Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
541 PM EDT Sun Jun 19 2022
Valid 12Z Thu Jun 23 2022 - 12Z Mon Jun 27 2022
...Overview...
An increasingly ridgy pattern will be seen in and near southeast
AK from this weekend onward, with a couple deep layer cyclones
across the Bering Sea/Aleutians from late this week into early
next week. Temperatures overall will be above average.
...Guidance Evaluation/Predictability Assessment...
The guidance shows reasonable agreement early; a compromise of the
12z GFS, 12z Canadian, 12z UKMET, and 12z ECMWF resolves any small
issues. While the guidance shows some dispersion near the
Aleutians late in the period at 500 hPa and the surface, the GFS,
ECMWF, and Canadian show surprising agreement on the 5 day QPF
covering day 4-8/Thursday into next Sunday. There are some
differences upstream across and north of Siberia that impact
frontal progression towards northwest AK. To deal with the 500
hPa and surface pressure issues, used increasing amounts of the
00z ECMWF ensemble mean and 12z NAEFS mean with time, eventually
becoming half of the overall blend. The remainder of the grids
are based on a more even blend of deterministic and ensemble mean
guidance, the National Blend of Models.
...Weather and Hazard Highlights...
The Aleutians and western mainland Alaska should be the cloudiest
and rainiest, with 1-2" of rain and gale force winds (35-40 kts)
expected in the Aleutians Thursday into Friday, between an area of
low pressure to the west and a near-record strong high pressure
system for June near Cold Bay. After a shortwave aloft a cold
front pass by interior AK, leading to some temperature moderation
late this week, southeast AK will become under the aegis of
strengthening mid-level ridging and partly cloudy skies this
weekend into early next week -- the clearest region of AK between
Thursday and next Sunday. Temperatures will become hot for
interior southern and southeast AK from this weekend onward, with
highs in the 80s expected. Cooler conditions will be expected
right along the coast, the Aleutians, and Brooks Range, but even
there,=, it will be warm when compared to June standards.
Roth
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