Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
328 PM EST Tue Jan 08 2019

Valid 12Z Sat Jan 12 2019 - 12Z Wed Jan 16 2019

Model guidance still showing upper ridging building across Alaska,
forcing the mid-level low over the Arctic to retreat from northern
Alaska. This blocking will ensure an active, wet pattern over
southeastern Alaska through the medium range period. Models show a
parade of occluded systems moving across the Aleutians,
southeastern Alaska/Gulf of Alaska. In terms of model consensus,
the 12Z GFS lined up well with the 00Z ECMWF with the overall
pattern especially in Days 4 and 5 (Saturday and Sunday). However,
timing with occluded systems begin to diverge between the GFS and
ECMWF on Days 6-8. The 00Z ECMWF lined up well with the 00Z ECMWF
ensemble mean and the 06Z GEFS mean. The WPC blend was based on a
12Z GFS/00Z ECMWF blend for the first two periods, and increased
the ensemble means along with keeping the ECMWF for the rest of
the medium range period.

The northern and western portions of Alaska, especially in the
interior, will be well below average for this time of year. In
fact, some overnight lows will dip into the minus 40s in some of
the valleys. A gradual warm up will begin on Monday and continue
into midweek. The Aleutians, south-central and southeast Alaska
will experience precipitation for much of the medium range period.
Southwest Alaska can expect an increase in precipitation this
weekend--drying out by late Monday and into Tuesday. The rest of
Alaska will remain dry.

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