Wildfire in Alaska, May 26 to 28, 2022

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
448 PM AKDT Wed May 25 2022

.ANALYSIS AND UPPER LEVELS...

The pattern for the remainder of the week is beginning to take
shape. Water vapor satellite shows ridging becoming established
over the central Bering Sea. Northerly flow streaming around the
east side of the ridge is pushing the previous weak trough further
offshore away from Southcentral Alaska. As the ridge builds in,
clearing of most lower level clouds has happened, with only high
cirrus streaming overhead. The marine layer stratus made it's
first widespread appearance of the year, developing across most of
Cook Inlet this morning, however daytime heating is mixing it out
quickly. Over the Bering Sea however, the marine layer is very
established, and building toward the mainland as high pressure
strengthens.

&&

.MODEL DISCUSSION...

Guidance is in great agreement on the evolution of the upper level
ridge through Saturday. Some difference begin to arise as a
disturbance in the northern Pacific begins to amplify the flow on
Sunday/Monday. However, guidance is in good agreement of a
strengthening low pressure system approaching the southwestern
Gulf of Alaska. Confidence is higher than normal.

&&

.AVIATION...

PANC...VFR conditions and light winds will persist. However,
marine layer stratus is expected to develop in Cook Inlet
overnight and will approach close to the terminal by the morning
hours.

&&

.FIRE WEATHER...

A fire weather watch has been issued for Friday/Saturday for
multiple areas around Southcentral, and additionally the Greater
Bristol Bay area. The building ridge over the Bering
Sea/Southwest mainland continues to be a concern bringing in the
warmest temperatures of the season, coincident with a drying air
mass. Winds will be close to meeting criteria. Given the
confidence in the hot and dry portion, and the increase in holiday
weekend recreation an early watch seems prudent.

&&

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

An upper-level ridge will build eastward over mainland Alaska
through the end of the week. Weak upper-level shortwaves
propagating through the flow from north to south along the
periphery of the ridge will bring a slight chance of showers each
afternoon and evening, mainly for the higher elevations
surrounding the Copper River Basin.

With the ridge strengthening over the region, expect a general
warming and drying trend through the remainder of the week and
into the start of the Memorial Day weekend. Temperatures will push
to around 70 degrees on Thursday for most inland locations, with
temperatures rising to the mid-to-upper 70s for parts of the Kenai
Peninsula, Mat-Su Valleys, Anchorage Bowl, and Copper River Basin
by Friday and Saturday.

A weak upper-level trough is expected dive southward across
Southcentral on Friday and make for potential fire weather
concerns. This feature looks to bring in the potential for an
increase in winds Friday afternoon and evening, with warmer
temperatures allowing for stronger flow aloft to mix 15 to 20 mph
gusts to the surface during the afternoon and evening hours. The
combination of forecast temperatures in the 70s, gusty winds, and
a drier airmass could drive relative humidity values down to 20%
or lower from the Susitna Valley south to the Kenai Peninsula.
Typical diurnal sea breeze patterns are also expected to be
overcome by northerly flow dominant throughout the atmospheric
column on Friday, which will limit moisture even near the coast.
As a result, this potential for hot, dry, and windy conditions
going into the holiday weekend has prompted a Fire Weather Watch
Friday morning through Saturday evening.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3: This
morning through Friday night)...

A ridge of high pressure is gradually building back into
Southwest from the northern Bering this morning. The ridge will
help to keep surface winds relatively light and variable, with a
warming trend expected through the weekend. Morning satellite
reveals areas of stratus moving through the Lower Kuskokwim Valley
into the Kuskokwim Delta with fog observed in Bethel, and a
second area of stratus inland of the Bristol Bay coast. Much of
this activity should begin to clear with the onset of daytime
heating, resulting in a favorable day for outdoor activities. By
Friday, hot and dry conditions will become more prevalent across
the Lower Kuskokwim Valley with high temperatures approaching 75
degrees Fahrenheit. The next passing shortwave disturbance around
the ridge will also bring increasing winds to the region with
potential gusts approaching 25 mph. Thus, conditions will need to
be monitored closely in the event that fire weather thresholds are
met.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3: This
morning through Friday night)...

Marine stratus and areas of fog blankets the Bering this morning
while a broad ridge of high pressure sits centered just west of
the Pribilofs. The ridge will be slow to budge over the next
couple of days with benign sea conditions forecast. By Friday,
however, a front will begin to approach the Western and Central
Aleutians from the south with small craft easterly winds
developing. Similarly, the next shortwave trough will move
southward across Southwest on Friday with northerly small craft
winds forecast to develop over Bristol Bay into the Alaska
Peninsula.

&&

.MARINE (Days 3 through 5: Saturday through Monday)...

Gulf of Alaska - A weak trough collapses over the North Gulf
Coast, as high pressure moves across the the Gulf through Monday.
Forecast confidence is good. Moderate Westerly winds extend from
the Alaska Peninsula into the Central Gulf, and East of Kodiak
Island, diminishing late Sunday. Seas less than 10 feet.

Aleutians / Bering - The Bering high slides into Western Alaska
through Monday. A Kamchatka low and front sweep over the Western
Aleutians through Monday. Forecast confidence is fair due to the
speeds of movement of the low and front. Gusty Northerly winds
over the Eastern Bering and Bristol Bay, diminishing Sunday.
Moderate Easterly winds extend across the Southern Bering through
Monday. Seas less than 10 feet.

&&

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

A weakening Kamchatka low and front moves over the Western
Aleutians and dissipates in the North Pacific for Tuesday. The
main map feature is the broad ridge covering most of the Bering
and extending into Interior Alaska through Wednesday. Compared to
earlier model runs, the EC and GFS extend a moderated ridge more
North than East, stopping short of the Yukon border. The Canadian
model holds its strength further West. Forecast confidence
decreases with a slight chance of showers associated with a
thermal low in the Eastern Interior. A well developed North
Pacific low moves into the Western Gulf for Tuesday, changing in
the overall pattern, and spreading moderate winds and increasing
clouds and rain across Southcentral Alaska through midweek. To the
West, a well developed North Pacific low complex pushes toward
the Aleutians through Wednesday, bring windy conditions with low
clouds and rain spreading into the Bering.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Flood Advisory: 141.
MARINE...NONE.
FIRE WEATHER...Fire Weather Watch: 101 111 121 145 162.

&&

SYNOPSIS AND MODEL DISCUSSION...ML
SOUTHCENTRAL ALASKA...CQ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...RC
MARINE/LONG TERM...KZ/ED