FXAK02 KWNH 152158
PMDAK

Alaska Extended Forecast Discussion
National Weather Service College Park MD
558 PM EDT Wed Apr 15 2026

Valid 12Z Sun 19 Apr 2026 - 12Z Thu 23 Apr 2026


...Southern Alaska Heavy Precipitation and Wind Threats...


...Guidance Evaluation/Preferences...

Forecast clustering has improved with latest guidance, seemingly
increasing predictability though average levels for medium-range
time scales for systems affecting Alaska as well as the upstream
approach to the south of the state of a deep extratropical low
associated with current West Pacific Typhoon Sinlaku to monitor.

WPC product continuity is better than expected given recent
massive guidance sensitivities as mainly derived from a blend of
best clustered guidance of 12 UTC GFS/ECMWF models and GEFS/ECMWF
ensemble means with emphasis slowly transitioning from the models
to the ensemble means over time in an effort to mitigate system
variance as consistent with individual predictability.

...Weather/Hazards Highlights...

The carving of a well established northern stream upper trough
over the western Mainland will provide cooling and periodic snow
showers from the Interior to the Alaska Range over the next week.

Meanwhile, a deepened low pressure system will slowly weaken over
the southern Bering Sea this weekend, but will remain a maritime
threat while also bringing periods with gusty winds and wrapping
precipitation out from the Aleutians into Southwest Alaska and
the Alaska Peninsula. Eastward progression of upper level trough
energy will also bring surface triple point low genesis and an
associated downstream return moisture flow will fuel a multi-day
periods with moderate to heavy precipitation and enhanced winds to
especially SouthCentral, but also Southeast Alaska into early-mid
next week. This includes a heavy snow threat for the Alaska Range
and also some potential gap wind enhancement with system passage.

It also remains noteworthy that a deep/moist extratropical low
associated with current West Pacific Typhoon Sinlaku slated to
track to the south of the state early-mid next week has the
potential to lift into the Gulf of Alaska and impact the state
later next week to monitor.


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