620
FXAK68 PAFC 070034
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
434 PM AKDT Sat Jul 6 2024

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

Widespread rainfall continues to take place over Southcentral this
afternoon, with places near the Talkeetna Mountains and Gulf
coast getting the heaviest rain at the moment. The heaviest rain
will begin to taper off through the evening and become mostly
light rain by Sunday morning. Southwesterly flow will continue
through at least the early part of next week, allowing for upslope
precipitation to take place along all of the western facing
mountainsides. Widespread cloud cover will also continue,
resulting in cooler temperatures persisting for much of the area.

Another round of widespread rainfall is expected Monday afternoon
as multiple shortwaves from upper lows in both the Bering and Gulf
interact over southern Alaska. Locations near the Talkeetna
Mountains and Alaska Range are currently expected to get the most
rainfall, while lower elevation areas along the Copper River
Basin could get little to no rain due to downsloping.

The next event of concern will occur late Tuesday as a strong
shortwave low from the Bering moves eastward into central Alaska,
in addition to the upper low in the Gulf shifting northward
towards the coastline. The shortwave low will move over southwest
Alaska during the day on Tuesday before stalling near the Alaska
Range, producing widespread heavier rain for most of that part of
the state. Some spillover precipitation may take place for areas
north and west of Cook Inlet, though downsloping could impact
precipitation rates at lower elevations. The upper low in the Gulf will
send a wave of rainfall over the coastline and into Prince William
Sound midday Tuesday, lasting well into the overnight hours.

While unsettled weather is expected to continue into the
foreseeable future, winds across most of the area will become
much calmer by Sunday morning due to the pressure gradient over
Southcentral starting to weaken tonight.

-BS

&&


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


Satellite images this morning and afternoon show a trough digging
into the Central Aleutians with surface observations reporting
fog, low clouds and persistent north to northwest wind over the
area. Tomorrow, a ridge of high pressure over the Western
Aleutians begins to slightly flatten with the arrival of a
Kamchatka Low in the Bering Sea. This low will bring reinforcing
rain showers and low ceiling/fog conditions into tomorrow evening
as the low moves south through the Aleutians. Temperatures will
hold steady in the upper 50s/lower 60s today and tomorrow with
lows in the 40s across the Western and Central Aleutians. Small
craft wind gusts will accompany the low`s track.

Elsewhere today, satellite images show a cold front with rain
showers over the Alaska Peninsula and portions of the Southwest.
These rain showers and northerly to northeasterly moving clouds
will continue through tomorrow afternoon as a result of a
southerly winds from a stationary low due south of Sand Point in
the North Pacific Ocean. Northerly flow over the Kuskokwim Delta
and Alaska Range will continue to bring cloud cover and scattered
rain showers to the area through tomorrow evening. A fast moving
low from the North Bering Sea could bring a quick period of heavy
rain showers Monday evening into Tuesday to the Toksook Bay-Aniak-
Togiak area.

-DJ

&&


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

An Arctic upper level closed low center slips through the Bering
Strait and moves to the Yukon Delta by the end of the forecast
period. A second low center in the Gulf of Alaska merges with this
low to form a Bering-wide low, with a trough extending back
through the Gulf into the Eastern North Pacific. These two systems
continue to spread precipitation across the Southern Mainland and
Alaska Peninsula. A weak ridge holds onto the Eastern Interior
through Saturday. This helps dry out areas near the ALCAN border,
but also increases the risks for development of convective
activity through the week. Despite good agreements in the larger
scale features throughout the forecast, forecast spread and
uncertainty between models becomes problematic through the second
half of the forecast period. Longer term light precipitation will
cover from the Canadian border across Southwest Alaska and the
AKPEN, bringing some relief with forest fires. Expect brief
periods of heavier rainfall as the upper features move through the
pattern into the weekend, with gusty offshore winds developing
Saturday.

- Kutz

.AVIATION...

PANC...VFR ceilings below 5,000ft will persist from late afternoon
through the overnight hours. Expect additional lower cloud decks,
around 2,500ft, at times throughout evening and nighttime hours as
occasional showers move over the terminal. Heavier showers may
bring ceilings down to this 2,500ft level (MVFR) later this
afternoon. Shower activity is expected to taper off later this
evening.

Southeasterly Turnagain Arm winds will also persist across the
terminal through Sunday morning. Sustained winds and gusts have
likely already peaked, and will slowly diminish through the TAF
period. Gusts of 25 to 35 mph are still likely this evening
through around midnight. South winds will become light at around
10 mph by mid-morning Sunday as the frontal system finally slides
south over the northern Gulf.


&&


$$