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Northern Alaska forecast discussion 
National Weather Service Fairbanks Alaska
1217 PM akst Friday Mar 6 2015

Discussion...

Upper air...
a moist southwesterly flow aloft will continue over northern Alaska
south of the Brooks range through Sat evening...then weaken Sat
night as a cold trough moves eastward across northern Alaska. A
short wave trough over the northwestern Bering Sea will move to
the Alaska West Coast by early Sat morning...then dampen out Sat
as it moves across the Alaska interior. A cold upper low near
65n/150e over inland Siberia will move to near Dall Point by Sun
morning...and to the eastern north Gulf Coast by early Monday
morning. The upper low and cold cold trough will bring a
significantly colder air mass to all of northern Alaska by
sun...with below normal temperatures likely continuing into
most of next week. Current operational model runs and their
ensemble means are in good agreement out through Wednesday. Forecasts
confidence decreases thereafter ... the GFS and its ensemble
mean rather bullish about setting up a warm return flow over the
eastern interior as the trough axis is pushed westward into the
western interior. European model (ecmwf) and its ensemble mean keep a persistent
broad trough over northern Alaska late in the medium range
period.

Surface... a 986 mb low centered about 300 miles west southwest
of St Lawrence Island will dissipate over Norton Sound Sat
morning. A 991 mb triple point low near St Lawrence Island will
weaken to a 995 mb center near Kotzebue by Sat morning...then
becoming an elongated 999 mb low over the Brooks range by Sat
afternoon. This elongated low will consolidate into a 997 mb
center about 100 miles east of inuvik by Sat evening then move
farther eastward later Sat night. The associated occluded front is
now moving onshore along the West Coast and will proceed across
northern Alaska this afternoon and tonight.

Significant snowfall is expected over most areas of northern
Alaska south of the Brooks range over the weekend. Given the fact
that warm advection across the interior is weak and with
relatively warm air at the surface...strong overrunning is not
expected and snowfall amounts are not expected to reach warning
level anywhere in the eastern interior. Heavier amounts are
expected over the West Coast and western interior...where winter
storm warnings for heavy snow are currently in effect. Winter
weather advisories continue in effect for most of the central and
eastern interior zones.

Substantially colder temperatures are expected over all of
northern Alaska by sun as the eastward moving cold trough aloft
brings a sharply colder airmass with it. This cold air mass will
likely hang in over northern Alaska for at least most of next
week.



&&

Afg watches/warnings/advisories...
Winter Storm Warning for akz208-akz209-akz210-akz211-akz212-
akz213-akz214-akz215-akz216-akz217.

Winter Weather Advisory for akz218-akz219-akz220-akz221-akz222-
akz223-akz224-akz225-akz226.

Brisk Wind Advisory for pkz200-pkz210-pkz215-pkz220-pkz225-
pkz230.
&&

$$

Rf Mar 15

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