Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
500 PM EST Sat Nov 07 2020
Valid 12Z Wed Nov 11 2020 - 12Z Sun Nov 15 2020
...Guidance/Predictability Assessment...
Model run to run continuity is less than stellar through medium
range time scales in an active pattern with above normal forecast
spread associated with a series of dynamic embedded features.
Accordingly, and in collaboration with local forecast offices, the
WPC Alaskan medium range product suite was primarily derived from
a composite blend of the 12 UTC ECMWF ensemble mean, the 12 UTC
GEFS/ECMWF ensemble means and the 19 UTC National Blend of Models.
Despite it's own run to run variance, the 12 UTC ECMWF model was
included in this blend to provide better offshore low system
detail/strength as consistent with favorable upper support
potential since this model seemed most in line with ensemble
means. WPC continuity was average to marginal.
...Weather/Threats Highlights...
Deep Bering Sea low pressure next midweek will bring bouts of
strong winds/waves and enhanced precipitation from the
Aleutians/Bering Sea into parts of the western/southern mainland.
Heavy precipitation emphasis will increasingly transition to the
southern coast/Panhandle later next week and weekend, as low
pressure becomes established over the quite unsettled Gulf of
Alaska and as northern Bering low pressure slowly weakens. In this
pattern, above to well above normal temperatures next week for
much of the state will significantly cool, especially maximum
values, late next week into next weekend as an upper trough/low
moves overhead.
Schichtel
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
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