Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
423 PM EDT Wed Jul 18 2018

Valid 12Z Sun Jul 22 2018 - 12Z Thu Jul 26 2018

...Guidance and Predictability Assessment...

Deterministic and ensemble means continue to be fairly clustered
and in agreement with the overall trough/ridge/trough/ridge
pattern that is forecast from the Bering Sea to Southeast
Alaska/western Canada. The Canadian model and its ensemble mean is
a few mb less amplified than the rest of the guidance, although
not necessarily unrealistic. Some lingering timing and amplitude
differences with embedded systems. Preferred a compromise of the
00 UTC ECMWF/ensemble mean, 12 UTC GFS and 06 UTC GEFS/NAEFS for
the WPC medium range product suite. 

...Weather Highlights and Hazards...

A series of low pressure systems will track from the Bering Sea to
the Gulf of Alaska spreading scattered to widespread precipitation
to the Aleutian Chain and portions of western and southern Alaska.
Additionally, a closed low spinning over the Arctic well north of
the state is now expected to only force modest height falls and
wavy surface front southeastward from the Chukchi Sea and Bering
Strait to the North Slope. A slow moving, or stalled, front which
will act as a focus for scattered precipitation across northern
sections of the state.


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