Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
321 PM EST Fri Mar 01 2019
Valid 12Z Tue Mar 05 2019 - 12Z Sat Mar 09 2019
A strong upper high in the short term will give way to ridging
over northeastern Alaska next week that will only slowly trend
weaken by the end of the period. This favors a continued stormy
pattern for the Bering Sea/Aleutians and western/southwestern
Alaska with only fringe affects farther east. The models/ensembles
were fairly well-clustered through the period and the 12Z
FV3-GFS/00Z ECMWF were near their means and each other for much of
the period. The notable exception was Tue/Wed as the ECMWF was
slower than the rest of the guidance but not unreasonable given
the ensemble lows spread and low predictability of these sfc
waves. Median positioning sufficed.
For next Wed-Sat, a lead deep system and trailing perhaps deeper
system will traverse the Bering just north of the Aleutians and
slide eastward. This will bring strong winds and high waves to the
region over more open water than what is typical for this time of
year. Precipitation will focus along/ahead of the front into
Southcentral with southerly flow Thu/Fri. Incorporated more
ensemble weighting (especially ECMWF ensembles) to form a
consensus position/track in the Bering with another deep system
next Fri/Sat.
Fracasso
Bullet points from the WPC Days 3-7 Hazards chart:
https://www.wpc.ncep.noaa.gov/threats/threats.php
- High winds across portions of western Alaska and the Alaskan
Peninsula, Mon-Wed, Mar 4-Mar 6.
- High winds across portions of the Aleutians, Wed-Fri, Mar 6-Mar
8.
- High significant wave heights for coastal portions of mainland
Alaska, Mon-Tue, Mar 4-Mar 5.
- High significant wave heights for coastal portions of the
Aleutians, Wed-Fri, Mar 6-Mar 8.
WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can 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