Storm Warning 172, NWS Anchorage, AK

398 
FZAK61 PAFC 201207
OFFAER

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
307 AM AKST SUN DEC 20 2015

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.

PKZ399-210230-
307 AM AKST SUN DEC 20 2015
.SYNOPSIS FOR THE WESTERN GULF OF ALASKA...

A 970 MB LOW NEAR 57N 144W MOVES INLAND NEAR 57N 136W AT 986 MB MON
AFTERNOON. A 979 MB LOW DEVELOPS NEAR 55N 161W MON MORNING AND
MOVES TO 55N 150W TUE MORNING AND MAINTAINS STRENGTH.

$$

PKZ351-210230-
GULF OF ALASKA OFFSHORE NORTH OF 57N AND WEST OF 144W-
307 AM AKST SUN DEC 20 2015

.TODAY...NW WIND 15 TO 30 KT. SEAS 11 TO 16 FT. RAIN SHOWERS.
.TONIGHT...NW WIND 15 TO 25 KT. SEAS 8 TO 13 FT.
.MON...W WIND 20 KT. SEAS 7 TO 10 FT.
.MON NIGHT...SW WIND UP TO 20 KT. SEAS 3 TO 8 FT.
.TUE...W WIND 15 TO 30 KT. SEAS 7 TO 12 FT.
.WED...NW WIND 20 TO 35 KT. SEAS 11 TO 17 FT.
.THU...N WIND 15 TO 30 KT. SEAS 7 TO 12 FT.

$$

PKZ352-210230-
GULF OF ALASKA OFFSHORE SOUTH OF 57N NORTH OF 55N AND WEST OF
144W-
307 AM AKST SUN DEC 20 2015

...GALE WARNING TODAY...

.TODAY...NW WIND 30 TO 45 KT DIMINISHING TO 25 TO 35 KT IN THE
AFTERNOON. SEAS 14 TO 27 FT.
.TONIGHT...W WIND 30 KT. SEAS 10 TO 17 FT.
.MON...SW WIND 25 KT. SEAS 7 TO 12 FT.
.MON NIGHT...SW WIND 20 TO 35 KT. SEAS 11 TO 19 FT.
.TUE THROUGH WED...NW WIND 25 TO 40 KT. SEAS 12 TO 20 FT.
.THU...N WIND 15 TO 30 KT. SEAS 9 TO 14 FT.

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
452 AM AKST SAT DEC 19 2015

.ANALYSIS AND UPPER LEVELS...

THE PROGRESSIVE PATTERN CONTINUES THIS MORNING WITH A NEARLY ZONAL
TRANSPACIFIC JET AT MID LATITUDES...AND AN UPPER LOW EXTENDING
FROM KAMCHATKA TO THE CENTRAL BERING...WITH AN EXTENSION OVER
KODIAK ISLAND. AN UPPER RIDGE IS CENTERED ALONG THE GULF COAST
THAT EXTENDS OVER SOUTH CENTRAL AND THE AK RANGE. AT THE
SURFACE...A LARGE LOW IS OVER THE CENTRAL BERING WITH A FRONT OVER
SW AK. A TRIPLE POINT LOW EXTENDS FROM THE SW AK FRONT ACROSS
KODIAK ISLAND AND THE BARRENS AND THEN INTO THE CENTRAL GULF.
STORMS WITH HURRICANE FORCE GUSTS ARE LOCATED ALONG THE SOUTHERN
FLANK OF THE BERING LOW...AND GALES ARE ON THE LEADING EDGE OF THE
GULF FRONT. SNOW SHOWER ACTIVITY IS ALONG THE SOUTHWEST AK
COAST...ALTHOUGH AREAS OF FOG ARE FOUND FARTHER INLAND.

&&

.MODEL DISCUSSION...

AS IS OFTEN THE CASE...MODELS ARE STRUGGLING WITH THE
DEVELOPMENT...PLACEMENT...AND MOVEMENT OF THE TRIPLE POINT LOW
CURRENTLY OVER KODIAK ISLAND AND THE BARRENS. THE GFS WAS USED AS
A CONSENSUS SOLUTION...SLOWLY BRINGING THE LOW INTO THE NORTHERN
GULF THIS WEEKEND WHERE IT STALLS. THIS SOLUTION ALSO BRINGS THE
BERING LOW INLAND NEAR NUNIVAK ISLAND TONIGHT...HAVING IT
DISSIPATE ON SUN OVER SW AK. A NEW LOW FROM THE NORTH PACIFIC
DRAGS A FRONT OVER WESTERN AK THIS WEEKEND...AND YET ANOTHER LOW
MOVES INTO THE CENTRAL ALEUTIANS ON SUN. BECAUSE OF THE STRUGGLING
MODELS...FORECAST CONFIDENCE OVER THE EASTERN DOMAIN IS BELOW
AVERAGE...BUT SLIGHTLY BETTER OVER THE WEST.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE UPPER LOW SPINNING UP NEAR KODIAK ISLAND WILL WORK ITS WAY
EASTWARD THROUGH SUNDAY. THE ASSOCIATED SURFACE LOW NEAR THE
BARREN ISLANDS WILL BECOME VERTICALLY STACKED WITH THE UPPER LOW
THIS EVENING OVER THE NORTH CENTRAL GULF. THE LOW WILL THEN STALL
LATE SUNDAY...THOUGH EXACTLY WHERE THIS WILL BE IS UNCERTAIN DUE
TO THE NUMERICAL GUIDANCE HAVING QUITE A SPREAD. MOST OF THE
PRECIPITATION WITH THIS SYSTEM WILL FALL NEAR THE GULF COAST WITH
VERY LITTLE PRECIPITATION MAKING IT INLAND. DUE TO THE DIFFERING
MODEL GUIDANCE THE FORECAST CONFIDENCE IS QUITE LOW...ESPECIALLY
FOR THE MARINE FORECASTS WHERE THE WIND DIRECTIONS AND SPEEDS
ARE QUITE DIFFERENT IN SEVERAL OF THE MODELS.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
A FRONT/DEFORMATION BAND WILL WEAKEN QUICKLY THIS MORNING FROM THE
LOWER KUSKOKWIM VALLEY THROUGH KAMISHAK BAY ENDING STEADY SNOW IN
THESE AREAS. FOR THE REMAINDER OF THE WEEKEND A SHOWERY REGIME
WILL STAY IN PLACE AS THE UPPER LEVEL LOW PRESSURE LINGERS.
SCATTERED SHOWERS WILL HANG AROUND IN MOST PLACES AS THE SYSTEM
SLOWLY WEAKENS OVERHEAD. WINDS WILL CONTINUE TO REMAIN ON THE
LIGHTER SIDE WITH TEMPERATURES MODERATED IN MOST AREAS...SLIGHTLY
AT OR ABOVE CLIMATOLOGICAL NORMALS...IN THE 20S. SLACK FLOW AND
CLEARING CLOUDS HAVE PROMOTED FOG DEVELOPMENT IN THE GREATER
BRISTOL BAY AREA...EXPECT AREAS OF FOG TO STICK AROUND THROUGH THE
MORNING HOURS WITH SOME IMPROVEMENT IN THE AFTERNOON. TOWARD EARLY
NEXT WEEK...THE PREVIOUS SYSTEM CONTINUES TO WEAKEN WHILE A COLDER
AIRMASS SLIDES IN FROM THE INTERIOR.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE LARGE LOW PRESSURE OVER THE NORTHERN BERING SEA CONTINUES TO
WEAKEN...BUT THE WIND FIELD STILL PACKS QUITE A PUNCH. COLD AIR
WRAPPING INTO THE SYSTEM FROM EASTERN RUSSIA IS PROMOTING STEEP
LAPSE RATES IN THE LOW LEVELS...ALLOWING FOR NEARLY ALL THE WINDS
IN THIS AREA TO MIX DOWN TO THE SURFACE. HIGH WINDS WILL BE THE
MAIN FOCUS FOR THE PRIBILOF ISLANDS TODAY WHERE GUSTS TO 75 MPH
WILL CONTINUE BEFORE DIMINISHING SLIGHTLY IN THE AFTERNOON.
OTHERWISE...GUSTY WESTERLY WINDS AND SHOWERY CONDITIONS WILL
ENCOMPASS MOST OF THE BERING. SUNDAY INTO MONDAY...A STALLING
FRONTAL BOUNDARY WILL SPAWN A COMPACT LOW PRESSURE SYSTEM OVER THE
CENTRAL ALEUTIANS WHILE SENDING A FRONT EASTWARD.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THERE WILL BE A WEAK LOW IN THE IN THE NORTHERN GULF ON SUNDAY
MORNING. WHILE AN UPSTREAM LOW PRESSURE SYSTEM IN THE BRISTOL BAY
AREA MOVES INTO THE GULF BY MONDAY MORNING AND PHASES WITH THE
REMNANTS OF LOW IN THE NORTHERN GULF. THESE TWO SYNOPTIC
FEATURES WILL TRANSITION INTO A BROAD AREA OF LOW PRESSURE OVER
THE NORTHERN GULF BEFORE GRADUALLY MOVING TO THE SOUTHEAST BY
TUESDAY. THE MAJORITY OF THE PRECIPITATION WILL OCCUR ALONG THE
NORTHERN GULF COASTAL COMMUNITIES IN THE FORM OF SNOW. THE BARREN
ISLAND REGION WILL HAVE RAIN AND SNOW EXCEPT FOR ALL RAIN FOR
KODIAK ISLAND WITH TEMPERATURES IN THE UPPER 30S TO LOWER 40S. THE
SOUTHCENTRAL REGION WILL HAVE COOLER TEMPERATURES AND DRIER
CONDITIONS WITH OFFSHORE NORTHERLY WINDS BY MONDAY THROUGH THE
MIDWEEK.

ON THE BERING SEA SIDE A STORM FORCE LOW DEVELOPS AND TRACKS
ACROSS THE CENTRAL ALEUTIANS NEAR ADAK BY SUNDAY AFTERNOON. THIS
WILL BRING GALE FORCE SOUTHEASTERLY WINDS AHEAD OF THE SYSTEM
WITH STORM FORCE WESTERLY WINDS SOUTH OF CENTRAL ALEUTIANS
HEADING INTO NEXT WEEK. THERE WILL BE A TRIPLE POINT LOW FORMING
NEAR THE SHUMAGIN ISLANDS OUT AHEAD OF THIS SYSTEM ON MONDAY.
THESES SYNOPTIC FEATURES WILL CONTINUE TO TRACK EASTWARD INTO THE
GULF BY MIDWEEK WITH A STRONG ZONAL JET STREAM SOUTH OF THE CHAIN.
THE MODELS CONTINUE TO STRUGGLE WITH THIS SYSTEM AND THE ECMWF IS
THE OUTLIER WITH MOVING THIS SYSTEM FASTER TO THE EAST COMPARED TO
THE GFS WHICH WAS THE PREFERRED MODEL WITH A SLOWER STORM TRACK
WITH THIS SYSTEM. THE FORECAST CONFIDENCE IS AVERAGE AT BEST WITH
PREVIOUS MODEL RUNS. THE NEXT SYSTEM ENTERING THE AREA WILL BE A
NORTH PACIFIC LOW FORMING BY WEDNESDAY SOUTH OF THE WESTERN
ALEUTIANS. THE ECMWF REMAINS AN OUTLIER IN MOVING THIS SYSTEM
RAPIDLY INTO THE NORTHERN BERING THROUGH THE MIDWEEK. THE GFS/WPC
GUIDANCES HAVE BETTER AGREEMENT WITH THE PLACEMENT OF THIS SYSTEM
THAN THE ECMWF. BY WEDNESDAY EVENING THIS SYSTEM WILL BE OVER THE
WESTERN ALEUTIANS AS THE JET STREAM WILL BE TRANSITIONING TO A
STRONG SOUTH TO NORTH MERIDIONAL FLOW. THIS WILL AID IN THE RAPID
INTENSIFICATION OF THIS NORTH PACIFIC LOW. THIS SYSTEM WILL BRING
WIDESPREAD RAIN AND STRATUS WITH GUSTY WINDS ALONG THE CHAIN AND
THE LOWER BERING SEA THROUGH THE MIDWEEK.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH WIND WARNING...195.
MARINE...STORMS...177 179 412 413 414
 GALES...119 120 125 127 130 131 132 136 137 139
         150 155 165 170 171 172 173 174 175 176
         178 180 181 185 351 352

&&

SYNOPSIS AND MODEL DISCUSSION...DS
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...ML
LONG TERM...PD