Gale Warning 235, NWS Anchorage, AK

589 
FZAK61 PAFC 221139
OFFAER

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
339 AM AKDT TUE MAR 22 2016

OFFSHORE WATERS FORECAST FOR THE GULF OF ALASKA WEST OF 144W

WIND FORECASTS REFLECT THE PREDOMINANT SPEED AND DIRECTION
EXPECTED. SEA FORECASTS REPRESENT AN AVERAGE OF THE HIGHEST
ONE-THIRD OF THE COMBINED WIND WAVE AND SWELL HEIGHT.

PKZ399-230100-
339 AM AKDT TUE MAR 22 2016
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...
A TROUGH OF LOW PRESSURE MOVES FROM THE CENTRAL TO NORTHERN GULF
BY TUESDAY AFTERNOON BEFORE MOVING ONSHORE. A DEVELOPING NORTH
PACIFIC LOW MOVES TO 56N 139W AT 996 MB THU MORNING. TUE AFTERNOON
THEN TO 53N 140W AT 986 MB WED AFTERNOON. A WEAK LOW FORMS NEAR
56N 153W AT 1000 MB THU MORNING BEFORE DISSIPATING BY THU
AFTERNOON.

$$

PKZ351-230100-
GULF OF ALASKA OFFSHORE NORTH OF 57N AND WEST OF 144W-
339 AM AKDT TUE MAR 22 2016

...STORM WARNING TONIGHT...

.TODAY...SE WIND 20 TO 30 KT. SEAS 7 TO 10 FT.
.TONIGHT...E WIND 35 TO 50 KT. SEAS 10 TO 18 FT. RAIN.
.WED...E WIND 25 TO 40 KT DIMINISHING TO 15 TO 30 KT IN THE
AFTERNOON. SEAS 15 TO 18 FT. RAIN.
.WED NIGHT...E WIND 10 TO 20 KT. SEAS 9 TO 15 FT.
.THU...SE WIND UP TO 15 KT. SEAS 7 TO 10 FT.
.FRI THROUGH SAT...SE WIND 15 TO 30 KT. SEAS 9 TO 14 FT.

$$

PKZ352-230100-
GULF OF ALASKA OFFSHORE SOUTH OF 57N NORTH OF 55N AND WEST OF
144W-
339 AM AKDT TUE MAR 22 2016

...STORM WARNING TONIGHT...

.TODAY...SE WIND 10 TO 25 KT BECOMING E 25 TO 40 KT IN THE
AFTERNOON. SEAS 7 FT BUILDING TO 9 TO 14 FT IN THE AFTERNOON.
RAIN.
.TONIGHT...E WIND 35 TO 50 KT. SEAS 13 TO 17 FT. RAIN.
.WED...E WIND 10 TO 25 KT. SEAS 12 TO 17 FT. RAIN.
.WED NIGHT...NE WIND UP TO 15 KT. SEAS 9 TO 16 FT.
.THU THROUGH FRI...S WIND 15 TO 30 KT. SEAS 8 TO 13 FT.
.SAT...W WIND 10 TO 25 KT. SEAS 7 TO 12 FT.

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
542 AM AKDT MON MAR 21 2016

.ANALYSIS AND UPPER LEVELS...

THE MAIN FEATURE IN PLACE THIS MORNING IS A LARGE UPPER LOW THAT
IS SLOWLY PUSHING SOUTH OVER THE ALASKA PENINSULA. THE LOW IS DRIVING
AN AMPLIFIED UPPER LEVEL PATTERN WITH MOIST ONSHORE FLOW OVER
CENTRAL ALASKA AND COLD NORTHERLY FLOW OVER THE FAR WESTERN
MAINLAND AND THE BERING SEA. AT THE SURFACE A WEAKENING WARM
FRONT IS PUSHING SOUTHWESTWARD OVER THE SOUTHWEST COAST. UPPER-
LEVEL DISTURBANCES OVER THE SOUTHWESTERN MAINLAND ARE TAPPING INTO
THE MOISTURE STREAMING OVER THE ALEUTIAN RANGE BEHIND THE FRONT.
THIS IS BRINGING SNOW TO THE LEEWARD SIDE OF THE ALEUTIAN RANGE
WHERE COLD AIR HAS BEEN ENTRENCHED AT THE SURFACE FOR THE PAST FEW
DAYS. THIS COLD SURFACE AIR HOWEVER IS RAPIDLY ERODING TO WARM AIR
ADVECTION BEHIND THE WARM FRONT AND ADIABATIC WARMING AS THE AIR
DESCENDS TO THE EASTERN BRISTOL BAY REGION...MARKING AN END TO THE
RECENT SOUTHWEST ALASKA "COLD" SPELL (AT LEAST BY THIS WINTER'S
STANDARDS). ILIAMNA HAS UNDERGONE A 26 DEGREE FAHRENHEIT
TEMPERATURE RISE FROM THIS TIME YESTERDAY MORNING...WHILE ANIAK
AND KING SALMON HAVE INCREASED 15 DEGREES AND 13 DEGREES
FAHRENHEIT RESPECTIVELY IN THE LAST 24 HOURS. THE WARM PUSH IS
JUST STARTING TO MAKE ITS WAY NORTH TO THE KUSKOKWIM DELTA
REGION...WHERE COLD OFFSHORE SURFACE FLOW CONTINUES TO PREVAIL AND
HOLDS TEMPERATURES SLIGHTLY COLDER THAN THE BRISTOL BAY REGION.
FURTHER EAST...SHOWERS CONTINUE OVER THE NORTHERN GULF AND PRINCE
WILLIAM SOUND...BUT WEST OF THE CHUGACH REMAINS MOSTLY DRY AS THE
MOISTURE IS DOWNSLOPED OUT AS IT CROSSES THE MOUNTAINS.

&&

.MODEL DISCUSSION...

MODELS ARE IN GOOD AGREEMENT THROUGH THE MIDTERM WITH ONLY MINOR
DISCREPANCIES IN THE PLACEMENT AND AMOUNTS OF PRECIPITATION OVER
SOUTHWEST ALASKA. THE HIGHER RESOLUTION MODELS WERE USED TO BEST
CAPTURE THE DOWNSLOPING AS THE MOISTURE CROSSES THE ALEUTIAN
RANGE. THE NAM WAS THE MODEL OF CHOICE TODAY AND FORECAST
CONFIDENCE IS ABOVE AVERAGE.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

A WAVE MOVING FROM EAST TO WEST ACROSS THE GULF OF ALASKA HAS BEEN
SUPPORTING RAIN ACROSS PRINCE WILLIAM SOUND AND THE EASTERN KENAI
PENINSULA DURING THE OVERNIGHT HOURS. THE ANCHORAGE SOUNDING THIS
MORNING INDICATES A LAYER OF DRY AIR FROM THE SURFACE TO 800
MB AND SOME CROSS BARRIER FLOW...WHICH HAS LIMITED RAINFALL TO
ISOLATED FREEZING DRIZZLE IN ANCHORAGE. A RAINY DAY IS IN ORDER
FOR THE WESTERN KENAI BEFORE THE WAVE PROGRESSES SOUTH AND
WESTWARD. A MUCH MORE ORGANIZED LOW PRESSURE SYSTEM WITH A POTENT
LOW LEVEL JET WILL ENTER THE SOUTHERN GULF OF ALASKA TUESDAY
EVENING. MEANWHILE...A RIDGE IS IN PLACE OVER THE COPPER RIVER
BASIN...AND WILL CONTINUE TO SLOWLY BUILD WESTWARD ACROSS THE
ALASKA MAINLAND OVER THE NEXT FEW DAYS. THIS RIDGE WILL BLOCK THE
GULF LOW AND LIMIT RAIN AND GUSTY WINDS TO COASTAL REGIONS TUESDAY
EVENING.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

PRECIPITATION WILL CONTINUE ACROSS THE SOUTHWEST MAINLAND TODAY AS
A FRONT PUSHES OFFSHORE BUT IS QUICKLY REPLACED BY AN UPPER LEVEL
DISTURBANCE ARRIVING FROM THE WESTERN GULF. THIS WAVE WILL
INITIALLY KEEP THE PRECIPITATION FOCUSED OVER THE BRISTOL BAY
REGION THROUGH THIS AFTERNOON AS A MIX OF RAIN AND SNOW BEFORE
SPREADING WEST TO THE KUSKOKWIM DELTA TONIGHT. PRECIPITATION TYPE
WILL THEN BECOME MORE OF A CHALLENGE AS TEMPERATURES BEGIN TO WARM
ALOFT BUT ARE SLOWER TO RESPOND AT THE SURFACE AS A RESULT OF
PERSISTENT NORTHERLY WINDS. THIS WILL LEAD TO THE POTENTIAL FOR
FREEZING RAIN ACROSS THE DELTA LATE TONIGHT INTO TUESDAY MORNING
BEFORE TEMPERATURES CLIMB ABOVE FREEZING AND ALLOW ANY ADDITIONAL
PRECIPITATION TO CHANGE OVER TO RAIN. PRECIPITATION WILL THEN
SLOWLY DIMINISH THROUGH TUESDAY NIGHT AS THE TROUGH OVER THE
EASTERN BERING SLOWLY SINKS SOUTHWARD.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

COLD NORTHERLY FLOW WILL KEEP SNOW SHOWERS FOCUSED OVER THE
EASTERN HALF OF THE BERING THROUGH TUESDAY AS THE INVERTED TROUGH
ALONG THE WEST COAST GRADUALLY EVOLVES INTO A CLOSED LOW NEAR THE
ALASKA PENINSULA. A DISTURBANCE PUSHING OFF THE SOUTHWEST COAST
WILL TEMPORARILY ENHANCE SHOWER ACTIVITY ACROSS THE PRIBILOF
ISLANDS ON TUESDAY. THE WESTERN BERING WILL REMAIN MOSTLY DRY
BENEATH HIGH PRESSURE AS ANOTHER NORTH PACIFIC LOW SLIDES JUST
SOUTH OF THE CHAIN.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...

THE GENERAL PATTERN OF RIDGING OVER MAINLAND ALASKA AND A
VERTICALLY STACKED LOW IN THE GULF WILL CONTINUE FROM MIDWEEK
THROUGH AROUND THURSDAY NIGHT BEFORE THE LOW EXITS TO THE EAST
ACROSS THE SOUTHERN PANHANDLE. THE ASSOCIATED FRONT WILL STALL
ACROSS THE NORTHERN AND CENTRAL GULF WEDNESDAY THEN GRADUALLY
DISSIPATE WEDNESDAY NIGHT AND THURSDAY. FURTHER TO THE WEST A
TROUGH WILL ROTATE NORTH ACROSS THE ALASKA PENINSULA AND INTO
BRISTOL BAY AND THE EASTERN BERING WEDNESDAY AND THURSDAY WHILE
A SECOND LOW SPINS UP SOUTH OF THE ALEUTIANS AND TRACKS EAST
ACROSS THE NORTH PACIFIC. A STRONGER LOW WILL APPROACH THE WESTERN
ALEUTIANS FRIDAY AND CENTRAL ALEUTIANS SATURDAY WITH ASSOCIATED
FRONTAL SYSTEM AND TRIPLE POINT FEATURE CROSSING THE ALASKA
PENINSULA AND ROLLING UP THE WEST COAST SUNDAY. RIDGING OUT AHEAD
OF THIS LOW WILL BUILD OVER THE GULF THIS WEEKEND THEN STRENGTHEN
OVER THE EASTERN GULF...YUKON TERRITORY AND EASTERN INTERIOR
ALASKA THROUGH THE FIRST HALF OF NEXT WEEK KEEPING TEMPERATURES IN
SOUTH CENTRAL ALASKA GENERALLY ABOVE NORMAL WHILE A SERIES OF
DISTURBANCE TRACK UP FROM THE SOUTH.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING...130 132 138 AND 352.
         HEAVY FREEZING SPRAY WARNING...180 185 412 AND 414.

&&

SYNOPSIS AND MODEL DISCUSSION...RD
SOUTHCENTRAL ALASKA...EN
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CB
LONG TERM...JER