Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
240 PM EST Sat Nov 10 2018

Valid 12Z Wed Nov 14 2018 - 12Z Sun Nov 18 2018

Upper troughing is forecast to linger and be replaced over the
Gulf of Alaska next week into next weekend, reinforced by a couple
systems from the south and west. Upper ridging or a closed upper
high will meander over northeastern Russia, favoring weaker
disturbances to slide across the North Slope with little fanfare.
The models have mostly been aligned in the large scale but have
had trouble being consistent on individual systems. Of the
ensembles, the ECMWF ensemble mean has been more robust than the
GEFS mean and continued to favor its solution above all else
though even it has enough spread among its members to decrease its
gradient by next weekend. The 12Z GFS and 00Z ECMWF were close
enough to the ECMWF ens mean to use that blend (with some 06Z GEFS
mean) as a starting point. This kept good continuity from 24 hrs
ago with the lead system into the Gulf late Thu into Fri. Second
system through the Aleutians has been much less consistent in
track and timing, but should eventually find its way to the Gulf
given the tendency for the downstream ridge to bounce back. ECMWF
ensemble mean was stronger with said ridge and was the preference
over the GEFS mean, though for day 8 they were pretty close.


Fracasso



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