Scientific Forecaster Discussion
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
209 PM akst sun Feb 1 2015
the long wave pattern consisting of Rex block with a blocking high
over interior Alaska and low over the NE Pacific will morph into
an Omega block with the ridge centered over the Bering Sea by Monday
and persisting through the end of the week as several strong short
wave make their way over the top of the ridge. By next weekend a
strong short wave will make its way south over interior Alaska.
This means the warm air aloft now over northern Alaska will cool
through the end of the week. Generally dry conditions will
persist over the interior through the week while the Arctic coasts
sees periods of light snow through the week with each short wave.
The first short wave trough in the northern Bering Sea will move
to the the Bering Strait north by 3am Monday...to McGrath to
deadhorse north by 3pm Monday and to Denali to Old Crow by 3am Tuesday.
There will be a surface cold front associated with this trough and
will address weather below with the surface front.
A second short wave trough now over eastern Russia will move to
the Chukchi Sea by 3an Tuesday and to Anaktuvuk Pass to Barter Island
and north by 3am Tuesday...then continuing southeast and weakening. Will see
another surface cold front associated with this feature.
850 mb temperatures range from 0c in SW Alaska and West Coast to
-14c in NE Alaska. Temperatures on Monday will remain the same in
the eastern interior and eastern North Slope but drop 4-8c along
the West Coast. On Tuesday will see temperatures drop significantly
over the North Slope with less change S of the Brooks range.
a 1040 mb high along the alcan border with a ridge over the
northern interior and Beaufort Sea will weaken through Monday night.
A 1012 mb low 300 nm northwest of Barrow will move to 150 nm north
of Barrow by 3am Monday...to 250 nm north of Barter Island by 3pm
Monday...to 300 nm north of Demarcation Point by 3am Tuesday and to 400
nm northeast of Demarcation Point by 3pm Tuesday as a 1006 mb low.
A cold front stretching south from the low will move to Barrow to
Nome by 3am Monday...to Barter Island to McGrath by 3pm Monday...to
Eagle to Denali by 3am Tuesday and south of the Alaska Range Tuesday.
Expect 1-2 inches of snow with the front. Expect flurries with the
front along the West Coast. Expect no precipitation inland south
of the Brooks range. Will see southeast winds 15-20 knots just ahead of the
front along the coasts...and easterly drainage winds 15g25kt
interior areas that normally get east winds. Expect west winds
15-25 knots with front along coast along with blowing snow...and
just light west winds inland.
Second cold front will move east over the Chukchi Sea Monday night
and to Barter Island to Cape Lisburne by 3pm Tuesday. Expect another
1-2 inches of snow with this. Expect west winds 20-30 knots with this
front along Arctic coast Tuesday. This could cause blizzard conditions
Tuesday east of deadhorse but still much uncertainty on this.
models all initialize too weak by about 20m on the h500 mb high
centered over interior Alaska. For this reason expect that the
first short wave trough moving east across Alaska tonight and Monday
will be weaker and further north than what is shown by models. This
means that expect clouds and snow to be further north than shown
This also means that the second trailing short wave trough that
moves east across northern Alaska Tuesday will be weaker as well and
favor the GFS solution on that which is a bit weaker than the
At the surface pressure are 1-4 mb higher than shown by models at
18z along the alcan border. Expect high in the Yukon to remain a
few mb stronger than models show through Monday with east winds several
brisk Wind Advisory for pkz210-pkz225.
Jb Feb 15