351
FXAK68 PAFC 071338
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
538 AM AKDT Sun Jul 7 2024

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

The upper level pattern still has the 500 mb trough situated over
Southwest Alaska which is keeping Southcentral in moist
southwesterly flow aloft. While the front that brought some
rainfall to most of the region yesterday has moves into the
northern Gulf, the airmass remaining over Southcentral is very
moist. The gusty winds are diminishing and should have settled
down fully by late this morning for the Copper River Basin and
through Turnagain Arm. This upper level trough will dig into
Southcentral tonight into Monday and could bring a little more
rain in at that time. However, it will move through the area as
it will merge with an upper low moving northward over the Gulf of
Alaska and basically remain over Southcentral through the middle
of the week. This will keep the cool and cloudy weather going.

&&


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

Areas of low stratus and fog are persisting across the Bering and
Southwest Alaska this morning. Weak high pressure resides over
the region wedged between a broad upper low anchored over the
Beaufort Sea and a second upper low roughly 500 nautical miles
south of Kodiak Island. The dry but cool pattern should prevail
today and tomorrow across Southwest Alaska with light onshore
winds. By Monday the pattern begins to change with the arrival of
a shortwave trough into the YK Delta. Rain chances are forecast to
expand in coverage from north-to-south as the trough eventually
overspreads Southwest Alaska by Monday night. Tuesday will see
widespread showers as the trough pushes into interior Alaska and a
front sags southward into the entirety of the Aleutian Chain.

To the west, a quick look at satellite imagery reveals the
presence of a compact low situated between Kamchatka and the
Western Aleutians. A warm front extends from the low the into the
Western and Central Aleutians where a mix of fog and drizzle is
being observed in Adak and Shemya. The low will shift across the
Central Aleutians on Monday with a temporary uptick in light
showers over the Central and Eastern Aleutians. Shower activity is
renewed on Tuesday as the low connects with the southward moving
front across the Aleutians.

-BL

&&


.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.

.AVIATION...

PANC...MVFR ceilings near/just below 3000 ft will persist through
Sunday afternoon with scattered light showers in the area. Gusty
southeasterly winds will continue to diminish through Sunday
morning, but may return Sunday evening, albeit not as strong as on
Saturday.

&&
$$