Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
408 PM EDT Wed Oct 31 2018

Valid 12Z Sun Nov 04 2018 - 12Z Thu Nov 08 2018

...Guidance and Predictability Assessment...

The second half of the weekend starts out fairly quiet, with a
system in the Gulf of Alaska weakening while approaching the
Alaska Panhandle.  This will bring higher chances of precipitation
to that region--meanwhile the rest of the state remains dry. By
the start of the workweek, upper level trough and associated
occluded front enters the Bering Sea.  Chances of precipitation
will increase for the northern portions of Southwest Alaska and
western portions of the Far North. Meanwhile, height rises in the
eastern half of the state keeps conditions dry. The trough will
remain in place through midweek, bringing multiple frontal systems
into the Bering Sea from Tuesday through Thursday. Meanwhile, an
upper level low will approach the Gulf of Alaska by Tuesday and
nearing the coast of the Alaska Panhandle by Thursday.  Overall,
the 00Z ECMWF and 12Z GFS were in agreement with the broader
scale, but differed in details.  Because of inconsistencies with
both models run to run, decided to split the difference and used
the 00Z ECMWF ensemble mean and 06Z GEFS mean through the forecast
period.

...Weather/Hazards Highlights...

As the dying occluded system approaches the Alaska Panhandle on
Sunday, precipitation chances will increase and linger through
Tuesday. A brief period of lower rainfall chances is expected
before the upper low in the Gulf of Alaska moves closer to the
Alaska Panhandle, which will bring higher precipitation chances
back into the forecast by Wednesday and into Thursday. Rain and
snowfall chances are expected for Southwest Alaska and portions of
the Far North as systems approach the western parts of these
regions throughout the week. Precipitation chances also increase
for the Aleutians by Wednesday and Thursday.  In terms of
temperatures, Southwest Alaska and the Juneau region will have
high temperatures remaining above freezing--with temperatures
ranging from mid 30s to low 40s. The Far North will have highs in
the teens to single digits.



Reinhart



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