Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
223 PM EDT Sun Jul 01 2018

Valid 12Z Thu Jul 05 2018 - 12Z Mon Jul 09 2018

...Guidance/Uncertainty Assessment and Weather
Highlights/Threats...

Guidance identifies three main medium range weather systems to
effect Alaska and adjoining waters. This includes a closed
trough/low over the western Bering Sea into late week as mainly a
maritime interest, a southern arctic trough/low to dig over the
eastern interior then Gulf of AK mid-late week/next weekend, and a
next weekend Aleutians and southern Bering Sea track of an
extratropical low associated with current West-Pacific Tropical
Storm Prapiroon. WPC progs show a threat of a decently deep low
there given tropical history.

Overall, the WPC product suite was mainly derived from a blend of
the GEFS/NAEFS/ECMWF ensemble means days 4-8 amid growing forecast
spread as mainly associated with the evolution of arctic troughing
into the interior and Gulf of AK. This uncertain system and stream
interaction scenario does offer potential to spread precipitation
over the eastern interior Thu/Fri and with energy transfer/phasing
to the eastern Gulf of AK and southern/southeast AK through next
weekend.

Schichtel

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