Red Flag Warning 13, NWS Anchorage, AK

361 
WWAK61 PAFC 120030
RFWAER

URGENT - FIRE WEATHER MESSAGE
National Weather Service Anchorage AK
430 PM AKDT Mon Jul 11 2022

AKZ145-120700-
/O.CON.PAFC.FW.W.0013.000000T0000Z-220712T0700Z/
Susitna Valley-
430 PM AKDT Mon Jul 11 2022

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM AKDT THIS
EVENING FOR LIGHTNING FOR THE SUSITNA VALLEY...

* Timing...Until 11 PM AKDT Today.

* Lightning Activity Level...4.

* Winds...South 5 to 15 mph. Locally higher gusts near 
  thunderstorms.

* Relative Humidity...40 to 50 percent.

* Temperatures...Mid to upper 60s.

* Impacts...Ample lightning could lead to numerous new fire
  starts. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A red flag warning means that critical fire weather conditions
are imminent or occurring now, or will shortly. It is directed
toward fire agencies, and through them to the public.

&&

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
437 AM AKDT Mon Jul 11 2022

.ANALYSIS AND UPPER LEVELS...

There are a few key features to note that will play important
roles in the forecast for the coming days. A low spins in the
eastern Gulf, whose trough extends up into Southcentral today.
Associated shortwaves are producing areas of increased instability
to portions of Southcentral, which will result in areas of wet
thunderstorms and rain showers. Over Southwest Alaska, upper level
ridging is in place and will track eastward over the next couple
of days. A separate low is dropping south across the Bering Sea
today and tomorrow before crossing over the AKPen and then pushing
into the northern Pacific. Its front pushes onshore over the
Southwest coast, however, the brunt of any associated
precipitation will likely remain over the AKPen and higher
elevations, including the Kilbuck Mountains and Western Alaska
Range.

&&

.MODEL DISCUSSION...

Models remain in good overall synoptic agreement through the short
term. There is better consistency with the shortwave dropping
south across Southcentral today, increasing confidence regarding
thunderstorms and convective activity across the higher elevations
of the Susitna Valley and the Talkeetna Mountains. There is a good
handle on the low drifting south across the Bering. The main
challenge with this will be regarding its front and associated
precipitation across Southwest tomorrow afternoon.

&&

.AVIATION...
PANC...VFR conditions and light winds will persist. A pressure
gradient building in later this afternoon will produce some gusty
Turnagain Arm winds for the evening and overnight hours. Winds
should come down again after midnight.

&&

.FIRE WEATHER...

Upper level riding moves over Southwest today, conditions will
begin to dry out and warm up. Northerly winds will also likely
pick up ahead of the ridge today, and will gradually diminish
through the evening and overnight hours. A shortwave moving across
Southcentral promotes increased instability, resulting in the
chance for wet thunderstorms across the Mat-Su Valley, Talkeetna
Mountains and the Chugach Mountains today.

&&

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

Shortwaves continue to move towards the Alaska Range and Susitna
Valley this morning which has produced a few thunderstorms near
the Alaskan Range mostly in Fairbanks area. While another
shortwave is bringing showers from near McCarthy and south to
Cordova this should continue today into Tuesday morning. More
showers and thunderstorms are expected to form along these waves
mainly over the higher terrain this afternoon especially across
the Talkeetnas and northern Susitna Valley as well as the northern
Copper River Basin. Some of these storms could move into the
populated valley areas especially from Big Lake and Willow and
across the MAT Valley. There is the potential that cloud cover
could limit thunderstorms if this happens showers are still
expected across much of the area, however current thinking is that
skies will clear enough by early afternoon and allow
thunderstorms to form. Showers should linger into Tuesday morning
as the shortwaves move south. Tuesday the ridge will move overhead
with lingering clouds clearing a bit in the afternoon also
temperatures should remain in the 60s to low 70s in most areas. An
isolated shower or thunderstorm is possible across the Wrangell
Mountains on Tuesday afternoon otherwise most areas will remain
dry Tuesday afternoon. Farther south a low pressure system south
of Kodiak Island will bring rain to the Island by Tuesday
afternoon tapering off Wednesday as the low move to the east. By
Wednesday the ridge will give way to a shortwave trough moving out
of western Alaska this will bring rain to the Susitna Valley by
Wednesday afternoon with rain chances increasing across the
Talkeetnas, the MAT valley and northern Copper River Basin by
Wednesday evening. Anchorage may even see a shot of rain by
Wednesday night.

&&

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

Remnants of overnight convection is headed south of Bristol Bay
this morning. Meanwhile, a ridge is passing through from north to
south as high clouds are filtering into the Kuskokwim Delta. Areas
of fog are confined to southern Bristol Bay and the AKPen this
morning and should begin to lift later this morning. As the Bering
low approaches the Pribilofs today, the pressure gradient along
the Southwest coast tightens, especially into Bristol Bay and will
lead to windier onshore flow. Isolated thunderstorms are possible
today for the interior Bristol Bay and along the Western Alaska
Range. Southeasterly flow at 850 could mix warmer air to the
surface towards New Stuyahok and Iliamna. Temperatures drop about
ten degrees closer to coast where onshore flow is strong and any
low stratus in the morning will slow temperatures from warming.

By Tuesday morning, the Bering low will move into the eastern
Bering and continue to move towards the AKPen. Rain showers
chances increase along the front and south of the Kuskokwim
mountains in the wrap around moisture. Isolated thunderstorms
inland cannot be ruled out Tuesday as a polar trough follows
closely behind the passage of the Bering low. The trough is
expected to pass from north to south beginning Tuesday night.
Temperatures will be trend cooler through the rest of the week.

&&

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

Bering Sea low is continuing southeast. Rainfall is being
reported in the Pribilofs this morning and chances will gradually
taper off this afternoon through tonight. A ridge is starting to
push out of the Eastern Aleutians as an upper jet streak develops
along the eastern Aleutians tonight. Chances for precipitation
will move along the Aleutians and pass through the AKPen
overnight. Chances for rain showers may linger on Tuesday that
form on the backside of the low. Flow will become northerly across
most of the Bering Sea and gusty winds may move through bays and
passes Wednesday morning, especially for the eastern half of the
Bering.

A high pressure ridge will bring weaker winds and quieter weather
going into midweek. A North Pacific low approaches the Western
Aleutians on Tuesday night, but the extent northward and will be
slow through Wednesday. Winds and precipitation chances could
begin increasing Wednesday night and reach as far east as Adak.

&&
.MARINE (Days 3 through 5: Wednesday through Friday)...

Gulf of Alaska: A front extending from a North Pacific low
lingers across the Gulf through Friday. A low forms over Kodiak
Island late Thursday. Forecast confidence is unsettled. Generally
light winds and seas less than 10 feet.

Aleutians/Bering: High pressure moves across the Bering through
Friday. A low approaches the Western Aleutians for Friday.
Forecast confidence is good. Gusty Westerly winds across the
Northern Bering, diminish late Thursday. Seas less than 10 feet.

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

Looking ahead into the long term forecast, models advertise a
similar synoptic pattern for the week. On Thursday, an upper-level
low is located over the Gulf of Alaska while another upper low is
positioned over the North Pacific near the Western Aleutians. A
shortwave ridge builds in between the two lows and extends from
the Central Aleutians east to the Alaska Peninsula. The Gulf low
gradually tracks east to the Panhandle through Sunday. The North
Pacific low moves over the Central Aleutians by Saturday morning
and then tracks east along the rest of the Chain and Alaska
Peninsula, reaching southwest Alaska late on Sunday. At the same
time, the aforementioned ridge builds to the east and spreads
across the Gulf by Sunday. For Saturday and Sunday, both
deterministic and ensemble models generally illustrate a low
breaking off from the main North Pacific low and moving either
along or south of the Western Aleutians. The main forecast
uncertainty at this time lies with the evolution and progression
of the North Pacific low and its secondary low, as well as the
development of various shortwaves within the flow. The latest GFS
runs show a secondary low developing south of the Aleutians by
Saturday night/Sunday morning, and this low remains south of the
Aleutians while its parent low tracks over the Alaska Peninsula.
The GEFS and Canadian mean hint at a similar type of synoptic
development and evolution. However, the GEM develops the secondary
low over the Aleutians late on Sunday as its parent low takes a
slightly more northern track over the interior part of Southwest.
The ECMWF is a bit of a mixed bag since it also brings the parent
low over interior Southwest but keeps its secondary low south of
the Aleutians. Thus, given the synoptic uncertainty for Saturday
and Sunday, forecast confidence decreases going into the weekend.
.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...KM
SOUTHCENTRAL ALASKA...RC
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...VR
MARINE/LONG TERM...KZ/AF

SPECIAL WEATHER STATEMENT
National Weather Service ANCHORAGE AK
911 AM AKDT Mon Jul 11 2022

AKZ141-112115-
Copper River Basin-
Including the cities of Glennallen, Eureka, McCarthy, Paxson,
and Slana
911 AM AKDT Mon Jul 11 2022

...STRONG THUNDERSTORM PRODUCING FREQUENT LIGHTNING NEAR THE
TANGLE LAKE RECREATION AREA AND EASTERN DENALI HIGHWAY THIS
MORNING...

A strong thunderstorm producing frequent lightning and possibly
small hail is moving over the Alaska Range towards the Tangle Lake
Recreation Area and the eastern Denali Highway. Anyone recreating
or outdoors in the area should seek shelter and avoid bodies of
water. The storms should move out of the area by 12 AKDT.