Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
659 PM EST Sat Mar 13 2021
Valid 12Z Wed Mar 17 2021 - 12Z Sun Mar 21 2021
...Overview and Guidance/Uncertainty Assessment...
The latest guidance continues to suggest a blocky pattern early in
the period with an upper low over the Gulf, ridge over the Bering
Sea, and a trough over eastern Siberia. The deterministic models
are in decent synoptic scale agreement through about Thursday. By
the second half of the forecast period, there is increasing model
spread with respect to the evolution of shortwave energy around
160W and its phasing with northern stream energy. At the surface,
a couple waves of low pressure will likely lift toward the
southeast coast and southern mainland early in the period, then
with some ridging expected to develop aloft for day 6-8 over
western mainland Alaska. The WPC blend consisted of the 12Z
ECMWF/GFS/UKMET through Thursday, followed by mostly a
ECENS/GEFS/ECMWF/GFS blend for days 6 through 8.
...Weather/Hazards Highlights...
Aside from possible waves of low pressure brushing or affecting
the southeastern coast and Panhandle early on, the rest of the
period should be relatively quiet from a sensible weather
perspective, especially for most of the mainland. The
southeastern Panhandle region has the best potential for organized
precipitation for the middle of the week, and the Aleutians will
likely have several rounds of rainfall passing through the region.
Aside from the North Slope where temperatures are forecast to be
slightly above normal, the rest of the region is expected to see
near to slightly below normal temperatures during this forecast
period.
Taylor/Hamrick
No significant hazards are expected over Alaska during this
forecast period.
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