033
FXAK68 PAFC 040031
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
431 PM AKDT Wed Jul 3 2024

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

An upper level ridge will continue to provide calmer weather for
most of Southcentral through most of the day tomorrow. However,
the nicer conditions over the 4th of July will quickly become
unsettled as a frontal boundary sweeps over the region. Widespread
rainfall is expected for most locations, however the rainfall is
expected to be light due to the influence of dry westerly flow
aloft. The front will pass over the Alaska Range by mid-afternoon
tomorrow before exiting the region Friday afternoon. Models
continue to slow down the main band of rainfall over Southcentral,
with Anchorage and the Mat-Su likely not seeing any drops until
the evening hours. In addition, a building pressure gradient over
the Copper River Basin will likely result in gustier conditions
for that portion of the forecast area starting tomorrow evening
and continuing into Saturday.

As the front exits off to the east on Friday, most lower elevation
locations will see a break from the rain as weak ridging tries to
build back over southern Alaska. Unfortunately, this break in rain
won`t last long as a deep upper level trough in northwest Alaska
begins to dig towards Southcentral. The placement of this trough,
as well as the trough currently located in the Gulf, will result
in a convergence boundary of southwesterly flow forming along the
southern portion of the forecast area. This will produce a
widespread and heavier rainfall event in comparison to the one
expected to occur tomorrow and looks to persist through at least
Saturday night. While the exact placement of this convergence band
is still begin contested in current model guidance, all models
are depicting a strong rainfall event to occur over the area. This
pattern setup will also result in widespread cloud cover for most
locations, as well as a brief cool down for the first half of the
weekend.

-BS

&&


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

High pressure ridging extends over Southwest Alaska, promoting
dry conditions for the rest of today. A front extending off a
Kamchatka low stretches across the central Aleutians and Bering
sea that will eventually feed into a shortwave dropping south into
Southwest Alaska early Thursday morning. There is a decent
moisture feed that will pull into Southwest, bringing widespread
wetting rain showers on Thursday and Saturday.

&&


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

The long range models are in more agreement today with the
pattern change mentioned in previous discussions. The areas of
high pressure that have been persistent over the Bering Sea and
the Gulf of Alaska in the early part of the period will start to
break down allowing a North Pacific low to track northward into
the Gulf. This combined with troughs of low pressure transiting
across the Bering Sea and Kuskokwim Delta will track eastward
across the region through the end of the period. As a result,
expect scattered precipitation and cooler temperatures across the
much of the forecast area. Additionally, gusty winds and possible
small craft conditions are expected in Cook Inlet and coastal
regions of the Kenai Peninsula Saturday afternoon and into Sunday.

-DD

.AVIATION...

PANC...VFR conditions and light winds persist through tomorrow
morning. Westerly winds begin shifting southerly this evening as
Turnagain Arm winds strengthen ahead of an approaching front.
Southerly to southeasterly winds then increase by late Thursday
morning, with the potential for gusts 20-25 kt persisting through
the afternoon.

Light rain is expected late Thursday afternoon through Friday
morning, with minor uncertainty in timing. Ceilings will drop with
this rainfall, likely below 5000 ft, with some guidance even
dropping ceilings to IFR.

&&


$$