870
FXAK68 PAFC 231206
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
406 AM AKDT Sun Jun 23 2024

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

Another warm day is expected over Southcentral with near Red Flag
Conditions for Hot Dry and Windy expected again in the Copper
River Basin and the Susitna Valley. Temperatures today are
expected to again reach the 70s and lower 80s in inland areas and
generally in the 60s along the coast. Northerly winds are expected
again today over the Susitna Valley and Copper River Basin and
will likely bring in some smoke from large wildfires burning south
of Fairbanks. The smoke may push as far south as the MatSu Valley
and may trim off a few degrees as compared to yesterdays` high
temperatures. A thermal trough over the Copper River Basin and
Susitna Valley will again produce gusty winds and combined with
minimum relative humidity levels dropping to around 25 percent
this afternoon will produce near Red Flag Conditions in the
Susitna Valley and the Copper River Basin. A weak shortwave
rotating around the southern edge of an upper level high pressure
ridge sitting over the interior will be the focus for isolated wet
thunderstorms this afternoon that will build over the Talkeetna
and Chugach Mountains and then drift west over the Mat-Su and
Susitna Valleys, Anchorage and the western Kenai Peninsula. Monday
and Tuesday will see continued afternoon and evening showers and
thunderstorms, especially over mountainous areas.

&&


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

Sunday begins a slight cooling trend for the first half of the
week across Southwest Alaska beneath broken cloud cover. As the
trough currently over the region begins to meander southward,
breaks in cloudcover will allow continued late afternoon/evening
showers and thunderstorms across the Middle Kuskokwim Valley and
Western Alaska Range.

Slightly cooler temperatures are expected for areas south of
Dillingham on Monday, but overall conditions will be very similar
to Sunday, with afternoon instability and a chance for scattered
thunderstorms into the early evening. An upper level trough and
associated vorticity begin to weaken and move south into the North
Pacific Monday afternoon.

Looking west, model agreement is improving concerning the arrival
of the next upper low into the Western Aleutians on Monday
afternoon. This low will deepen into the 975 mb range while
tracking just north of the Central Aleutians into Tuesday. Expect
widespread showers across the Western and Central Aleutians on
Monday with small craft easterly winds overspreading the region
Tuesday, strengthening into widespread gales along the Southwest
coast by Wednesday morning.

&&

.LONG TERM FORECAST (Days 4 through 7: Wednesday through Saturday)...

The long term consists of a high amplitude ridge over the AlCan
border and a high amplitude trough over the Bering. This will lead
to fairly bimodal weather between the Bering/Southwest and
Southcentral. In general, the Bering and Southwest will be wetter
and cooler than what has been observed recently as a series of
shortwaves move from the Bering and into Southwest Alaska and the
west coast. Southcentral will likely be cloudier in this pattern,
though influence from the ridge will keep temperatures above
average with possibilities of breezy conditions and thunderstorms.
The main uncertainty in the forecast for Southcentral will be how
far east the shortwaves are able to make it, and therefor the
extent of convection and rain.

-Jones

&&

.AVIATION...

PANC...VFR conditions will persist through the TAF period. Light
and variable winds will pick up out of the south and southeast
through the afternoon. Winds become light and variable again late
tonight and into Monday morning. The best chance for showers and
perhaps a thunderstorm is late this afternoon into the evening
hours coincident with the strongest day-time heating and
instability. While most storms are expected to stay near the
higher terrain, there is a chance, with the aid of easterly flow
aloft, for a storm or two to advect off the Chugach Range and into
Anchorage. Shower and thunderstorm activity will die down over
night with the loss of instability. Monday afternoon also features
a chance of showers and storms, but confidence and probability
remain low at this time if a storm makes it off the high terrain
and into town or the terminal.

&&


$$