Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
627 PM EST Fri Feb 07 2020
Valid 12Z Tue Feb 11 2020 - 12Z Sat Feb 15 2020
...Guidance and Uncertainty Assessment...
The models offer less than stellar run to run continuity and
greater than normal forecast spread days 4-7. Accordingly and
after collaboration with the local WFO offices, the forecast
starting point for the WPC Alaskan product suite was a composite
blend of more reasonably compatable guidance from the 12 UTC
NAEFS/ECMWF ensemble means and the 19 UTC National Blend of
Models. Forecaster adjustments were applied to this smooth blend
to add increased detail consistent with individual weather feature
predictability and support. This especially included the deepening
of offshore lows.
...Weather Pattern and Hazards Highlights...
The mid-upper flow pattern next week is expected to feature a mean
trough/low through the Aleutians into the west-central Bering Sea
that pumps a mean downstream ridge up over the Alaskan Peniinsula
and Southwest Alaska. This pattern will favor development of a
series of potentially deep storms that may support a threat of
heavy precipitation/winds/seas across the Aleutians and
west-central Bering Sea early-mid next week with a later week
threat also working into the Alaskan Peninsula and Southwest
Alaska.
Lead surface high pressure/cold air settled over the Interior
moderates later next week as heights gradually rise to the lee of
the ridge with upper trough eastward ejection into Canada. Arctic
stream energies digging into the base of this trough may combine
with an uncertain influx of Gulf of Alaska trough energies to
meanwhile support a few lows that may present some heavier
precipitation threat to the Southeast Panhandle.
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:
- Heavy precipitation for parts of the Alaska Panhandle and
mainland Alaska, Mon Feb 10.
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