Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
521 PM EST Sat Feb 13 2021
Valid 12Z Wed Feb 17 2021 - 12Z Sun Feb 21 2021
...Weather/Hazards Highlights and Guidance/Uncertainty
Assessment...
Midweek upper troughing over the North Slope is expected to dig
increasingly down into western Alaska later next week/weekend.
This will support frontal cooling and unsettled conditions through
this period to include some daily enhanced snow threats. This
pattern offers average to above average predictability.
To the south, there is also a good guidance signal that an
amplified upper trough and deepened surface systems will work
across the Gulf of Alaska Wed-Fri and act to weaken lead upper
ridging. Expect flow will focus moderate to heavy precipitation
mainly into southern and southeastern Alaska, especially over
favored terrain.
Upstream, increasingly progressive flow will subsequently feed
across the Aleutians and Pacific to the Gulf by next weekend in a
transitional pattern with gradually decreasing predictability for
a series of systems with modest local focus.
The WPC Alaskan medium range product suite was primarily derived
from a composite blend of reasonably well clustered mid-larger
scale guidance the 12 UTC GFS/ECMWF, GEFS/ECENS means and the 19
UTC National Blend of Models.
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