818
FXAK68 PAFC 131317
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
517 AM AKDT Sat Jul 13 2024

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

An upper level low stalls over Southwest Alaska providing
continued cloudy and scattered rain shower conditions for the next
several days across Southcentral. Southwest flow is bringing
ample moisture to the region. Some of the heaviest precipitation
on radar this morning is oriented along Cook Inlet into the
Susitna Valley and along the coast. At the surface, strong and
gusty south and east winds are moving through the Portage Valley
Turnagain Arm and southerly winds through the Copper River. An
easterly barrier jet is set up along the Gulf Coast and will
continue to increase to gale force with gusts to 50 kts possible
through this morning. Winds through the gaps and along the coast
are expected to gradually decrease later this afternoon and
evening as the front lifts inland. The Copper River winds will
strengthen again Sunday afternoon and evening with gusts to 30 mph
possible.

Most areas across Southcentral this morning are receiving
rainfall. Chances will continue to increase throughout the day for
the Copper River Basin. QPF for the Basin will be up to a couple
tenths of an inch through Sunday morning. Most areas along the
road system will see one third to three quarters of an inch during
that timeframe. The highest amounts of precipitation will be
along the mountains of the Susitna Valley, western Cook Inlet, and
Prince William Sound. Cordova and Whittier could see between two
and three inches of rainfall. Precipitation chances will be low
this weekend for Kodiak as the front lifts north today.

Despite the model consensus for the upper level low to linger
over Southwest Alaska through midweek, there are some differences
in the finer details for the locations where precipitation will
set up. None the less, a shower regime with southerly gap winds
will likely continue for Monday and perhaps Tuesday.

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)...

The forecast remains on track for the Southwestern mainland to
remain rather unsettled over the short-term period. A large Bering
Sea upper-level low will move over Southwest Alaska during the day
Saturday and sit and spin along the Yukon-Kuskokwim Delta through
the day on Monday. Numerous shortwaves will rotate around this
broad low and keep the mainland rather cool and showery through
Monday.

As the low drops south, an are of small craft winds on the
southern edge of they low will push into Bristol Bay, generating
waves from 7 to 11 feet. Similar conditions are expected for the
Pribilof Islands. Additionally, the Pribilofs will also see light
showery activity to contend with through the weekend and into
Monday with shortwaves rotating through on the backside of the
broad upper low over southwest.

&&


.LONG TERM FORECAST (Days 4 through 7) Tuesday through Friday...

An upper level closed low over Western Alaska weakens as it
slides across into the Gulf of Alaska by the end of the forecast
period. A second upper level low moves out of Eastern Asia into
the Western Bering near the Aleutians by Friday. A weak upper
ridge holds over the Eastern Interior through the end of the
week. Several troughs moving with the upper level jet support to
the South of the Aleutians through the pattern across the
Aleutians support surface features that brings showery weather
over the Aleutians and Bering. The Western Alaska low center
spreads showers across the Southwest, Alaska Peninsula and Kodiak
Island. Breezy gap winds through Shelikof Strait and Cook Inlet
diminish by Wednesday. Heaviest precipitation occurs ahead of the
Gulf low over the coastal zones from Prince William Sound to the
Canadian Border, and into Southeast Alaska. Areal rainfall eases
from West to East through Friday. Lesser amounts of lighter
rainfall spreads inland to the Alaska Range through the week.


- Kutz

&&.AVIATION...

PANC...Conditions could dip into MVFR in heavier rainfall. Expect
light northerly winds today. Tonight, ceilings will lower and
winds will shift southeasterly as southerly flow in Cook Inlet
and Turnagain Arm bend winds into the terminal.

&&


$$