Areal Flood Warning 5, NWS Anchorage, AK

904 
WGAK88 PAFC 010030
FLSAFC

Flood Statement
National Weather Service Anchorage AK
430 PM AKDT Sun Oct 31 2021

AKZ125-011845-
/O.CON.PAFC.FA.W.0005.000000T0000Z-211101T1845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Western Prince William Sound AK-
430 PM AKDT Sun Oct 31 2021

...FLOOD WARNING REMAINS IN EFFECT UNTIL 1045 AM AKDT MONDAY FOR 
STREAMS IN THE GIRDWOOD AREA...

At 430 PM AKDT, As of 3:00 PM on Sunday, Girdwood has received a 
running storm total precipitation of over 10 inches. Precipitation 
will start to taper off as the focus shifts eastward, although 
another 1.5 to 2.5 inches in town is likely through Monday morning.




  Small streams and creeks in residential areas will continue to see 
  minor flooding. Glacier Creek is expected to remain at bankfull, 
  but below flood level. Area roads will continue to see minor 
  flooding. There have been reports of full and damaged culverts.

Please stay tuned to weather.gov/Anchorage, NOAA weather radio or 
your favorite local weather news source for updates on this 
situation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 6094 14918 6096 14914 6097 14913 6099 14909
      6099 14908 6095 14913 6093 14917 6094 14917

$$

Zingone

579 
WGAK88 PAFC 011831
FLSAFC

Flood Statement
National Weather Service Anchorage AK
1031 AM AKDT Mon Nov 1 2021

AKZ125-011841-
/O.CAN.PAFC.FA.W.0005.000000T0000Z-211101T1845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Western Prince William Sound AK-
1031 AM AKDT Mon Nov 1 2021

...FLOOD WARNING IS CANCELLED FOR WESTERN PRINCE WILLIAM SOUND 
ZONE...

Flooding is no longer expected to pose a threat. Water levels will 
remain elevated, but are expected to slowly fall. Please continue to 
heed remaining road closures.

LAT...LON 6094 14918 6096 14914 6097 14913 6099 14909
      6099 14908 6095 14913 6093 14917 6094 14917

$$

Shea

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
528 PM AKDT Sat Oct 30 2021

.ANALYSIS AND UPPER LEVELS...

A major storm system is moving into southern mainland Alaska this
afternoon. The center of the low causing this active weather is
near Sitkinak Island southwest of the southern tip of Kodiak
Island. Much of Southcentral is in the warm eastern half of the
low. As such, strong southerly flow is bringing moisture from the
tropics and directing it in a narrow 100 mile wide band (called an
atmospheric river) into the Kenai Peninsula and Prince William
Sound. This has been the reason there have been such large amounts
of rain so far, with Portage closing in on 6 inches of rain and
Seward nearing 3 inches for the storm. The rain is far from over,
even as the heaviest rain shifts east into Prince William Sound.
On the wind side of this storm, gusts have reached as high as 89
mph in Portage, 45 mph along the Hillside and in Palmer, 47 mph in
Seward, and 53 mph in Gulkana.

Over Southwest Alaska, there has been a very well-defined front
located between New Stuyahok and Igiugig. East of this front,
temperatures have risen into the 40s with occasional light rain.
West of the front, snow has been ongoing in Koliganek, Dillingham,
Sleetmute, and has begun in Aniak and Kalskag. Thus far, very
little freezing rain has been reported across Southwest Alaska.
It's been either rain or snow in almost all areas.

In the upper levels, a deep and highly amplified trough dips south
to near 30N. Ahead of this trough, a 120 kt southerly jet is
transporting ample moisture into Southcentral, causing the rain
that's ongoing along the north Gulf Coast. Ridging is in place
ahead of the trough, whose axis is over the Yukon. A straight
northwesterly jet is over the Bering.

&&

.MODEL DISCUSSION...

The models are in good agreement on the large-scale weather
pattern. The primary area of uncertainty continues to be total
rainfall and when the highest wind gusts will occur. The rainfall
totals in Seward are particularly difficult as the main
atmospheric river shifts away from them, but upslope continues to
produce rain, though not has heavy as occurred last night into
this morning. Where the rain-snow line sets up over Southwest
Alaska and how far west the snowfall gets this evening are also
points of uncertainty. Overall forecast confidence is average, but
the finer details of the forecast remain below average.

&&

.AVIATION...
PANC...VFR to MVFR conditions are expected through this afternoon
as much of the rainfall trying to make it over the mountains
evaporates before it reaches the ground into this evening. Wind
shear will persist through the overnight hours as strong
southeasterly flow continues aloft. The wind shear will diminish a
bit as the winds at the surface flip to southeasterly as well late
this afternoon, however the shear at that point will be in the
form of speed shear.

Rain is expected to begin and will be more consistent going into
the overnight hours as the core of the strongest moisture
advection moves overhead. It will only ever be light in intensity,
and the persistent strong winds aloft should hold ceilings to MVFR
at worst, and visibilities will remain VFR. Conditions will
improve a bit Sunday morning.

&&

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

Steady light to moderate rain and strong gusts were reported
across the Gulf and Southcentral since this morning, and this
pattern will continue into this evening until winds and rainfall
begin to taper off late tonight into Sunday morning. Gusts of 70
to 100 mph were observed mainly along Turnagain Arm and higher
elevations over the eastern Turnagain Arm and Portage area this
afternoon. A stacked low passing through Shelikof Strait is
directing a lot of tropical moisture, rain and much stronger winds
across the Gulf and the southern portion of Southcentral this
evening. Warm southeasterlies associated with the frontal system
over the Gulf will maintain intermittent rainfall in the forecast
for the next couple days.

A developing upper trough over the eastern Bering will bring
another round of mixed rain/snow Sunday evening into Monday
afternoon. Along the west side of this trough, cold air advection
with temperatures of -6 to -11 degrees Celsius at 850 mb could
likely make it across Southcentral by Mon morning, otherwise this
pocket of colder air may get held up over the Alaska Range instead.
The potential for snow is favorable north of Matanuska Valley
with light to moderate rain expected across the coastal areas from
Kodiak Island through Kenai Peninsula through Prince William Sound
and farther inland on Mon and Tue.

Essentially, an active weather pattern will continue into early
next week, with winds and rain slowing down a bit on Mon and Tue
in comparison to the existing event producing high wind warning
near Anchorage and western Prince William Sound through late
tonight, and Flood Warning for Seward and a Flood Advisory for
Anchor River near Anchor Point until Sunday morning.

&&

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

An active weather pattern will quiet down over the next day across
Southwest Alaska as a storm system currently over the area moves
away to the east. Temperatures remain cold enough to support snow
in the Kuskokwim Delta, western lower Kuskokwim Valley and Bristol
Bay going from Dillingham north and west. Temperatures will fall
over the next several hours over the entirety of Southwest Alaska
as strong cold air advection moves in behind the low. This will
allow for areas experiencing rain or a wintry mix to change to all
snow this evening and tonight. Temperatures will remain warm
enough this evening across the northern Alaska Peninsula for rain
to continue. Precipitation will taper off across the eastern
Kuskokwim Delta, western lower Kuskokwim Valley, and Bristol Bay
Sunday morning. Precipitation will continue across the eastern
lower Kuskokwim Valley through Monday morning.

The pattern then becomes quiet and cold for Monday and Tuesday
across Southwest Alaska. This will allow for snow showers along
the Kuskokwim Delta coast as strong cold air advection is expected
over the water which will support the formation of convective
snowbands. This pattern will continue through Tuesday.

&&

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

A fairly quiet but unsettled pattern is expected across the
Bering/Aleutians over the next couple of days. Widespread gale
force northerly winds in the eastern Bering/Aleutians and in
Bristol Bay will gradually ease over the next 24 hours. The next
low will enter the western Bering Sea Sunday evening and move
northeastward into the north central Bering Sea by Tuesday. Areas
of gale force winds are expected with this low in addition to
convective snow showers on the west side of the low.

&&

.MARINE (Days 3 through 5 - Tuesday through Thursday)...

Aleutians/Bering... A low complex and front sweep into the
Eastern Bering for Thursday. Gusty winds across the Bering with
areas of gales over the Northern Bering, diminishing. Seas to 20
feet over the Central Bering, subsiding Wednesday. Forecast trend
becomes unsettled by Thursday. A Northern Bering low moves South
by Thursday, bringing Westerly gales from the Western Bering
Wednesday into the Central Aleutians by Thursday. Seas building to
28 feet over the Southern Bering for Thursday.

Gulf of Alaska... A well-developed North Pacific low moves over
the Western Gulf and inland for Wednesday. Southeasterly gales
with its front continue over the Gulf, diminishing Wednesday.
Gusty Northwesterly winds on the Western flank diminish late
Tuesday. Seas to 22 feet will subside Wednesday. A second North
Pacific low moves to the Central North Gulf Coast, then dissipates
Thursday.

&&

.LONG TERM FORECAST (Days 3 through 7: Tuesday through Saturday)...

A series of weak to moderate-strength lows moving northwestward
across the Gulf will keep conditions unsettled across the entire
north Gulf Coast Tuesday, with some indication that some of that
moisture will make it over the mountains to impact areas such as
Anchorage, the Mat Valley, and the Copper River Basin. The same
pattern continues into Wednesday as the last of the lows move into
the coast. A separate front will begin impacting the coast of
Southwest Alaska either Tuesday or Wednesday, and is expected to
stall out along the coast, keeping conditions mild and unsettled
across the area. As a low tracks southward along the front
Thursday, it will gradually take much of the associated moisture
along with it. This will make for a dry day on Friday and
Saturday. For Southcentral, the low centered somewhere near Kodiak
on Friday will keep conditions unsettled until Saturday.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisories: 152, 155, 161.
         High Wind Warning: 101, 125.
         Flood Advisory: 121.
         Flood Warning: 125.
MARINE...Storms: 119, 125.
         Gales: 120, 128, 130, 131, 132, 136-138, 150, 155, 160,
                165, 178, 180, 351, 352, 411.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...JPW
SOUTHCENTRAL ALASKA...CB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...ED
MARINE/LONG TERM...KZ/JPW