158
FXAK68 PAFC 290058
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
458 PM AKDT Fri Jun 28 2024

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

Southerly flow across Southcentral is allowing for more moisture
and a larger extent of cloud cover to spread across the area.
Portions of the Copper River Basin near the eastern Alaska Range
is clear enough for convection to get going this afternoon.
Thunderstorm extent is expected to be more isolated over the next
couple days. Kodiak continues to be moving through periods of
light rain and fog as a front remains stationary in the western
Gulf that extends into the Bering Sea.

With the Bering low sinking south and the Alaska Canadian ridge
retreating north and east, flow will shift southeasterly on late
Saturday and Sunday. An weak trough looks to lift northeast
through the Gulf and across the southern Kenai Peninsula. This
would increase precipitation potential for Kodiak and the Gulf
coast of the Kenai Peninsula. With southeasterly flow, western
Kenai Peninsula, Anchorage, and the southern Susitna Valley could
be dry due to downsloping flow. Seward could see around a tenth of
an inch of rainfall with reasonably high confidence, but Kodiak
has moderate to lower confidence on QPF. Totals have trended a
little bit higher for Kodiak with three-quarters to an inch
possible over the weekend. Away from the Southcentral coast,
rainfall is more likely than it recently with widespread scattered
showers likely for northeast Prince William Sound, Copper River
Basin, and northern Susitna Valley. A few lightning strikes cannot
be ruled out for the Talkeetnas, northern Wrangells, and eastern
Alaska Range early Sunday afternoon as an easterly wave embedded
into the ridge could quickly pass through. Models hint at some
instability during this time that could help, but any convection
would depend on the timing of the easterly wave and daytime
heating with potential cloud cover. Midlevels do appear a bit
cooler though. Gusty winds to around 20 mph is possible through
south and southeast gaps for Sunday, particularly the Copper River
Valley and Turnagain Arm into south and west Anchorage.

The Bering low will continue to dip south of the Gulf into the
North Pacific early next week. High pressure remains over the
mainland though and chances of precipitation will remain in the
forecast for Monday and perhaps Tuesday. There is more uncertainty
in the synoptic pattern towards midweek where the weather would
highly depend on the timing and position of the low, the north to
south shift of the ridge over the mainland, and how far south a
(potentially) embedded trough along the ridge moves through
Southcentral.

rux

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA, THE BERING SEA/ALEUTIANS
(Days 1 through 3: This afternoon through Monday afternoon)...

Very few changes were made to the forecast. A broad upper-level
low over the Bering Sea will continue to produce unsettled weather
for much of the Aleutian Islands and Southwest coast into the
start of the weekend. For the interior portions of Southwest,
building high pressure will result in warmer and drier conditions
through the forecast period. Afternoon showers are possible over
the interior, including the Western Alaska Range, eastern portions
of the Lower Kuskokwim Valley, and along the Aleutian Range in
interior Bristol Bay. However, the stable air mass from the ridge
over the region will limit the potential for thunderstorm activity
through at least Sunday.

A shortwave passing along the Aleutian Chain is gradually
combining with the aforementioned upper low. The resulting new
surface will continue tracking along the Chain towards the AKPen
and eastern Bering, where it looks to linger starting Saturday
morning. This shortwave low will again produce rounds of
precipitation for much of the eastern Bering/Aleutians and
Southwest coast, lasting through the weekend. The low will begin
to weaken by the afternoon hours on Sunday as a building ridge of
high pressure enters the western Bering and pushes eastward,
tapering off most remaining precipitation behind the low as it
does so. For Monday, expect the ridge to dominate the
Bering/Aleutians as it nudges further into Southwest Alaska.

-AF/BS

&&

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

Low pressure in the Eastern Gulf of Alaska will slowly track to
the east producing unsettled weather across the Gulf. A ridge of
high pressure will continue to dominate South Central Alaska and
the Copper River Basin throughout the period bringing warmish
temperatures and dryer conditions over the region. Isolated to
scattered thunderstorms are possible along the Alaskan Range and
Copper River Basin through Friday afternoon.

-DD

&&

.AVIATION...

PANC...VFR conditions and generally light southwesterly winds
will persist. A slightly stronger wind out of the SSE out of the
Turnagain Arm may brush the airport early this evening and again
on Saturday, but current thinking is that it`ll remain on the
weaker side.

-Brown

&&
$$