Gale Warning 507, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion...CORRECTED
National Weather Service Anchorage AK
843 AM AKDT Wed Oct 23 2019

.ANALYSIS AND UPPER LEVELS...
A strong 960 mb surface low is currently crossing the Alaska
Peninsula near Port Heiden early this morning. The associated
frontal system is currently lifting north across Southwest Alaska,
the Kenai Peninsula and the northern Gulf. The frontal system has
been producing storm force east to northeast winds out ahead of
the front with storm force west to northwest winds pushing in
with the wrap around portion of the front west and south of the
low center.

Additionally, strong gap winds have been channeling through
favorably oriented terrain...particularly easterly gap winds along
the west slopes of the Alaska and Aleutian Ranges in Southwest
Alaska. Northwest winds are blasting through the gaps and passes
in the eastern Aleutians in the Alaska Peninsula, while southeast
winds push through Turnagain arm and other similarly oriented
gaps in Chugach and Kenai Mountains. Strong barrier jet easterlies
are setting up along the northern Gulf coast and pushing into
Prince William Sound.

For the most part this frontal system is warm enough to be
rain in the lower elevations of the area, with moderate to heavy
rain at times along the coast. With colder air in the Copper
River Basin, precipitation is initially falling as snow. Upslope,
northeasterly flow along the western side of the Copper River
Basin and south side up through Thompson pass is acting to
enhance snow fall there.

&&

.MODEL DISCUSSION...
Overall models remain in good agreement regarding the strong low
pressure system tracking through the area this morning. The timing
of the frontal system however has sped up by roughly 3 hours as
compared to previous runs and this faster timing is being
verified by both surface observations and satellite imagery.
Models are also in good agreement regarding the next strong low
tracking in from the west to the south of the Aleutians Thursday
and Friday.

&&

.AVIATION...
PANC...Strong easterly flow aloft will support continued VFR
conditions and with only occasional light rain expected at PANC.
Wind shear this morning due to the contrast between low level
northerly flow and strong east winds aloft will end around 18Z
as the frontal system lifts north of the area. At this point, gusty
south to southeasterly winds from Turnagain arm will push into
town.

&&

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

A strong low currently centered over Bristol Bay and its
associated front will bring unsettled weather across Southcentral
today. High Wind Warnings remain in effect for Portage Valley,
Turnagain Arm, and the upper hillside of Anchorage (above Hillside
Drive). Gusts up to 80 mph are possible through this morning as
the front lifts northward. Winds up to 65 mph are also possible
along the coast of Prince William Sound. These will quickly
diminish later this morning into the afternoon after the frontal
passage. However, winds in the Anchorage Bowl will consequently
shift to southeasterly and increase to near 25 mph during this
time period and will remain as such through Thursday morning.

Periods of heavy rain are likely over the southern and western
Kenai along with coastal areas along Prince William Sound. Seward
in particular may see more rain than previously forecasted as they
have already switched to southerly winds. Though rain has moved as
far north as the Sterling Highway, downsloping is still expected,
especially farther north into Anchorage where precipitation will
be limited until the main low and associated cross barrier flow
weaken.

Though much of the precipitation will remain as rain,
accumulating snow of 3-5" is likely across portions of the Glenn
Highway, mainly in the Eureka area. Amounts will diminish farther
east, however up to half an inch is possible as far as Glennallen.

Winds will diminish across Southcentral by Thursday afternoon as
the low becomes vertically stacked and weakens. Scattered showers
will overspread areas that were previously downsloped, with
steady rain continuing in Seward and coastal Prince William Sound
in persistent warm, southerly flow. Skies will finally clear by
Friday as high pressure builds over the southern gulf.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1-3: Wed through Fri)...

Widespread precipitation will continue across much of Southwest
Alaska today as a strong North Pacific low moves inland. Windy
conditions will persist across much of the region through this
evening. Sustained winds of 30+ mph with gusts up to 45 mph and
greater have already been observed around Bristol Bay this
morning, including King Salmon and Iliamna. Winds will shift to a
northerly direction and begin to weaken as the low's center moves
into inland Bristol Bay this evening into Thursday morning.

A Special Weather Statement (SPS) has been issued for possible
rough seas again the coast that could cause coastal erosion from
Port Moller to Egegik, including Port Heiden, starting this
afternoon through Thursday afternoon. Please see the SPS for more
details.

Temperatures should stay warm enough to keep new precipitation as
rain as the front continues to lift northward today. However,
colder air will move into the Kuskokwim Delta area by this evening,
leaving some uncertainty in timing of when rain will transition
over to snow. Snowfall accumulations will be confined to higher
elevations, but lower lying areas, including Bethel, could see
trace amounts of snow today. The precipitation begins to taper
off heading into Thursday evening giving the Southwest a brief
period of drying conditions before the front moves inland bringing
another round of widespread precipitation for Friday afternoon.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1-2: Wed through
Thur)...

Storm force sustained winds will move into coastal waters south
of the AKPEN, extending from King Cove to Kodiak Island, by this
afternoon as the North Pacific low continues to lift northward.
During this time, hurricane-force wind gusts are possible. Winds
will slightly weaken to gale-force by Thursday morning as the
low's center continues to push inland. Gale-force north to
northwest flow will continue over the eastern Bering this morning
through Thursday afternoon, when winds begin to weaken Thursday
night.

The next system enters the western Bering and Aleutians on
Thursday morning, with its front making it to the Pribilofs
overnight Thursday into the early Friday morning hours. This
strong low will bring another batch of storm-force winds to the
Bering along with widespread precipitation.

&&

.MARINE (Days 3 through 5)...
There is high confidence of a low near the central Aleutians
bringing storm force winds to the western Bering and Aleutians
Friday. There is also high confidence of the winds weakening
through the weekend as the low tracks north into the Bering. Over
the Gulf there is high confidence in westerly winds that will
change to southeasterly through the weekend. However, the models
are struggling with how strong the winds will be. Current thinking
is that normal gusty areas in westerly flow, like areas around
the Barrens, will see gale force winds Friday. Minor changes in
low position could play a factor in how strong these winds will
be.

&&

.LONG TERM FORECAST (Days 3 through 7)...
The long term, beginning Friday, has ridging building in over the
southern mainland and a storm force low just south of the central
Aleutians. As the ridging continues to strengthen it will force
the low to track north into the Bering over the weekend as the
low weakens. Between these two features an atmospheric river will
setup bringing a long fetch of moisture initially to the Alaska
Peninsula. There is disagreement amongst the models with the
progression of the atmospheric river, but the general consensus
has it tracking to the east into early next week. The models
diverge quite a lot early next week resulting in the ensembles
being preferred.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...High Wind Warning 101 125.
MARINE...Storm Warning 119 125 131 132 138 150 155 178.
		 Gale Warning 120 129 130 136 137 139 140 160 165 170-172
				      175-177 180-185.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...JER
SOUTHCENTRAL ALASKA...AP
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...AH
MARINE/LONG TERM...DK

SPECIAL WEATHER STATEMENT
National Weather Service ANCHORAGE AK
304 PM AKDT Wed Oct 23 2019

AKZ161-181-241300-
Bristol Bay-Alaska Peninsula-
Including the cities of King Salmon, Dillingham, Naknek,
Pilot Point, Cold Bay, and Sand Point
304 PM AKDT Wed Oct 23 2019

...COASTAL EROSION AND ROUGH SURF POSSIBLE FROM PORT MOLLER TO
EGEGIK WEDNESDAY AFTERNOON THROUGH THURSDAY EVENING...

Strong north to northwesterly winds will impact the coast from
Port Moller to Egegik, including Port Heiden, Wednesday afternoon
through Thursday evening. Sustained winds between 35 and 45 mph
are likely.

High seas against the coast could cause coastal erosion. Models
continue to indicate that the highest water levels coincide with
low tide. However, we will continue to monitor the path and the
timing of the storm in case this timing changes.

Make sure to prepare by securely tying property down or moving
items away from the immediate coast.

Stay updated with the current forecast at www.weather.gov/Anchorage.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
348 PM AKDT WED OCT 23 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0456 AM     NON-TSTM WND GST 1 NE PORTAGE            60.79N 148.83W
10/23/2019  E81 MPH                             AK   ASOS

            81MPH WIND GUST OCCURRED AT 0456AM AKDT.

&&

EDREWITZ