505
FXAK68 PAFC 301257
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
457 AM AKDT Wed Jul 30 2025

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today
through Friday)...

Widespread precipitation is expected today from the Western Kenai
Peninsula northward through the Mat-Su Valley and Anchorage as a
shortwave from the Arctic low to the north drops into Southcentral
AK the same time a wave from the Gulf low pivots northwestward.

Steady rain tapers off to showers late this evening. Elsewhere,
isolated thunderstorms are possible along the north and south
sides of the Wrangells for this afternoon into the evening hours
as there looks to be just enough instability in the eastern Copper
Basin, near the thermal low, to generate a few lightning strikes.

Showers will once again be possible across Southcentral for
Thursday as additional easterly waves move across the area from
Yukon, Canada. The best chances for isolated thunderstorm
formation will be across western portions of the Copper Basin,
along the Kenai Mountains, as well as along the Chugach Front
Range and Hatcher Pass. Forecast confidence decreases for Friday
mainly due to the timing and progression of a stronger easterly
wave rotating in from the Gulf. Friday does look to be wet across
the coast and eventually through the interior. However, the
question remains unanswered to this point whether steady rain
starts in the morning or holds off until the afternoon. Stay tuned
as we look to get a better handle on the Friday system.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days
1 through 3: Today through Friday night)...

Currently, a vertically stacked ridge of high pressure is
situated across the Eastern Bering Sea and into parts of Southwest
Alaska, bringing fog and low stratus to areas underneath it.
Aloft, the ridge is trying to break down as Southwest Alaska is
also feeling the effects of an Arctic trough of low pressure to
the north, bringing rain showers to the region today. Clearing
skies and warming temperatures are forecast for the Kuskokwim
Valley and inland Kuskokwim Delta for tomorrow afternoon and
Friday with temperatures rising into the 70`s. A favorable
environment could lead to some convective showers forming along
the western Alaska Range Friday afternoon.

An area of low pressure is moving into the Western Aleutians this
morning, bringing a swath of rainfall and gusty winds with its
front from Shemya to Atka. This low deepens and moves northward
into the Western Bering Sea by tomorrow morning as its front makes
progress across the Central Aleutians. A second low from the
North Pacific tracks into the Bering Sea Thursday night and merges
with the aforementioned system, bringing a stronger round of
southerly winds and rain to the Aleutian Chain and southern Alaska
Peninsula through Friday night. We will continue to keep a close
eye on this system as guidance improves in the coming days.

&&

.LONG TERM FORECAST (Days 4 through 7/Saturday through Tuesday)...

Starting with the extended forecast period on Saturday, the key
features will be a deep low/trough in the Bering Sea, ridging over
mainland Alaska, and an upper level low somewhere in the Gulf of
Alaska or Northeast Pacific. Model guidance varies with the exact
placement of each of these features, introducing some uncertainty
into the forecast right off the bat. Honing in on the most impactful
weather, a frontal system will track toward the Southwest AK coast
on Saturday. The GFS has been consistently further north with the
Bering trough and more aggressive in pushing the front onshore of
Southwest AK, bringing rain and strong southeasterly winds to the
nearshore coastal waters from the Kuskokwim Delta coast to Bristol
Bay. The Canadian/ECMWF as well as ensemble data supports a
further south low position with the front elongating and weakening
off the Southwest coast. The current forecast represents this
latter solutions, with the strongest winds just off the coastline
and less rain and wind pushing onshore. In any case, the remnant
low will sit over the Bering Sea and slowly weaken through
Tuesday. With cooler air aloft, do think the extent and severity
of low clouds and fog currently being experienced over the Bering
Sea/Aleutians/SW Alaska will greatly diminish for the extended
forecast period.

Meanwhile, model spread with the low in the Gulf grows quite large
by early next week. Starting Saturday, there is fairly high
confidence that short-waves rounding the top of the low will
track westward into Southcentral, but low confidence in exactly
where the most likely areas for rain will be. Despite the
radically different solutions for low placement on Monday, all of
the guidance indicates the low exiting eastward, which will lead
to mostly dry conditions across Southcentral and Kodiak Island.
Models are then completely out of phase with the upper level wave
pattern (placement of troughs/ridges), making it very difficult
to hone in on potential weather impacts.

-SEB

&&

.AVIATION...

PANC...Wind direction will continue to fluctuate between
southeasterly and southwesterly through the morning hours as a
Turnagain Arm wind weakens. Winds become light and northerly by
the evening. Skies will oscillate between VFR and MVFR during
periods of rainfall through this evening. More solidly VFR
conditions return by tonight/early Thursday morning when rain
chances diminish, but there is a possiblity of fog.

&&


$$