Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
538 PM EST Sat Feb 15 2020
Valid 12Z Wed Feb 19 2020 - 12Z Sun Feb 23 2020
Strong positive height anomalies south of Kamchatka in the
subtropical Pacific (~25N/140E) will favor troughing in the Bering
Sea and western Alaska late next week into next weekend. The 12Z
models were in good agreement to start as a lead system pushes
inland over eastern areas and the Panhandle on Wednesday and a
second system traverses the Aleutians. That second system should
straddle the islands but then move toward Kodiak and toward the
southern portion of the Kenai Peninsula by early Fri. The GFS
again was just to the NW of the other deterministic and ensemble
consensus, which has been fairly steady the past two days.
Preferred to stay with the larger consensus which was very close
to continuity. Parent low will likely linger in the Gulf through
at least Sat. By next weekend, another system will likely push
eastward along the Aleutians thought the deterministic models
diverge north-south. Ensemble consensus was in the middle, along
the island chain, and this track was maintained in the manual
progs.
Temperatures near to above average in eastern areas will trend
back toward below average as colder air is dragged down from the
north behind the lead and second system. The Panhandle should see
nearer to average temperatures with mainly westerly onshore flow,
but a nearly daily chance of precipitation. Highest rain/snow
totals are likely over the southeast side of the Kenai Peninsula
eastward across Prince William Sound to Yakutat and through the
Panhandle. To the north, lead front on Wednesday will bring
several inches of snow to western areas toward the Brooks Range
(Galena to Kotzebue to Bettles).
Fracasso
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