snow are expected to
continue along a stalled front over the central interior with
generally 1 to 2 inches of snow expected through tonight and again
on Saturday as various weak upper level waves interact with the
stalled frontal system. Additional light snow is expected over the
interior as the cold airmass moves south and east and interacts
with the stalled front and eventually pushes the front into the
eastern interior.

Much colder temperatures are expected to move south and east out
of Siberia and over the western North Slope, the west coast and
western interior today, and over the rest of the North Slope and
central interior Saturday and Saturday night. The 850 mb
temperature was around 8 below on the 12z sounding over Fairbanks
this morning. 850 mb temperatures will continue to fall over the
next several days with 17 below expected Saturday morning and 23
below at 850 mb expected Sunday morning and around 20 below
expected monday morning. Model differences on the position of the
core of the cold airmass results in 850 mb temperatures between
16 below and 26 below by Wednesday of next week over Fairbanks.
850 mb temperatures in this range and combined with 1000 mb to 500
mb thickness values in the 495 dm to 492 dm range would support
30s and 40s below with a lack of clouds or in the 20s to 30s below
with clouds. The models differ on how long the cold airmass
remains over the interior with the Canadian and ECMWF having the
cold air retreat to the west as warmer air moves north into the
central and eastern interior while the GFS keep the cold airmass
entrenched over the interior through next weekend. Continue to
monitor.

Coastal Hazard Potential Days 3 and 4...None.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Blizzard Warning for AKZ204.

Winter Weather Advisory for AKZ201-AKZ202-AKZ203-AKZ206-AKZ218.

Heavy Freezing Spray Warning for PKZ210.

Small Craft Advisory for PKZ210.

Gale Warning for PKZ245.

Brisk Wind Advisory for PKZ215-PKZ230-PKZ235-PKZ240.
&&

CCC JAN 18