Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
709 PM EDT Thu Jun 23 2022
Valid 12Z Mon Jun 27 2022 - 12Z Fri Jul 01 2022
...Pattern Overview and Weather and Hazard Highlights...
The strong upper ridge drifting over the mainland and northwestern
Canada should promote a broad area of above to much above normal
temperatures during the period, albeit with the center of an
eastern mainland/northwestern Canada upper ridge gradually
drifting more into Canada by the middle of next week. Expect the
most notable/impactful anomalies to be over the Interior and
Panhandle. The Panhandle may see the greatest departures from
normal and best potential for a few locations to challenge daily
records. Farther west, an upper trough with embedded low should
persist over the Bering Sea and Aleutians for most of the period.
A main but modest surface low is now expected to track into the
Aleutians/Bering Sea by early next week and spread lead/wrapping
moderate precipitation across the Aleutians and into the
AKpen/Kodiak Island/southern AK as well as up into
Southwest/Western Alaska with approach during the course of next
week. Upstream, another system emerging from the western Pacific
may start to influence the Aleutians after midweek. A deep upper
low initially north of Siberia is still likely to remain well
northwest/north of the mainland, but some differences persist for
how surrounding flow could influence the northern mainland. The
North Slope may see episodes of light precipitation if a front to
the north gets close enough to the region. Elsewhere, expect
precipitation to be lighter and more scattered over most areas
given the prevalence of upper ridging.
...Guidance Evaluation/Predictability Assessment...
Guidance now seem pretty well clustered through medium range time
scales, bolstering confidence in the larger scale pattern
evolution. However, the scale and complexity of flow embedded
systems still offer lingering uncertainties. The WPC Alaskan
medium range product suite was primarily derived from a composite
blend of the 12 UTC GFS/ECMWF/UKMET/Canadian for days 4-6
(Mon-Wed) and then added the GEFS/ECMWF ensemble means into the
composite in place of the UKMET for days 6/7 (next
Thursday/Friday). Product continuity is decently maintained and
individual system forecast differences seem well addressed with
this blending process, consistent with predictability.
Schichtel
Hazards:
- Much above normal temperatures across portions of the Alaska
Panhandle, Sun-Thu, Jun 26-Jun 30.
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