Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
505 PM EST Sun Nov 08 2020
Valid 12Z Thu Nov 12 2020 - 12Z Mon Nov 16 2020
...Guidance/Predictability Assessment...
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 day 4-6 Thursday-Saturday in a pattern with near average
predictability. 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. Prefer to quickly
transition to just the ensemble means day 7/8 amid growing
uncertainty and run to run variance in order to maintain max WPC
continuity.
...Weather/Threats Highlights...
Eastern Bering Sea low pressure later this week will bring bouts
of enhanced winds/waves and precipitation to the Aleutians/Bering
Sea and into western Alaska, potentially reinvigorated by
additional system development by early next week. Heavy
precipitation emphasis will increasingly transition to the
southern coast/Panhandle later week and the weekend as low
pressure becomes established over the quite unsettled Gulf of
Alaska. In this pattern, above to well above normal temperatures
in the short term will significantly cool, especially maximum
values, late week through 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