Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
600 PM EST Mon Feb 15 2021
Valid 12Z Fri Feb 19 2021 - 12Z Tue Feb 23 2021
...Overview and Guidance/Uncertainty Assessment...
Latest model and ensemble guidance shows an area of upper level
troughing with potential for multiple embedded closed lows within
an area extending from northern Alaska to the northern half of
Alaska. Relatively progressive flow should prevail across the
North Pacific, and this flow will likely carry multiple waves of
low pressure along the Aleutians and into the Gulf of Alaska. The
pattern aloft over the mainland will favor the persistence of
generally lower pressures over the Gulf of Alaska, with
corresponding precipitation focusing along the southeastern coast
and Panhandle region.
For most forecast specifics, guidance has been sufficiently
diverse and variable to recommend a 12Z operational model blend
for about the first half of the period, and then roughly 2/3rds of
the EC/NAEFS means as individual solutions increasingly diverge.
...Weather/Hazards Highlights...
The overall pattern will favor precipitation over the southeastern
coast and Panhandle during much of the forecast period, with the
best potential for the heaviest precipitation late Friday through
Saturday night. Multiple rounds of showers and gusty winds are
likely for the Aleutians as multiple waves of low pressure pass
through this region.
Most of the Panhandle should see below normal temperatures during
most of the forecast period. Across the mainland, expect the
start of the period to feature below normal readings over the
North Slope and far west, while remaining areas will likely be
near to slightly above normal. With time expect a colder trend
that will steadily expand the coverage of below normal anomalies,
reaching nearly the entire state by the beginning of next week.
Hamrick
Hazards:
- Heavy precipitation across portions of southern Alaska, Thu, Feb
18.
- Much below normal temperatures across portions of mainland
Alaska, Sun-Mon, Feb 21-Feb 22.
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