Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
623 PM EST Mon Dec 09 2019
Valid 12Z Fri Dec 13 2019 - 12Z Tue Dec 17 2019
Upper ridging will meander over the Arctic Ocean which will favor
successive troughing out of the Bering Sea and into the Gulf. The
storm track will be fairly progressive with rather well-defined
surface systems. After an old parent low dissipates near Kodiak
Fri, focus will turn to a system pushing through the southern
Bering Sea near the Aleutians. Deterministic models have shifted
northward to join the ensemble means from 24 hrs ago with such a
track. The latest 12Z GFS/ECMWF/UKMET formed a good starting
consensus position as the system (and its likely multiple lows
along the occlusion) develops its triple point near Kodiak by Sun.
By then, models diverge around the ensemble means but a split
among the GFS/GEFS and ECMWF/ECMWF ensemble mean sufficed to
start. Trend thereafter was for a bit slower progression through
the Gulf as the upper pattern may stay wavy and not become zonal.
This is likely due to the next system into the western Bering that
has trended stronger. It too may take a track along the Aleutians
and a blended solution remained through next Tue.
Temperatures will slowly trend from near/above average back toward
more typical December values by next week over at least the
interior. Precipitation will progress with each system from the
Aleutians to Southcentral to the Panhandle through the period.
Some enhanced rainfall/snowfall is possible along the coast and in
favored mountainous areas of the Kenai peninsula
(southeastward-facing) and perhaps Kodiak given the nearby surface
low tracks, but did not justify a heavy precipitation threat on
the Hazards chart.
Fracasso
Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards
https://www.wpc.ncep.noaa.gov/threats/threats.php
Hazards:
No significant hazards are expected over Alaska during this
forecast period.
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