Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
751 PM EDT Wed Jun 01 2022
Valid 12Z Sun Jun 05 2022 - 12Z Thu Jun 09 2022
...Overview and Weather and Hazard Highlights..
A weak, mean ridge over portions of the Mainland will separate
Arctic upper troughs/lows to the north of Alaska that periodically
force several fronts through the North Slope and northern Interior
from several closed upper level/surface lows in the North Pacific.
In this flow, a lead/lingering closed low and effects will slowly
weaken well offshore over the southern/southeastern Gulf of Alaska
which will provide focus for some convection for the Interior.
Additionally, cooler temperatures will trend warmer with time.
Some periodic chance for light to locally moderate precipitation
over southern/southeast Alaska as a series of easterly waves ride
underneath the mean ridge. A closed upper trough/low with
main/triple point surface lows will slowly transition from just to
the south of the unsettled Aleutians to well offshore over the
western/southwestern Gulf of Alaska as a moderate maritime threat.
...Guidance/Predictability Assessment...
The models continue to have two troughs near the Arctic Ocean,
with one positioned to the northwest and one to the northeast of
the North Slope. The past several forecast cycles have shown these
two features fairly clustered for the first 1-2 days of the
extended forecast before the small-scale differences increase.
This remains true for this current run of the guidance.
Additionally, the trend of a mean trough over the Gulf of
Alaska/north Pacific Ocean will persist with multiples systems
passing through the region. Overall the predictability of the
large scale pattern and its evolution, particularly with the
ensemble means, is above average even with small scale
differences. The initial blend began with equal parts of the 12Z
CMC/GFS/UKMET/GFS for the first 1-1.5 days before transitioning to
100% GEFS/NAEFS/ECWMF ensemble means for the mid and latter
periods.
Campbell
Hazards:
No significant hazards are expected over Alaska during this
forecast period.
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