195
FXAK68 PAFC 220114
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
514 PM AKDT Tue May 21 2024

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

The active weather pattern continues through the duration of the
short term, with a period of drier weather possible on Thursday
before another wave of precipitation arrives.

Satellite and radar imagery as of the time of writing depict a
frontal band currently moving across Southcentral Alaska.
Alongside widespread precipitation, this system is also bringing
with it gusty conditions for much of the area, particularly parts
of Turnagain Arm. The progenitor of this front is a vertically-
integrated low currently situated almost directly over St. Paul
Island, and which has reached a respectable depth of 522
decameters (500 mb) per operational guidance. The system will
begin to occlude as it meanders NE towards Nunivak Island,
ultimately falling apart through the day on Wednesday.

Its associated front will continue to maintain widespread chances
of precipitation through Wednesday, though some drying could
reach places like Kodiak Island. The front will depart through
Wednesday night, and drier weather is likely on Thursday,
particularly for areas north of the Kenai. Another wave will
advance north through late Thursday into Friday, bringing
widespread precipitation back across Southcentral.

&&


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

An occluded low is sitting just east of the Pribilof Islands this
afternoon and is the immediate focus of all the weather in
Southwest Alaska and the Bering Sea/Aleutian region. The main
front associated with this low passed through Southwest Alaska
earlier today, but the cold air aloft and moist southerly flow
behind the front is keeping stratocumulus clouds over most of the
region in spite of the frontal passage. The main low will move
slowly eastward and weaken, finally lifting northward as a warmer
low moves into the Bering Sea for Wednesday night and Thursday.
This will bring in another round of widespread showers to
Southwest Alaska. Places along the Kuskokwim Delta coast have been
cold enough to see some snow mix in with the rain today. There
may still be some snow that mixes in this evening and overnight,
but in general warmer air from the southwest will move over the
area and the areas of snow will retreat northwestward across the
Bering Sea over the next day or two. The Pribilof Islands could
see a little snow mix in with the rain on Wednesday night.

The second low will enter the western Bering near Attu Wednesday
evening and then track between the Pribilof Islands and Nunivak
Island Thursday night. As mentioned earlier, this low is much
warmer aloft than the current low. There will still be showers
around this low, especially when it moves over Southwest mainland
Alaska, but the heaviest showers should be associated with the
embedded waves that will develop around this low. Overall, total
precip amounts should be less with this second system.

&&


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

The Eastern Bering upper level low continues to ooze its way
Southeastward across the Alaska Peninsula, into and across the
Gulf of Alaska through the beginning of the week. A rather
energetic impulse over Northwestern Alaska helps flatten a Western
Bering ridge, and draw a trough back into the Bering through the
weekend, and helps establish a link-up with a second low out of
the Russian Far East through Tuesday. With smaller troughs and
weak surface low centers rotating through the pattern along the
Aleutians, periods of rainfall are expected over the Aleutians,
AKPEN, Kodiak Island and the Southern Kenai Peninsula through the
forecast period.


- Kutz

&&
.AVIATION...

PANC...VFR conditions expected through the TAF period, elevated
easterly sustained winds and gusts will slowly decrease through
tonight, subsiding to to 6-12 kts under scattered to overcast
skies with intermittent ceilings around 5k ft. Reinforcing
mid/upper level trough will bring a windshift and the potential
for -RA near end of TAF period.

&&


$$