Scientific Forecaster Discussion
Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
244 am akst sun Mar 1 2015
An active and progressive large scale weather pattern is expected
to continue during the next week to 10 days.
a strong short wave trough now extending north-south along the
alcan border will move rapidly eastward into northwest Canada
today. A smooth high pressure ridge over Bristol Bay and the
northern Bering Sea will build through Sun night. The ridge axis
will extend from Dall Point to the eastern north Gulf Coast and
southeastward by 3 am Monday. By 3am Tuesday the ridge will extend from
the eastern Arctic coast to the southern Yukon territory. The
ridge will become flatter as it moves eastward into the Yukon and
northwest territories by 3 am Wednesday. Another short wave trough will
move eastward to the chukotsk peninsula and the northern Bering
Sea by 3 am Tuesday and then split. Most of the short wave energy will
move northeastward across the northwest Alaska Tuesday afternoon...then
proceed on into the Beaufort Sea Tuesday night. The southern piece of
the short wave will drift slowly eastward into the interior
through Tuesday night while gradually dampening out.
A third short wave will move eastward to the northern Bering Sea
by 3 am Thursday. A much stronger southwest flow is expected to set up
over the northern Bering Sea by late Thursday night...and spreading
eastward across the northern Alaska Mainland Friday into Friday night.
The next short wave...number 4 in the current series...is likely
to be a strong one...currently prognosticated to move to the northern
Bering Sea by late Friday night. Current GFS/European model (ecmwf) runs and the gefs
ensemble mean are in reasonably good agreement on this pattern in
the medium range period. The short wave will be accompanied by a
moderately strong surface system. Current models differ some on
the surface low position at 3 am Sat...gefs/ECMWF ensemble means
indicating the low center at 3 am Sat will be somewhere near St
Lawrence Island. This pattern has the potential to produce heavy
snow over the northern Bering Sea and the western Alaska coast Friday
into Friday evening...and over much of the Alaska interior later Friday
night into the weekend. Storm total snowfall amounts of 8 inches
or more at Fairbanks are uncommon...but are most often associated
with this type of synoptic scale pattern which can import
substantial moisture into the Alaska interior.
temperatures over the Arctic slope and interior have sharply fell
behind the passage of a strong cold front moving rapidly eastward.
The rapid pressure rises and sharp cold advection have already
occurred over the central and eastern interior...and winds will be
decreasing rapidly during the remaining overnight hours. Maximum
wind gusts of over 35 miles per hour have been reported by many sites in the
eastern interior. The strongest gusts reported include 50 miles per hour at
the Fairbanks Airport...49 miles per hour at Eagle Summit...and 47 miles per hour at a
Colorado-op site near the Goldstream Airport.
On the central Arctic coast...blizzard conditions are still in
progress...but winds will diminish during the remainder of the
overnight hours into sun. The DeadHorse Airport reported a maximum
gust of 61 miles per hour Sat evening.
Winds on the western Arctic coast will shift to easterly Sun
afternoon or evening...and over the remainder of the Arctic coast
and interior Arctic slope by late Sun night. Wind speeds are
expected to be 25 miles per hour or less.
The eastern Arctic coast experienced severe blizzard conditions
in the evening. Point Thompson reported wind gusts in excess of
70 miles per hour during the evening...with a maximum gust of 76 miles per hour.
Blizzard conditions are still occurring there but winds are
starting to diminish. No wind observations are available from
Barter Island...but is very likely that severe blizzard conditions
with wind gusts in excess of 75 miles per hour have been experienced there.
Winds on the eastern Arctic coast will gradually decrease during
the remaining overnight hours into sun.
The next surface system on deck is a 987 mb low near 56n/169e...
associated with the next incoming short wave trough aloft.
This low is expected to split into two centers by 3 PM this
afternoon...with the northern 1000 mb center being located west
of the Gulf of Anadyr and the parent 995 mb low being about 200
miles to the south southwest...near 59n/171e. By 9 am Sat...
the northern center will fill to 1004 mb near cape Schmidt on
the northeast Siberia coast...with the southern 1004 mb center
being over the outer Gulf of Anadyr. A broad low pressure
trough extending north-south will envelop the two low centers.
By 9 am Tuesday...the northern center will redeepen to a 1000 mb
low centered 100-200 miles northwest of Barrow...with the southern
1004 mb center moving to near Bethel.
The next round of snow will begin over St Lawrence Island and the
northern Bering Sea Monday afternoon as the two low centers and the
short wave trough aloft approach. Snow will spread across the
Chukchi Sea and the Alaska West Coast Monday night and move into the
central and western interior Tuesday...and into the eastern interior
Tuesday night and Wednesday. Snow amounts of 3 inches or more will be
likely over the northern Bering Sea and Chukchi Sea Monday
night...with lesser amounts possible over the outer areas of the
Alaska West Coast.
As indicated earlier in the discussion...there is potential for
heavy snow over the northern Bering Sea over much of northern
Alaska south of the Brooks range beginning Friday and continuing
into the weekend as a very favorable synoptic pattern develops.
The evolution of this pattern will need to be monitored daily.
Blizzard Warning for akz203-akz204-akz206.
Winter Weather Advisory for akz205.
Gale Warning for pkz215-pkz235.
Gale Warning for pkz240.
Storm Warning for pkz245.
Rf Feb 15