Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
600 PM EST Tue Dec 31 2019
Valid 12Z Sat Jan 04 2020 - 12Z Wed Jan 08 2020
Active weather across the Alaska Panhandle should gradually
subside during the weekend as a surface cyclone over the Gulf of
Alaska weakens while the main jet stream pushes farther inland
across British Columbia. Models are in very good agreement on
this scenario. Thereafter, models have been indicating the
possibility of the next cyclone moving into the Gulf of Alaska
early next week but with a fair amount of spread. In particular,
the GFS has been advertising a weaker and slower system than what
the ECMWF shows. The 06Z GEFS did not offer a better agreement
with the EC solution either. However, the 12Z GEFS switched to a
faster and a more developed solution that agreed quite well with
the 00Z EC mean. Based on these considerations, the WPC grids for
Alaska were based on 65% to 70% blend of the 12Z ECMWF and the 00Z
EC mean with 30% to 35% of the 12Z GEFS. This blend yields a
cyclone that is stronger and more progressive than the consensus,
which agrees fairly well with WPC continuity.
Toward the middle of next week, a majority of the 00Z EC mean was
used. This yields a larger scale occluded cyclone skirting along
the Aleutians as the previous cyclone gradually weakens over the
Gulf of Alaska.
In terms of sensible weather, stormy conditions across the Alaska
Panhandle should gradually subside during the weekend. As the
next cyclone forecast to move into the Gulf of Alaska, winds and
waves along with snow should be on the increase once again from
coastal southern Alaska to the Panhandle by Monday, lasting into
Tuesday. Increasing storminess should also be spreading from west
to east across the Aleutians Tuesday and Wednesday. Meanwhile,
clear skies and radiational cooling are expected to bring frigid
conditions into southwestern Alaska where actual temperatures are
forecast to dip below -30 degrees for the interior sections.
Kong
Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
Hazards:
- Much below normal temperatures across portions of mainland
Alaska, Fri-Tue
WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can also be
found at:
https://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml
https://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html