489
FXAK68 PAFC 161348
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
548 AM AKDT Tue Jul 16 2024

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

The short term forecast remains largely unchanged. Southcentral
is expected to remain in an unsettled pattern through at least
Wednesday as an upper-level low lingers over much of the Mainland,
with various shortwaves rotating around the low. Expects several
periods of rain showers throughout the next several days. The
greatest chances for precipitation will be Prince William Sound
and up Cook Inlet through the Susitna Valley. Copper River Basin
will remain on the drier side as southerly winds persist through
the Copper River Valley. With the upper low trending more north
and winds shifting westerly in the Copper River Basin, Glennallen
area could see some light precipitation Wednesday afternoon.

The ridge over the CONUS has kept us in a fairly blocked pattern
with persistent, cool and wet weather over Alaska. Looking ahead
to the end of the week though, high pressure builds in from the
west and pinches off areas of low pressure to the north and south
of Southcentral Alaska. Should the trend continue with high
pressure building into the area and low pressure headed south,
conditions could trend relatively drier and warmer than the cooler
and wetter conditions we`ve seen for much of this month so far.

rux / Fenrich

&&


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

Overall, fairly benign weather expected as weak weather systems
move across Southwest Alaska, the Bering Sea, and the Aleutian
Islands over the coming days. Expect light to moderate rain and
rain showers, with minor uncertainty in rain timing and totals. As
a ridge builds over the Western Bering/Aleutians today and
transits eastward through Thursday, rain will taper off and give
way to fog and low stratus, especially in the Bering Sea and
Aleutians.

Diving into the details, an upper low is currently located near
Seward Peninsula. Weak shortwaves moving around it are currently
bringing spotty rain showers to Southwest Alaska. A more robust
shortwave moves into Southwest Alaska from Tuesday night through
Wednesday, bringing more widespread precipitation. There remain
some timing differences with this band of rain, leading to
uncertainty in overall rain amounts. The current forecast reflects
a slower arrival of precipitation, with the potential for rain to
arrive earlier on Tuesday/Wednesday if the faster scenario plays
out.

For the Bering Sea and Aleutian Islands, have increased rain
chances as a low skirts south of the Aleutian Islands and Alaska
Peninsula. As the ridge of high pressure increases in amplitude
Tuesday night into Wednesday, expect fog and low stratus to
develop along the Bering Sea and Aleutian Islands. Fog is
inherently difficult to forecast, so confidence is low in where
the fog may develop and how thick it may be. By Thursday, another
low moves into the Western Aleutians/Bering, bringing winds to
small craft speed and another round of rain.

-KC

&&


.LONG TERM FORECAST (Days 4 through 7: Friday through Monday)...

On the Alaska Weather map, an elongated upper level low extends
North to South through Interior Alaska. A closed low in the bottom
of this low near Kodiak Island weakens as it moves across and out
of the Gulf of Alaska for late Saturday. Over the Bering, a
somewhat broad ridge moves into Western Alaska on Saturday, and
links up with a Canadian ridge by Sunday. This reduces the
likelihood of rainfall over the West and Interior and brings in
some warmer temperatures. In the far Western Bering, another East
Asia low and front pushes into the Central Aleutians and Bering
through Monday. The associated front spreads locally heavy rains
and gusty surface winds less than gale force over the Pribilofs,
Aleutians and Bering through the beginning of the workweek.
Southwest Alaska and the Alaska Peninsula will have improving
weather conditions through the weekend. Model agreement remains
good through the period, with only the transient troughs and
shortwaves rippling through the pattern. Southcentral Alaska up to
the Alaska Range will see a lesser chance of wetting rainfall
over the weekend, but lingering showers across the coastal zones
remain with some onshore flow.


- Kutz

&&

.AVIATION...

PANC...MVFR/VFR conditions are expected through today as scattered
rain showers persist through this evening. Ceiling heights around
5000 feet are expected through this evening.

DJ

&&


$$