Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
228 PM EDT Sat Oct 05 2019
Valid 12Z Wed Oct 09 2019 - 12Z Sun Oct 13 2019
Models and ensembles show an amplified but progressive pattern in
place across Alaska and vicinity for the extended period. Guidance
consensus was good into day 4/Wed and the larger scale flow
evolution even seems fairly well depicted by most guidance through
day 8. Small-mid scale weather focusing systems embedded within
the overall flow do offer increasing timing variance days 5-8, but
the 00 UTC ECMWF/ECMWF ensembles and 12 UTC GEFS solutions seem
fairly well clustered. Accordingly, the WPC Alaskan medium range
product suite was primarily derived from that favored composite
blend.
Models show a relatively deep low pressure system moving east
across the Bering Sea to the west coast of mainland Alaska into
midweek, with energies tranferring inland and with ernest into the
northern Gulf of Alaska and southern/Southeast Alaska Thu/Fri
before exiting into Canada. This system includes some remnant
tropical moisture from what was Typhoon Mitag, so expect some
enhanced precipitation potential and a continued maritime risk.
There also remains a decent guidance signal supporting development
of another well organized weather focusing low pressure system
across the Bering Sea/Aleutians/Southwest Alaska Thu/Fri. This
system is also expected to emerge over the northern Gulf of Alaska
to feed an additional chance for heavier precipitation into
southern then southeastern Alaska next weekend along with an
associated maritime threat.
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
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