Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
548 PM EST Wed Jan 20 2021
Valid 12Z Sun Jan 24 2021 - 12Z Thu Jan 28 2021
...Overview and Guidance/Uncertainty Assessment...
Ample closed low/trough tracks into the Bering Sea and complex
downstream energy transfers into and undercutting periodic lead
upper ridging over the Interior and the Gulf of Alaska really have
the models scrambling to maintain deepened embedded system
continuity much beyond day 4 forecasts. A 12 UTC
GFS/ECMWF/UKMET/UKMET model composite seems reasonable Sunday, but
fast growing forecast spread and run to run variance makes it
difficult to favor any particular model onward and instead prefer
a more compatible blend of the 12 UTC GEFS/ECMWF ensemble means.
This maintains good WPC product continuity that still highlights
the most predictable low systems showing deeper development and
threat potential.
...Weather/Hazards Highlights...
There is a good guidance signal showing that a reasonably deep
Aleutian/Bering system Sun/Mon will bring breezy conditions/waves
and precipitation to the unsettled region. This should spread
along the western coast of Alaska as the front pivots and
redevelops to the southeast across the AKPen into Tue. Yet another
deepened system could spread additional rain/snow and a threat of
high winds/waves to the Aleutians by Tue-Wed. This system offers
less predictability along with details of potential subsequent
effects into western Alaska and back into a possibly stormy Gulf
of Alaska later next week.
The majority of the state will see above to much above normal
temperatures this weekend, with the most extreme anomalies likely
to be over northern and western areas. Temperatures should cool
back toward more typical late January values next week. The
Panhandle may see a larger area of below normal readings after a
modest lead weekend system departs and offshore flow increases
with frontal surge.
Schichtel
Hazards:
- High winds across portions of the Aleutians, Tue-Wed, Jan 26-Jan
27.
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