Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
312 PM EST Tue Feb 26 2019
Valid 12Z Sat Mar 02 2019 - 12Z Wed Mar 06 2019
...Summary...
A powerful storm track is expected to hold in place from off
eastern Asia northeastward into the Bering Sea over the next week.
A mean trough aloft will bring different systems entering the
Bering Sea and moving through the Aleutians toward western Alaska,
with eastward motions limited by an amplified mid-upper level mean
ridge built up through the Interior and North Slope.
...Guidance and Predictability Assessment...
A composite blend of reasonably well clustered guidance from the
latest GFS/ECMWF and GEFS/ECMWF ensemble means offers a good basis
for the forecast this weekend. These ensemble means mesh best with
the ECMWF Monday, but increasing model spread suggests transition
to the still compatable ensemble means days 7/8. This forecast
strategy was collaborated with local weather forecast offices and
maintains good continuity with yesterdays WPC forecast suite.
...Weather Highlights and Hazards...
A lead storm will lift through the Arctic Saturday and away from
the state as the next deep storm effects the Aleutians and western
Bering Sea this weekend. This storm lifts over the Bering and
gradually weakens through early next week, with lead effects
working into southwest Alaska/AKpen and western Alaska. Yet
another deep low in this series seems on track toward the
Aleutians day8.
Most of the state will remain mainly precipitation free under the
mean upper ridge with rain/snow confined to the Aleutians and
western Alaska. Temperatures will be mostly above average through
the medium range period, but variable through the interior. The
greatest temperature anomalies will likely occur across the North
Slope into northwestern Alaska where temperatures may be 35-45 deg
F above average. Temperatures over the Panhandle will be slightly
below average due to northeasterly/easterly flow out of Canada,
especially for the weekend and into next week as the upper high
slips northward and allows a cool push of air to leak
southwestward out of the Yukon.
Bullet points from the WPC Days 3-7 Hazards chart:
https://www.wpc.ncep.noaa.gov/threats/threats.php
High significant wave heights effecting coastal western Alaska,
Mar 1-Mar 2.
High winds across the Aleutians, Mar 2-Mar 4.
Schichtel
WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can be found at:
https://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml
https://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html