Storm Warning 24, NWS Juneau, AK

159 
FZAK67 PAJK 091122
OFFAJK

Offshore Waters Forecast
National Weather Service Juneau AK
322 AM AKDT Sun Aug 9 2020

Offshore waters forecast for Gulf of Alaska east of 144W

Wind forecasts reflect the predominant speed and direction
expected. Sea forecasts represent the average of the highest
one-third of the combined windwave and swell height.

PKZ398-100530-
322 AM AKDT Sun Aug 9 2020
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A storm force low in the central gulf will track NE to near 
Yakutat before dissipating through Monday morning. The associated 
front will move through the panhandle Sunday. Behind the front, 
strong SW flow will persist into Monday 

$$

PKZ310-100530-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
322 AM AKDT Sun Aug 9 2020

...STORM WARNING TODAY...

.TODAY...S wind 35 kt becoming W 50 kt. Seas 18 ft. Rain early in
the morning. 
.TONIGHT...W wind 35 kt diminishing late. Seas 18 ft. 
.MON...W wind 25 kt. Seas 12 ft. W swell. 
.MON NIGHT...W wind 20 kt. Seas 10 ft. W swell. 
.TUE...W wind 15 kt. Seas 7 ft. 
.WED...Wind variable less than 15 kt. Seas 6 ft or less. 
.THU...S wind 15 kt. Seas 6 ft or less. 

$$

819 
FZAK67 PAJK 100028 AAA
OFFAJK

Offshore Waters Forecast
National Weather Service Juneau AK
321 PM AKDT Sun Aug 9 2020

Offshore waters forecast for Gulf of Alaska east of 144W

Wind forecasts reflect the predominant speed and direction
expected. Sea forecasts represent the average of the highest
one-third of the combined windwave and swell height.

PKZ398-101730-
321 PM AKDT Sun Aug 9 2020
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A gale force low in the northern gulf will track NE onshore just 
E of Yakutat before dissipating through Monday morning. An 
associated front will move through the panhandle Sunday night into 
Monday. 

$$

PKZ310-101730-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
321 PM AKDT Sun Aug 9 2020

...GALE WARNING THROUGH TONIGHT...

.TONIGHT...W wind 45 kt diminishing to 30 kt late. Seas 23 ft 
subsiding to 16 ft late. 
.MON...W wind 25 kt. Seas 12 ft. W swell. 
.MON NIGHT...W wind 20 kt. Seas 9 ft. W swell. 
.TUE...W wind 15 kt. Seas 7 ft. W swell. 
.TUE NIGHT...Wind variable less than 15 kt. Seas 6 ft or
less. W swell. 
.WED...Wind variable less than 15 kt. Seas 6 ft or less. 
.THU...S wind 15 kt. Seas 6 ft or less. 
.FRI...SW wind 15 kt. Seas 6 ft or less. 

$$

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
327 PM AKDT Sat Aug 8 2020

.SHORT TERM...As a vigorous storm pulls out of the SW gulf, a
responding ridge has popped up across Southeast Alaska ensuring
breezy conditions across the Panhandle today. Showers, too, have
been heavy at times across the region as a vorticity max rides
northeastward.

The track as noted previously has driven the low along a farther
south path. And therefore, the threat of high winds to Yakutat
has ended. We will cancel the high wind watch and replace it with
strong winds for Monday morning. Storm force winds, though
curtailed in duration with the southeast barrier jet near Cape
Fairweather, will still appear in the open gulf resulting from the
sting jet to the low's south. Windy conditions for the northern
Panhandle look good. Due to parallel gradient, we did diminish
winds in Lynn Canal late tonight into Sunday morning to lend a
small break. Also, we turned wind directions in Icy Strait from
southeast to westerly from late Sunday afternoon into much of
Sunday night. In addition we expanded periods for strong winds
into Monday morning for Skagway and Haines as well.

Integrated vapor transport (IVT) of 500 to 700 kg/m/s and high
probabilities of exceeding 10-year return intervals for several
locations in the north have prompted coordination with RFC to
raise many streams to bankfull conditions Sunday night for the
northern Panhandle. Basically we have 2 to 4 inches of rainfall
from Yakutat to Juneau and down to Sitka with lighter amounts of 1
to 2 inches from Upper Lynn Canal to Hoonah. CIRA layered PW
indicates a deep swath of moisture over the SW gulf directed by
this system as well. Impressive heavy rain rates of 0.30/hour are
indicated on MIRS satellite rain rate images. Once the system
reaches our terrain, embedded showers could produce this much or
more at times.

Moving forward, strong onshore flow and continued bands of
vorticity continues to support showers across the Panhandle
Monday, even as southerly winds slowly diminish. The Marine
Weather Statement will expire at 4PM as its outlook function has
served well. The Special Weather Statement was given more details.

.LONG TERM.../Mon through Sat as of 10 pm Fri/Latest model
guidance is giving indications that next week may not be as
interesting as thought compared to previous long range forecasts.
As we begin the work week Monday, the strong storm system
impacting the region will be winding down. Gale force winds will
still be occurring in some parts of the Gulf and Northern Lynn
Canal at the onset of the forecast period, with a smattering of
SCA winds through the inner channels and coastal areas. Currently
expecting the pressure gradient to loosen up over the course of
the day which will decrease the wind threat significantly by
Monday night. Rain showers behind the main system will still be
moving through the panhandle, however rainfall rates and overall
coverage will be greatly reduced from the previous 24 hours.

Ridging begins to build in over the region Monday night. While
onshore flow will continue to keep some PoP chances for the
panhandle, these numbers will be greatly reduced. The forecast
begins to differ quite a bit at this point from previous
iterations. Tuesday night, surface flow begins to swing to the NW
and remains as such through Thursday. Such a situation could
potentially lead to multiple consecutive dry days for some
locations. However, given the subtle discrepancies within the
current model suite, and the fact that this change is fairly new,
have retained PoPs in the 20s and 30s and will certainly re-
evaluate when creating tomorrow's forecast package. Regardless of
anything, will continue to forecast for mostly cloudy conditions
through the week, however if it does look like this pattern will
hold up for future forecasts, may be able to slash some of the
dreariness from the sky forecast.

Vast discrepancies between models exist with a potential late
week storm system. While we will not speculate on specific potential
impacts quite yet, the timing and track is worthy of note. The
wide canyon between the GFS and ECMWF solutions is of particular
interest. GFS will have this system bring a front through the
southern and central panhandle Friday into Friday night. The EC
on the other hand delays this system to nearly the end of the
forecast period Saturday night and further, mostly passing south
of the region. Will definitely require further guidance before
attempting to nail down what, if anything, this system will do.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind from late tonight through Sunday morning for AKZ024.
     Strong Wind from Sunday morning through late Sunday night for
     AKZ020-025.
     Strong Wind from Sunday afternoon through late Sunday night for
     AKZ022.
     Strong Wind from late tonight through late Sunday night for
     AKZ023.
     Strong Wind from Sunday afternoon through late Sunday night for
     AKZ019.
     Strong Wind from Sunday evening through late Sunday night for
     AKZ018.
     Strong Wind Sunday morning for AKZ017.
MARINE...Storm Warning for PKZ051.
     Gale Warning for PKZ022-031-041>043-052.
     Small Craft Advisory for PKZ011>013-021-032>036-053.

&&

JWA/JDR

Visit us at http://www.weather.gov/Juneau

Special Weather Statement
National Weather Service Juneau AK
147 PM AKDT Sat Aug 8 2020

AKZ017>025-091000-
Cape Fairweather to Cape Suckling Coastal Area-
Taiya Inlet and Klondike Highway-Haines Borough and Lynn Canal-
Glacier Bay-Eastern Chichagof Island-
Salisbury Sound to Cape Fairweather Coastal Area-
Cape Decision to Salisbury Sound Coastal Area-
Eastern Baranof Island and Southern Admiralty Island-
Juneau Borough and Northern Admiralty Island-
Including the cities of Yakutat, Skagway, Haines, Gustavus,
Hoonah, Elfin Cove, Pelican, Sitka, Port Alexander, Angoon,
and Juneau
147 PM AKDT Sat Aug 8 2020

...GUSTY AND VERY WET LATE SATURDAY NIGHT INTO MONDAY MORNING...

A storm will bring strong winds and very wet weather Saturday
night into Monday morning. Wind gusts up to 50 mph are expected,
first along the coast Sunday morning and then spreading inland
through Sunday night.

Rain is also expected to become heavy, first along the coast early
Sunday morning and then spreading inland through early Monday
morning. Rainfall totals of 2 to 4 inches are expected in Juneau,
Sitka, Gustavus, Yakutat, Tenakee Springs, Elfin Cove, and
Pelican. For Haines, Skagway, and Hoonah, 1 to 2 inches are
expected. Rain totals between Cape Fairweather and Cape Spencer
could result in 3 to 6 inches of rainfall. Given already saturated
conditions from a wet summer, some area streams and rivers are
expected to reach bankfull conditions Sunday night. However,
flooding is not expected at this time.