355
FXAK02 KWNH 302206
PMDAK

Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
505 PM EST Thu Jan 30 2025

Valid 12Z Mon Feb 03 2025 - 12Z Fri Feb 07 2025

...Guidance Evaluation and Preferences...

A highly amplified and warming upper ridge will build and peak
over the Mainland into early next week. This will increasingly
tend to force weather focusing systems around the periphery.
Prefer a composite of reasonably clustered 12 UTC
GFS/ECMWF/Canadian guidance to provide maximum detail consistent
with above normal predictability for Monday and Tuesday. The 12
UTC models then seem to work too much lower predictability
shortwave energy/height falls into the blocking ridge at longer
time frames compared to multi-model ensemble means. Big ridges
tend to linger. Accordingly, switched to compatible
GEFS/ECMWF/Canadian ensemble means guidance and added WPC manual
adjustments to provide better system definition with rounding
systems and associated weather foci as consistent with individual
predictabilities. This acted to maintain best possible WPC product
continuity.

...Weather/Hazards Highlights...

A highly amplified pattern should be well in place into early next
week for Alaska and vicinity as highlighted by an anomalously
strong ridge built over the Mainland and a series of transient
systems rounding on the periphery. This should promote a period of
much warmer than average temperatures across much of the Mainland,
with the exception of cooled valleys of the Interior and across
the Southeast. Meanwhile, mean upper troughing will prevail well
into next week from the Aleutians up through the western to
central Bering Sea and into the Arctic Ocean around the top and to
some degree working into the Mainland upper ridge over time.
However, there remains quite a bit of uncertainty beyond early
next week on individual shortwaves/surface lows. Moist inflow east
of this trough will increase precipitation and enhanced wind
chances to monitor for more reliable guidance signals for periodic
possible impacts across the Aleutians, Alaska Peninsula, the
western Mainland and parts of the North Slope. The pattern looks
to turn gradually less amplified with breakdown of the upper ridge
into next week.

Above to well above average temperatures will shift from west to
east this weekend across the mainland beneath a strong upper level
ridge. The greatest anomalies will be on the North Slope and parts
of far western Alaska where daytime highs could be 30+ degrees
above normal Sunday-Tuesday. The exception to the warmth will be
across cooled valleys of the Interior with inversions and for
Southeast Alaska where the upper low lingering just south of the
Panhandle will keep temperatures below average into at least mid
next week.

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

$$