Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
600 PM EDT Thu Apr 10 2025
Valid 12Z Mon 14 Apr 2025 - 12Z Fri 18 Apr 2025
...Gulf low pressure could lead to heavy precipitation and gusty
winds for southern portions of Alaska this weekend...
...Overview...
Guidance remains pretty consistent in showing a mean upper low
moving into the Gulf this weekend. This supports surface low
pressure in the Gulf region Sunday-Monday, eventually weakening as
it lifts northward into the southern Mainland. Mean moist
southerly flow near and east of the low will continue to bring
locally heavy precipitation to southern portions of the state into
Monday. Northerly to northwesterly winds and gap winds on the
backside of the low may be brisk behind this low over the weekend.
A second shortwave will shift through the Aleutians early next
week, with a decently strong surface low lifting northward into
the central Gulf by mid next week increasing precipitation chances
across the Southeast.
...Guidance/Predictability Assessment...
Model guidance is in fairly good agreement on the overall upper
pattern, but with plenty of uncertainty in the timing of systems
and details. The agreement concerning the upper low/surface low
weakening in the Gulf early period was good enough to warrant a
deterministic model blend for the first couple of days of the
period. After that, there continues to be some timing and
placement of the next deeper surface low lifting into the Gulf,
driven by smaller scale details in energy around the mean upper
shortwave/low. The CMC was on the slightly faster side of the
guidance, while the UKMET (through day 6) was displaced more
westward. Confidence in its exact track is low at this point, but
the deterministic GFS and ECMWF were closest to the ensemble means
and was the preferred solution (blended with the ensemble means)
for the later period forecast. Placement, timing, and track of
this low will have implications for precipitation amounts into
parts of the Southeast/Panhandle mid next week.
...Weather/Hazards Highlights...
Precipitation should be ongoing over the weekend as surface low
pressure consolidates in/near the Gulf. This provides support for
precipitation, with moderate to locally heavy amounts likely from
the Kenai Peninsula into Southeast Alaska for the weekend and
maybe lasting into Monday. Northerly to northwesterly winds on the
backside of the low could be brisk to strong across much of this
same region for the weekend until the low weakens early next week.
Precipitation will wane somewhat Tuesday-Wednesday, but increase
again, especially for parts of the Southeast by the middle of next
week.
Slightly above normal temperatures on Monday should moderate back
to or slightly below normal as mean troughing establishes over
the Mainland. The southern Coast/Southeast/Aleutians area should
remain below normal much of the period.
Santorelli
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