Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
433 PM EST Thu Nov 21 2019
Valid 12Z Mon Nov 25 2019 - 12Z Fri Nov 29 2019
A robust Bering Sea system will lift toward northwestern Alaska
Tue/Wed next week as the upper flow then trends toward
quasi-zonal. An uncertain evolution in the central North Pacific
has slowly come into better agreement, with a closed low south of
the Aleutians eventually lifting north-northeastward and
weakening.
12Z GFS/ECMWF offered reasonable clustering with the 12Z GEFS mean
and 00Z ECMWF ensemble mean so that a blended solution served as a
good starting point for the forecast through about next Thursday.
Question by then is how the central Pacific system ejects toward
the Gulf and how deep it may be. With a trend toward flatter flow
(though deepening troughing over the western CONUS), driven by a
shifting in the anomaly pattern upstream off Asia, a weaker
solution was favored. In the Bering, model consensus (except the
12Z Canadian) suggested a deeper system than depicted 24 hrs ago
but keeping the parent low over northeastern Russia. Cold front
will bring in a surge of southerly winds to the west coast of
Alaska as near-offshore ice is still forming. This area was
depicted on the WPC day 3-7 hazards chart again for the
wind/wave/precipitation threat.
Fracasso
Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
Hazards:
- Heavy precipitation across portions of western Alaska, Mon-Tue,
Nov 25-Nov 26.
- Heavy precipitation across portions of mainland Alaska, Wed, Nov
27.
- High winds across portions of western Alaska, Mon-Wed, Nov
25-Nov 27.
- High significant wave heights for coastal portions of western
Alaska, Mon-Tue, Nov 25-Nov 26.
WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can also 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