Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
555 PM EDT Sat Apr 23 2022
Valid 12Z Wed Apr 27 2022 - 12Z Sun May 01 2022
...Guidance/Predictability Assessment...
The WPC Alaskan medium range product suite was mainly derived from
a blend of the 12 UTC GEFS/NAEFS/ECMWF ensemble means for days 4-8
in a pattern with average to lower predictability aloft and with
associated surface systems despite overall reasonably similar
larger scale pattern evolutions. System variances remain less than
stellar even early into the medium range time scales. This plan
maintains good WPC product continuity. Coordination was limited as
NWSchat is down and lingering AWIPS issues seem to have been
enough overcome today to allow sensible weather grids production
and transmission from WPC. However, the 19 UTC NBM was not yet
available for this forecast package in GFE.
...Overview Weather/Hazard Highlights...
Lead lingering low pressure systems over the northern and eastern
Gulf of Alaska next week will continue some light to locally
terrain enhanced moderate precipitation from the southern Coast to
the Southeast Panhandle. Activity should wane with time as the
lows weaken and lose influence. Moderate precipitation will also
progress across the Aleutians and the Alaskan Peninsula/Kodiak
Island with a couple of frontal systems/main lows through the
period and as amplified upper low/troughing focus gradually
transitions outward from the southern Bering Sea to the Gulf of
Alaska later next week/weekend. Triple point low development may
redevelop next weekend low focus over the Gulf and potentially
enhance maritime affect and precipitation some by then to the
southern Alaskan coast. Much of the Mainland inland should remain
dry next week. However, uncertain but potentially amplified upper
impulse/trough developments and terrain may favor some very
localized enhanced snows for northern Alaska/the Interior. WPC
shows a mean upper trough aloft over the region whose development
seems reasonable considering expected upper ridge building earlier
into this forecast period into western Alaska. The ECMWF ensemble
mean seemed to show this best.
Schichtel
Additional 3-7 Day Hazard Information can be found on the WPC
medium range hazards outlook 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