Storm Warning 7, NWS Juneau, AK

080 
FZAK67 PAJK 241329
OFFAJK

Offshore Waters Forecast
National Weather Service Juneau AK
429 AM AKST Sat Feb 24 2018

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.

PKZ398-250730-
429 AM AKST Sat Feb 24 2018
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A storm force low will move E through the northern Gulf Saturday.
This low will then track SE across the southern panhandle 
Saturday night, reaching western British Columbia by mid-Sunday 
morning. 

$$

PKZ310-250730-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
429 AM AKST Sat Feb 24 2018

...STORM WARNING TODAY THROUGH TONIGHT...

.TODAY...S wind 25 kt becoming W 40 kt in the morning, then
increasing to 50 kt in the afternoon. Seas 15 ft building to
21 ft in the afternoon. Rain early in the morning, then rain 
showers in the afternoon. 
.TONIGHT...W wind 45 kt. Seas 24 ft. Rain showers in the evening.
.SUN...NW gale to 35 kt. Seas 20 ft. 
.SUN NIGHT...SW wind 30 kt. Seas 15 ft. 
.MON...W gale to 40 kt. Seas 21 ft. 
.TUE...NW gale to 40 kt. Seas 22 ft. 
.WED...N wind 30 kt. Seas 16 ft. 

$$

316 
FZAK67 PAJK 250024
OFFAJK

Offshore Waters Forecast
National Weather Service Juneau AK
324 PM AKST Sat Feb 24 2018

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.

PKZ398-251830-
324 PM AKST Sat Feb 24 2018
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A storm force low in the eastern gulf will make landfall S of
Cape Edgecumbe Sat evening. This low will then track SE across 
the southern panhandle Saturday night. A new gale force low will 
track E across the northern gulf toward Yakutat late Sun night. 

$$

PKZ310-251830-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
324 PM AKST Sat Feb 24 2018

...STORM WARNING THROUGH TONIGHT...

.TONIGHT...W wind 50 kt becoming NW 40 kt late. Seas 24 ft. Snow
showers and rain showers. 
.SUN...NW wind 35 kt. Seas 20 ft. 
.SUN NIGHT...SW wind 25 kt. Seas 15 ft. W swell. Rain and snow
late. 
.MON...W gale to 40 kt. Seas 18 ft. Showers.
.MON NIGHT...W gale to 40 kt. Seas 23 ft. Showers in the
evening. Snow showers. Showers late. 
.TUE...NW gale to 40 kt. Seas 22 ft. 
.WED...N wind 30 kt. Seas 16 ft. 
.THU...N wind 30 kt. Seas 14 ft. 

$$

293 
FZAK67 PAJK 251353
OFFAJK

Offshore Waters Forecast
National Weather Service Juneau AK
453 AM AKST Sun Feb 25 2018

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.

PKZ398-260800-
453 AM AKST Sun Feb 25 2018
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A weakening low over the Southern panhandle will continue to
dissipate as it drifts into the Canada. A new storm  force low
will track E across the northern gulf to be just south  of
Yakutat by Monday morning.  

$$

PKZ310-260800-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
453 AM AKST Sun Feb 25 2018

...GALE WARNING EARLY TODAY THROUGH TODAY...

.TODAY...NW wind 40 kt diminishing to 30 kt in the afternoon.
Seas 20 ft. Rain and snow showers early in the morning. 
.TONIGHT...SW wind 25 kt. Seas 14 ft. W swell. Rain and snow
late. 
.MON...W gale to 40 kt. Seas 18 ft. Rain showers. 
.MON NIGHT...W gale to 45 kt. Seas 23 ft. Showers.
.TUE...NW gale to 45 kt. Seas 20 ft. 
.WED...N gale to 35 kt. Seas 14 ft. 
.THU...N wind 30 kt. Seas 12 ft. 

$$

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
251 PM AKST Fri Feb 23 2018

.SHORT TERM.../Through Saturday night/ A weakening low will move
SE out of the southern panhandle tonight. High pressure will build
over the Yukon tonight, then shift E Sat. A developing low will
move E into the NW gulf late tonight, then move across the
northern gulf Sat. The low should turn SE and move into the
southern panhandle Sat night. The associated occluded front will
move to the eastern gulf by early Sat morning, then swing across
SE AK Sat afternoon and evening. Generally preferred the 12z
GFS/Canadian handling of the second low, with the 12z NAM just a
little further N with the track. The 18z NAM shifted the low track
slightly southward and is very close to preferred consensus.

Main forecast concerns will be precip potential/ptype/amounts and
winds. Rain and snow showers with the low currently over the
southern area will move out tonight. Not expecting much in the way
of snowfall from these showers as low level temps will be above
freezing during most of this precip. Precip associated with the
second low and occluded front will move rapidly E across the gulf
and reach the outer coast of SE AK by around 15z Sat. This precip
should reach the far eastern inner channels by 20z Sat. Some
colder air will be in place ahead of the system, which will cause
precip to begin as snow pretty much all areas. Think the
central/southern coast and southern inner channels will transition
to rain or a mix, except for the far eastern parts, which should
remain mainly snow. Think the highest precip amounts will occur
from the central coast SE to the southern inner channels. The NE
part of this heavier precip band will likely remain mostly snow,
and have issued a winter weather advisory for zones 21,22, and 24
from 15z Sat to 01z Sun, and zone 26 from 18z Sat to 03z Sun.
Expect 3-5 inches in the advisory areas. Zones 20 and 25 could
get close to advy levels but some easterly flow will tend to limit
the snowfall a bit. Went for 2-4 inches for those areas Sat.
Lighter snowfall is expected over the far N. Hyder area will
likely see 3-5 inches of snow with the main frontal band Sat
afternoon and evening, but this is below advy levels. Elsewhere
along the coast and southern areas, 1 to 3 inches of snow will be
possible before it mixes with or changes to rain.

Precip should transition to showers Sat evening after occluded
front moves in. Most enhanced showers will be over the southern
half of the area along and S of the low track. The low itself will
have some mild air with it so most of the showers will likely be
rain along the southern coast. Precip over the N will diminish as
low moves inland Sat night.

Will have strong northerly winds over the northern inner channels
tonight between first low moving out and high pressure building
over the Yukon. Looking like gales for Lynn Canal with SCA level
winds possible over the central areas. These winds will decrease
rapidly late tonight and Sat morning as northerly gradient
weakens. Gale force W-NW winds will be over much of the S half of
the gulf to start tonight, then drop off gradually as flow backs
around to a more southerly direction late tonight ahead of
approaching occluded front, but after the front moves through, a
band of gale to storm force W-NW winds will move into the southern
half of the gulf Sat. Could be a small area of storm force winds
on S side of the low moving through the area as second wrap of
occluded front forms Sat. With the long fetch gale to storm force
winds over the central and southern gulf, seas will be very high,
with 20+ ft seas expected during much of the time through Sat
night.

Otherwise, some patchy fog will develop over parts of the central
and southern areas as clouds break and winds drop off this evening.
Think this fog will dissipate late tonight though as clouds
increase again ahead of the occluded front.

.LONG TERM.../Sunday through Friday/ We'll start off the long
term on Sunday with a broad upper level trough positioned over the
panhandle and western Canada and an upper level ridge building
over the western gulf. A weakening surface low associated with a
shortwave embedded within the upper level trough will continue to
traverse southeast across the panhandle, taking with it lingering
precipitation. This feature will also help to tighten the pressure
gradient between it and a weak high pressure near the border with
mainland Alaska and the Yukon. This setup may provide a brief
northerly outflow event, so we increased winds accordingly through
Lynn Canal. As the ridge of high pressure strengthens over the
gulf and pushes east Sunday night into early Monday morning, this
should help to fully clear out precipitation, albeit briefly,
before our next system moves in Monday.

Continuing with our progressive pattern trend, a shortwave with
an associated developing surface low will dig into the western
gulf Sunday night. A weather front with the low will lift across
the eastern gulf and impact the panhandle Monday continuing into
Tuesday. 700 mb model frontogenesis shows strengthening along the
front, which should help trigger the lift we need for
precipitation. Models also show significant moisture advection
ahead of the front on Monday, so we could see some substantial
precip amounts with this system. This may potentially be a tricky
system regarding precip type; model 925 mb temps show a relatively
cold air mass over the panhandle, so precip could start off as
snow and briefly transition to a rain/snow mix or remain all snow.

We mainly focused on forecast updates for the early period in the
long term, which included the Sunday through Monday timeframe. We
chose a NAM/GEM blend, using NAM more for winds and GEM for
precip elements. After this timeframe, we allowed WPC guidance to
remain and added in NBM for select elements, mainly temperatures,
which were adjusted down for later next week.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Winter Weather Advisory from 9 AM to 6 PM AKST Saturday for
     AKZ026.
     Winter Weather Advisory from 6 AM to 4 PM AKST Saturday for
     AKZ021-022-024.
MARINE...Gale Warning for PKZ012-041>043-051-052.
     Small Craft Advisory for PKZ013-021-022-031>036.
     Small Craft Advisory due to Seas for PKZ053.

&&

RWT/Voveris

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

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE JUNEAU AK
1025 AM AKST FRI FEB 23 2018

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

0600 AM     SNOW             PETERSBURG              56.81N 132.96W
02/23/2018  M1.8 INCH                           AK   OTHER FEDERAL

            STORM TOTAL AT PETERSBURG AIRPORT. CURRENTLY RAINING.

0600 AM     SNOW             8 S PETERSBURG          56.70N 132.96W
02/23/2018  M5.1 INCH                           AK   TRAINED SPOTTER

            STORM TOTAL SNOWFALL AT 9 MILE MITKOF HIGHWAY.

0600 AM     SNOW             EAGLECREST              58.27N 134.51W
02/23/2018  M6.0 INCH                           AK   CO-OP OBSERVER

            AT THE BASE OF EAGLECREST SKI AREA.

0700 AM     SNOW             34 WNW HAINES           59.43N 136.33W
02/23/2018  M4.0 INCH                           AK   CO-OP OBSERVER

            24 HOUR SNOWFALL AT HAINES CUSTOM STATION.

0700 AM     SNOW             EAGLECREST              58.27N 134.51W
02/23/2018  M7.0 INCH                           AK   CO-OP OBSERVER

            MEASURED AT THE TOP OF EAGLECREST SKI AREA.

0800 AM     HEAVY SNOW       YAKUTAT                 59.54N 139.73W
02/23/2018  M7.0 INCH                           AK   OFFICIAL NWS OBS

            STORM TOTAL AT YAKUTAT AIRPORT.

0815 AM     SNOW             HYDER                   55.91N 130.02W
02/23/2018  M6.2 INCH                           AK   CO-OP OBSERVER

            24 HOUR SNOWFALL AT HYDER

0825 AM     SNOW             8 N SKAGWAY             59.59N 135.33W
02/23/2018  M3.0 INCH                           AK   DEPT OF HIGHWAYS

            24 HOUR SNOW AMOUNT AT SKAGWAY CUSTOMS STATION.

0825 AM     SNOW             14 N SKAGWAY            59.68N 135.33W
02/23/2018  M5.0 INCH                           AK   DEPT OF HIGHWAYS

            24 HOUR SNOW ACCUMULATION AT WHITE PASS.

0900 AM     SNOW             1 S MENDENHALL GLACIER  58.40N 134.55W
02/23/2018  M2.1 INCH                           AK   OFFICIAL NWS OBS

            STORM TOTAL AS OF 9 AM FRIDAY AT THE JUNEAU FORECAST
            OFFICE.

1015 AM     SNOW             10 S WRANGELL           56.33N 132.40W
02/23/2018  E2.4 INCH                           AK   TRAINED SPOTTER

            ALL OF THE SNOWFALL HAPPENED BEFORE 10 PM LAST NIGHT.
            RAIN AFTER THAT. AT 11 MILE ZIMOVIA HIGHWAY.

&&

EAL