060
FXAK68 PAFC 141335
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
535 AM AKDT Sun Jul 14 2024

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

Upper level low pressure center is continuing to linger over
Southwest Alaska with southerly flow directed towards
Southcentral. Moderate to heavy rainfall from yesterday is
tapering off this morning for Kenai Peninsula, Anchorage, and the
Susitna Valley with the system moving east. There may not be much
of a break in rainfall however as widespread scattered showers
will last through this afternoon. The driest locations will be
Kodiak and the Copper River Basin. Another shortwave trough will
once again bring steadier rainfall this evening. The highest
chances for precipitation will be near terrain with upslope flow,
especially near the coast and Susitna Valley where half inch to
around one inch of additional precipitation is possible. A band of
precipitation could set up from the western Kenai to Anchorage to
the Matanuska Valley, but models have continued to struggle with
the details on where any banding would set up along with the
timing. Around a tenth to half of an inch of additional
precipitation is possible for most locations over the next 24
hours. Turnagain Arm winds and Copper River winds return by
afternoon as southerly flow continues for Southcentral. Finally,
model consensus degrades substantially in time and low confidence
with the details in the forecast persists. Generally though,
expect mild temperatures and showery conditions likely to continue
over the next few days as multiple troughs round the Southwestern
Alaska low.

&&


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

The Bering low tracks over Southwest Alaska today, cycling
numerous shortwaves over the Mainland through Tuesday. Conditions
overall will be mostly cloudy, showery, and cool. Areas of small
craft winds and waves are expected to push into Bristol Bay
through this evening. Wave heights are expected to be on the
order of 7 to 10 feet. While the westerly fetch is expected to
continue into Monday, winds will diminish late tonight and wave
heights will also start to subside by then as well. A potentially
stronger and more moist system could move towards the western
Aleutian Chain by Wednesday, but confidence is low on the ultimate
track, strength, and evolution of the system at the moment.

&&


.LONG TERM FORECAST (Days 4 through 7: Wednesday through Saturday)...

By the middle of the week, the upper level low (the same one
currently bringing widespread rain to Southern Alaska) will be
situated over Southwest and Southcentral Alaska. This low will
then slide slowly to the southeast into next weekend. An upper
level ridge looks increasingly likely to briefly build into
Southwest Alaska for the end of the week as well. What this means
for the weather is that, in general, there should be a drying
trend toward the end of next week.

Even by Wednesday the Kuskokwim Delta may have made the shift to
the rain ending while the Bristol Bay region of Southwest may
still see some showers before the low pulls southeastward. For the
latter half of the week most of Southwest Alaska should see
noticeable warmer and dryer conditions.

Southcentral will continue to see areas of rain on Wednesday with
those area also pulling southward after that. The challenge for
grater clearing for Southcentral is that while the upper low
itself moves into the eastern Gulf, the trough will still extend
northward toward the AlCan border for the second half of the week.
this will also usher in an elongated front to the north Gulf
coast late Thursday or Friday. There may also be an easterly wave
or two that gets caught into the easterly upper level flow and
bring rain to the Copper River Basin. All these possibilities with
the upper level ridge remaining to the Southwest will make it
more difficult for Southcentral to clear out as well as Southwest.
All that said, it bears watching to see the details of this
system as it tracks through the Gulf and see whether it brings
more showers in easterly waves or more clearing than is currently
expected.

&&

.AVIATION...

PANC...Conditions are expected to improve into the early
afternoon as rainfall tapers off and showers linger across the
area. Another round of rainfall will return later tonight though
that may lower conditions to MVFR in rainfall again at that time.
Timing of precipitation and ceilings continue to be a challenge.
Southerly winds are expected later this morning over the terminal,
but gusty winds from Turnagain Arm will ramp up tonight and
linger through Monday.

&&


$$