Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
404 PM EST Mon Jan 06 2020
Valid 12Z Fri Jan 10 2020 - 12Z Tue Jan 14 2020
...Weather/Hazards Highlights...
A building upper ridge over the North Slope and much of the
Interior will partially ease the current cold snap, with lingering
much below normal air held over the eastern Interior/Southeast
with post-frontal high pressure spread in from Canada.
Underneath, eastern Gulf of Alaska low development Friday has
trended deeper and more locally unsettled over the past few days
and that seems reasonable considering upper trough/low support in
amplified flow to the lee of the Interior upper ridge.
A main weather threat upstream will be from the Aleutians to the
Bering Sea as a major low with a substantial hazard of high
winds/waves and heavy precipitation tracks into the region
Friday-Sunday. Lead weather will also work with some vigor into
the western and southwestern mainland for the weekend. Flow
energies will also work downstream to an unsettled northern Gulf
of Alaska into next week, but offers more modest effects for
maritime interests and onshore to the southern Alaskan tier.
...Guidance/Predictability Assessment...
The 12 UTC GFS/ECMWF and GEFS/NAEFS/ECMWF ensembles remain better
clustered than normal through the weekend, bolstering forecast
confidence. Prefer a composite blend along with the 19 UTC
National Blend of Models to maintain good WPC continuity. Opted
for a blend of these still compatable ensemble means days 7/8 in a
period of quickly growing forecast spread. Manual adjustments were
applied to depict deeper Aleutian/Bering Sea low developments that
offer an increased maritime and coastal threat considering
favorable support aloft.
Schichtel
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 the Alaska
Panhandle and mainland Alaska, Thu-Mon, Jan 9-Jan 13.
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