Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
633 PM EDT Sat Oct 09 2021
Valid 12Z Wed Oct 13 2021 - 12Z Sun Oct 17 2021
...Stormy Pattern Continues from the Aleutians through Southern
and Southeast Alaska...
... Guidance and Predictability Assessment...
The WPC Alaskan medium range product suite was primarily derived
from a composite of very well clustered guidance from the 12 UTC
GFS/ECMWF/UKMET and GEFS/ECMWF ensemble means along with the 19
UTC National Blend of Models. WPC product continuity is well
maintained in a stormy pattern with above normal predictability.
...Pattern Overview and Weather/Hazard Highlights...
Highly energetic and progressive flow aloft will support multiple
surface low pressure systems affecting portions of Alaska through
the period. A strong low pressure system will exit the eastern
Gulf of Alaska by midweek. Additional energies working from an
unsettled Bering Sea and Southwest Alaska/AKPen will then act to
reinforce a mean low position over the northern Gulf of Alaska
that is likely to linger/reform through the weekend and preserve a
favorable moisture and enhanced precipitation pattern for
south/southeast Alaska.
Upstream dynamic stream flow is expected to then drive a deep
storm into the Bering Sea by next weekend and downstream energy
transfer/triple point low developments should work across the
Aleutians/Southwest AK and the AKPen and into an again turbulent
Gulf of Alaska to also threaten maritime and southern Alaska by
later weekend.
Schichtel
Additional 3-7 Day Hazard Information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
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