Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
642 PM EDT Thu Apr 17 2025

Valid 12Z Mon 21 Apr 2025 - 12Z Fri 25 Apr 2025

...General Overview...

It generally remains the case that the next organized storm
system over the central/western Aleutians in the short range will likely
track in the general direction of the Alaska Peninsula early next
week, bringing more rain/mountain snow and gusty winds. Ahead of
this storm will likely be a building ridge axis from the Gulf to
the Interior, while a strong Arctic surface high and polar
easterlies continue from the Brooks Range northward. An upper
trough is likely to become established over the Gulf into the
middle through later of next week.

...Guidance/Predictability Assessment...

Favor a composite blend of well clustered guidance of the 12 UTC
GFS/ECMWF/UKMET/Canadian models as valid Monday and Tuesday. This
solution has good ensemble support in a pattern evolution with
seemingly above normal predictability. Manually adjusted the blend
to include marority weighting of the 12 UTC GEFS/ECMWF/Canadian
ensemble means at longer time frames amid growing forecast spread.

...Weather/Hazards Highlights...

Attention turns to the Aleutians storm by Sunday and into early
next week with southerly flow advecting moisture towards the
terrain of the Alaska Peninsula, and eventually Kodiak Island and
the Kenai Peninsula. This does not appear to meet hazardous level
criteria for now, but this will continue to be monitored in the
days ahead. Expect additional moderate precipitation chances will
peiodically work into coastal areas of SouthCentral and Southeast
Alaska through mid-later next week as moisture wraps around the a
mean low position over an unsettled/windy Gulf of Alaska.

Temperatures are expected to be near to above average across
central and southern portions of the mainland, and below average
across the Brooks Range and to the Arctic Coast where the Arctic
high will have more of an influence on the weather. There will
likely be strong polar easterlies in place across northern Alaska,
and even though winds are not expected to reach hazardous
criteria, periods of blowing snow are possible.

Upstream, there is a growing guidance signal indicating that the
next organized low pressure system and enhanced wrapping rain and
winds will work to the Aleutians by midweek. This system and
associated weather focus has the potential to subsequently work
again toward the southeast Bering Sea and the Alaska Peninsula and
vicinity later 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