Scientific Forecaster Discussion
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
631 am akst Wednesday Dec 4 2013
a massive North Pacific ridge extending northwest across Alaska
will persist through the upcoming weekend. A weak short wave
moving east across the top of the ridge over the North Slope will
move into Canada late today. This feature is causing some brisk
southwest winds and blowing snow over the eastern Arctic zones for
which winter weather advisories are posted...but conditions will
improve later this morning and this afternoon.
A moderate southerly flow on the front side of the ridge is
pushing north over western Alaska and will spread precipitation
north today and tonight. Most of it...from the Seward Peninsula
south will begin as snow but briefly...then change to freezing
rain. Though amounts from Nome south should be in the advisory
range...the colder valleys of the northern Seward Peninsula and
lower koyuku/middle Yukon valleys could see amounts up to one
quarter inch so have issued ice storm warnings for these areas
tonight and into Thursday...as the associated warm front moves north to
Gambell to Saint Michaels at 3pm...then to Shishmaref to Kaltag
3am Thursday...and to Point Hope to near Tanana 3pm Thursday...the freezing
rain will turn to occasional light rain as temperatures rise into
the 30s. North of the Arctic Circle precipitation should be mostly snow
for this event with a chance of freezing rain.
Farther east the affect of the warm front in producing
precipitation may become limited due to the strong subsidence
under the upper ridge...though forecast models are indicating a
swath of what would be rain or freezing rain moving east...mainly
from Nenana and Fairbanks and Eagle northward. For now the
forecasts for the central and eastern interior are treating the
precipitation as chance or slight chance. But as successive model
runs come in this will have to be evaluated more carefully. The
prime period for the possible freezing rain event in the Fairbanks
will be Thursday night and Friday.
The North Slope...at least the western Brooks range and western
Arctic coast...is also a candidates for some light freezing rain
to fall ahead of the warm front...in particual Thursday night and
Friday...as the warm front moves to Wainwright to Bettles to near
Fairbanks at 3am Friday.
Coastal hazard potential days 3 and 4...none
Ice Storm Warning for akz210-akz216.
Freezing Rain Advisory for akz211-akz212-akz213-akz214-akz215.
Winter Weather Advisory for akz203-akz204.
Gale Warning for pkz210-pkz220.
Brisk Wind Advisory for pkz200-pkz215-pkz225-pkz230-pkz240-
Jl Dec 13