Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
440 PM EDT Mon Jul 29 2019
Valid 12Z Fri Aug 02 2019 - 12Z Tue Aug 06 2019
The flow pattern over Alaska during the medium range (late
Thursday into late next Monday) changes with time, as a trough
across Alaska gets replaced with an Omega Block extending across
much of the eastern Pacific downstream of a significant upper
trough across northeast Asia. The guidance showed good agreement
early on before discrepancies increased in and near the Bering Sea
with time. To account for this, the pressures, 500 hPa heights,
and winds started a blend of the 00z Canadian, 00z ECMWF, 06z GFS,
and 00z UKMET early before making the blend more evenly split with
the 00z NAEFS mean and 00z ECMWF ensemble mean by early next week,
with some tweaks made thereafter to better define features. The
remainder of the grids were evenly split between the ensemble
means (half of the blend) and the 06z-12z GFS, 00z Canadian, and
00z ECMWF guidance (composing the second half of the blend).
Eastern and southeastern Alaska are expected to be the sunnier
areas this period, with highs in the 60s near the coast and 70s
inland. To the west and north, cloudy skies should prevail as
disturbances ride around the eastern side of the northeast Asia
trough bring the promise of skirmishes of heavy rainfall (1-3"
with locally higher amounts) from the Aleutians into northwest
Alaska.
Roth
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
- High significant wave heights for portions of the Arctic Coast
of Alaska, Thu-Fri, Aug 1-Aug 2.
- High winds across portions of the Arctic Coast of Alaska, Fri,
Aug 2.
- High winds across portions of western Alaska, Sat, Aug 3.
- Heavy rain across portions of northwestern Alaska, Sat-Sun, Aug
3-Aug 4.
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