Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
101 PM EDT Tue Jul 17 2018

Valid 12Z Sat Jul 21 2018 - 12Z Wed Jul 25 2018

...Guidance and Predictability Assessment...

The current run of deterministic and ensemble means are fairly
clustered with the trough/ridge/trough pattern through the
extended periods, with some lingering timing and amplitude
differences with embedded systems. A blend of the 00 UTC
ECMWF/ensemble mean, 12 UTC GFS and 06 UTC GEFS/NAEFS ensemble
means were the preferred choice and were used as the starting
point for the WPC medium range product suite. 

...Weather Highlights and Hazards...

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. This will likely support the slow movement of the
front which will act as a focus for scattered precipitation across
northern sections of the state.

Initially precipitation will linger as a slow moving system passes
through the Southeast panhandle. Another low pressure system will
be advancing through from the Bering Sea over the Aleutians into
the Gulf of Alaska, ushering in widespread precipitation to the
Southwest and southern tier of the state through the weekend.
Additional deepened shortwave energy slated to dig behind this
feature may renew weekend focus down over the Aleutians then
southwest Alaska.

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