Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
201 PM EST Fri Feb 22 2019

Valid 12Z Tue Feb 26 2019 - 12Z Sat Mar 02 2019

Little change to the big picture as a strong upper high will
remain in place over interior Alaska next week with troughing in
the western and central Bering Sea. Systems will lift northward
across the Aleutians into northeastern Russia with any frontal
boundary weakening near the western coastline in the Bering. By
next weekend, ridge may start to be eroded on the NW side of
Alaska but for now favored the guidance than maintained higher
heights given the tendency to destroy ridging too quickly at
longer lead times.

Used a majority weight of the recent 12Z GFS with the 00Z ECMWF
and a minority weight of both of their ensemble means to iron out
some track differences early in the period in the western Bering
-- models have been inconsistent on speed but not track. Trended
toward mostly the 00Z ECMWF ensemble mean by the end of next week
as it maintained higher heights than the GEFS mean. Still included
some deterministic weighting to refine the Bering system
placement.

Most of the state will remain precipitation-free under the upper
high with rain/snow confined to the Aleutians and into western
Alaska. Temperatures will be mostly above average but likely quite
variable through the interior due to inversions in the thermal
profile with little mixing. The greatest temperature anomalies
will likely occur across the North Slope into northwestern Alaska
where temperatures may exceed 25-35 deg F above average.
Temperatures over the Panhandle may be slightly below average due
to northeasterly/easterly flow out of Canada.

Fracasso


WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can be found at:

http://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif
http://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml
http://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html