Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
429 PM EDT Tue Jul 24 2018

Valid 12Z Sat Jul 28 2018 - 12Z Wed Aug 01 2018

The latest suite of deterministic and ensemble means continue to
be in decent agreement on the synoptic pattern, with a ridge over
the North Pacific and troughs moving over the Beaufort Sea,
Aleutians/western Gulf of Alaska and filling in across the Bering
Sea. The ridge is expected to remain anchored in place over the
Pacific Northwest Coast and eastern Gulf of Alaska; however the
southern parts retrogrades into the northeastern Pacific. Decent
clustering and slow progression with the feature in the Bering
Sea/Aleutians should support a surface front that lifts
north/northeast. This will keep increased cloud cover and
precipitation to portions of western Alaska. The preferred model
selection for this cycle was a combination of the 00Z
ECWMF/ensemble mean and the 06Z GEFS/NAEFS.

The precipitation coverage and quantity in association with
frontal system mentioned above may be affected by the evolution
Tropical Storm 14W (Wukong). As of now, the system is progged to
diminish prior to the extended forecast; however tropical moisture
may interact with the northern stream energy if if tracks faster
enough. Confidence is fair/below average at this time.

Campbell


WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can be found at:

http://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif
http://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml
http://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html