Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
418 PM EST Sat Feb 20 2021
Valid 12Z Wed Feb 24 2021 - 12Z Sun Feb 28 2021
...Overview and Guidance/Uncertainty Assessment...
The 12 UTC GFS/GEFS mean and 00 UTC ECMWF/ECMWF ensemble mean seem
best clustered at medium range time scales. A composite solution
is preferred to highlight the most predictable weather features.
Leaned blend emphasis in favor of the ensemble means by days 7/8
consistent with growing model forecast spread. The WPC medium
range product suite was primarily derived from these WPC blends
along with the National Blend of Models in a pattern with near
average forecast predictability/uncertainty. This solution
maintains good WPC product continuity.
...Weather/Hazards Highlights...
A series of deepening lows in an energetic Pacific stream will
work across the Bering Sea/Aleutians all next week in an active
pattern. This may favor a downstream warming trend across
southwest Alaska and much of the Interior midweek into next
weekend, but lingering upper troughing and flow underneath may
inhibit warming over an unsettled North Slope and possibly the
eastern Interior. A main storm track will focus precipitation and
wind/waves to the Aleutians, the AKpen and southwest/western
Alaska as they progress eastward, with energies to track into an
unsettled Gulf of Alaska to support periodic heavier precipitation
into southern and southeast Alaska.
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