Alaska Extended Forecast Discussion
National Weather Service College Park MD
737 PM EDT Wed Jul 23 2025
Valid 12Z Sun 27 Jul 2025 - 12Z Thu 31 Jul 2025
...Overview...
An elongated upper trough with a closed low will extend from the
mainland into the Gulf while upper ridging will be over the
Aleutians. Temperatures will warm from west to east. An
associated surface frontal system will usher in a few rounds of
precipitation for the Alaska Range southward along the southern
coast to Southeast. Showers will also spread across portions of
the Interior by mid week. The lows will be slow to move in the
blocky pattern with an upper high north of the state, lasting into
early next week while gradually weakening.
...Guidance Evaluation/Preferences...
The models and ensemble means continue to have a good handle on
the evolution of the large scale pattern through the extended
period. The continues to be some increase in spread in regards to
low placement and location of QPF for by next week. However, the
guidance remains within the cluster for this blocky pattern with
an upper high over the northeast Pacific and another in the Arctic
Ocean, with Alaska's upper trough/low in between.
In previous runs, the GFS was noted to be on the north/east side
of the cluster which would suggest higher QPF to the Panhandle
and parts of the southern Coast for later in the period. Today the
GFS and CMC have trended toward each other while the EC is
suggesting a minor retrograde of the low position by favoring the
north/northwest side of the cluster.
The WPC forecast used a multi-model blend with heavier weighting
toward the ECMWF and GFS initially and included the GEFS mean and
EC mean by the start of the week and increased weighting to 45
percent by Thursday. This approach helped maintain continuity from
the previous forecast.
...Weather/Hazards Highlights...
Over the weekend precipitation is expected to focus in the Alaska
Range and Southcentral into Southeast Alaska over the weekend and
early next week with the upper and surface lows nearby.
Appreciable rainfall totals over the course of multiple days
however, Wet snow is possible in higher elevations of the Alaska
Range. A front approaching, along with potential upper troughing
coming into the Bering Sea and vicinity, could lead to rain
chances across the Alaska Peninsula and western Mainland into next
week, possibly spreading east across the Mainland.
Temperatures will be on the rebound back towards normal over the
weekend for much of the Mainland as upper ridging builds. Daily
maximums will generally be in the 70s in most Interior areas.
Temperatures may cool back down in the western Mainland early next
week depending on the evolution of the upper trough. Southeast
Alaska can expect temperatures to remain near to below average
with the low in the vicinity and increased cloud cover.
Campbell
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