Gale Warning 120, NWS Anchorage, AK

322 
FZAK62 PAFC 200004
OFFALU

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
304 PM AKST FRI FEB 19 2016

OFFSHORE WATERS FORECAST FOR THE BERING SEA

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.

PKZ499-201445-
304 PM AKST FRI FEB 19 2016
.SYNOPSIS FOR CENTRAL BERING SEA...

A 965 MB LOW NEAR 60N 171E DISSIPATES THIS EVENING. A 974 MB LOW
NEAR 52N 158W MOVES TO 58N 160W SUN AFTERNOON AT 982 MB. A FRONT
ENTERS THE FAR WESTERN ALEUTIANS LATE SUN NIGHT.

$$

PKZ411-201445-
BERING SEA OFFSHORE WEST OF 180 AND EAST OF THE INTERNATIONAL
DATELINE-
304 PM AKST FRI FEB 19 2016

...HEAVY FREEZING SPRAY WARNING TONIGHT...

.TONIGHT...W WIND 10 TO 25 KT. SEAS 11 TO 16 FT. HEAVY FREEZING
SPRAY W OF 174E IN THE EVENING.
.SAT...NW WIND 10 TO 20 KT. SEAS 10 FT. FREEZING SPRAY.
.SAT NIGHT...N WIND 15 TO 25 KT. SEAS 9 FT. FREEZING SPRAY.
.SUN...N WIND UP TO 20 KT. SEAS 8 FT.
.SUN NIGHT...E WIND 10 TO 25 KT. SEAS 7 FT.
.MON THROUGH WED...NE WIND 20 TO 30 KT. SEAS 9 TO 17 FT.

$$

PKZ412-201445-
BERING SEA OFFSHORE 171W TO 180 AND NORTH OF 56N-
304 PM AKST FRI FEB 19 2016

.TONIGHT...NW WIND 10 TO 20 KT. SEAS 13 FT. FREEZING SPRAY.
.SAT...NE WIND 15 TO 25 KT. SEAS 11 FT. FREEZING SPRAY.
.SAT NIGHT...N WIND 20 TO 30 KT. SEAS 11 FT. FREEZING SPRAY.
.SUN...N WIND 15 TO 30 KT. SEAS 9 FT.
.SUN NIGHT...N WIND UP TO 20 KT. SEAS 6 TO 9 FT.
.MON...E WIND 10 TO 25 KT. SEAS 4 TO 8 FT.
.TUE THROUGH WED...NE WIND 35 KT. SEAS 10 TO 18 FT.

$$

PKZ413-201445-
BERING SEA OFFSHORE 171W TO 180 AND SOUTH OF 56N-
304 PM AKST FRI FEB 19 2016

...GALE WARNING TONIGHT...

.TONIGHT...NW WIND 20 TO 35 KT. SEAS 11 TO 14 FT. FREEZING SPRAY.
.SAT...NW WIND 15 TO 30 KT. SEAS 10 TO 13 FT. FREEZING SPRAY W OF
174W.
.SAT NIGHT...N WIND 20 TO 30 KT. SEAS 11 FT. FREEZING SPRAY W OF
177W.
.SUN...N WIND 10 TO 25 KT. SEAS 9 FT.
.SUN NIGHT...N WIND UP TO 15 KT. SEAS 6 TO 9 FT.
.MON...E WIND 15 TO 30 KT. SEAS 7 TO 12 FT.
.TUE THROUGH WED...N WIND 25 TO 35 KT. SEAS 13 TO 21 FT.

$$

PKZ414-201445-
BERING SEA OFFSHORE EAST OF 171W-
304 PM AKST FRI FEB 19 2016

...HEAVY FREEZING SPRAY WARNING SATURDAY NIGHT...

.TONIGHT...NE WIND 25 KT. SEAS 9 TO 13 FT. FREEZING SPRAY N OF 56N.
.SAT...N WIND 25 KT. SEAS 10 FT. FREEZING SPRAY N OF 56N.
.SAT NIGHT...N WIND 20 TO 30 KT. SEAS 10 FT. HEAVY FREEZING SPRAY
N OF 58N.
.SUN...N WIND 25 KT. SEAS 7 TO 11 FT.
.SUN NIGHT...NW WIND 10 TO 20 KT. SEAS 6 TO 9 FT.
.MON...SE WIND 10 TO 25 KT. SEAS 4 TO 8 FT.
.TUE THROUGH WED...NE WIND 20 TO 35 KT. SEAS 10 TO 18 FT.

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
450 PM AKST THU FEB 18 2016

.ANALYSIS AND UPPER LEVELS...THE PATTERN IS DEFINITELY MORE
DYNAMIC AND INTERESTING THAN IT HAS BEEN IN THE PAST FEW WEEKS.
FIRST...THE REMNANTS OF THE FRONT THAT STALLED OVER THE SOUTHWEST
IS FALLING APART IN PLACE. SNOW HAS ALL BUT ENDED ACROSS THE
AK PENINSULA WITH JUST A FEW LINGERING SHOWERS HOLDING ON IN
THE TRAILING GUSTY NORTHWEST FLOW. NEXT UP IS A FAIRLY BROAD LOW
OUT OVER THE WESTERN BERING. WHILE THE LOW ITSELF IS NOW SLOWLY
FILLING...IT HAS PUSHED AN ELONGATED FRONTAL BOUNDARY ACROSS MUCH
OF THE CENTRAL BERING. THE PRIBILOF ISLANDS ARE JUST EAST OF THIS
BOUNDARY AT THIS TIME. BUT AS IT DRIFTS EAST THEY SHOULD START TO
SEE THE SOUTHEAST WINDS INCREASE AND SNOW PICK UP IN INTENSITY. A
WINTER WEATHER ADVISORY IS IN EFFECT FOR THE ISLANDS. ON THE
SOUTHERN END OF THIS BOUNDARY...A TRIPLE POINT LOW IS STARTING TO
TAKE SHAPE. THIS LOW WILL HELP TO REINFORCE SOME WARM SOUTHEAST
FLOW OVER THE EASTERN BERING AND SOME COLDER NORTHWEST FLOW OVER
THE CENTRAL ALEUTIANS. THIS SHOULD SET THE STAGE FOR A FAIRLY
SIGNIFICANT SNOW EVENT FOR NIKOLSKI WITH STORM-FORCE NORTHERLY
WINDS. A BLIZZARD WARNING HAS BEEN ISSUED FOR THAT AREA.

MEANWHILE...HIGH PRESSURE CONTINUES TO KEEP THINGS RELATIVELY
QUIET IN THE EAST. SOME LOW STRATUS LINGERS OVER THE COPPER RIVER
BASIN...BUT THIS SHOULD ONCE AGAIN LIFT SOMEWHAT LATE THIS
AFTERNOON. IT COULD REDEVELOP OVERNIGHT AS THE PATTERN WILL BE SLOW
TO CHANGE. THE MAIN FEATURE OF INTEREST IS THE WEAKENING LOW NEAR
KODIAK. EARLIER TODAY IT WAS DIVIDING THE ISLAND IN TWO WITH WARM
SOUTHEAST FLOW NEAR KODIAK CITY PROVIDING RAIN WHILE THE SOUTH END
OF THE ISLAND WAS SNOW UNDER COLD NORTHWEST FLOW. THE
SOUTHEASTERLIES HAVE WON THIS BATTLE AND NOW ALL LOCATIONS HAVE
GONE OVER TO RAIN. WEAK OFFSHORE FLOW WILL CONTINUE FOR THE
MAINLAND AS AN OLD FRONTAL BOUNDARY PIVOTS WEST FROM THE GULF
TOWARD THE EASTERN KENAI PENINSULA.

&&

.MODEL DISCUSSION...SYNOPTICALLY...ALL MODELS REMAIN IN PRETTY
GOOD AGREEMENT. BUT DUE TO THE NATURE OF THIS FORECAST WITH MANY
FINE DETAILS MAKING DRAMATIC DIFFERENCES...THE HIGHER RESOLUTION
MODELS WERE GENERALLY PREFERRED. THE KEY DIFFERENCES ARE WITH THE
EXACT LOCATION OF THE DEFORMATION BAND NEAR THE PRIBS AND HOW FAR
WEST THE SOUTHEASTERLY FLOW CAN PUSH INTO THE CENTRAL ALEUTIANS.
THE 18Z NAM DID COME IN A BIT FURTHER WEST WITH THE COLD AIR FOR
THE CENTRAL ALEUTIANS. BUT EVEN WITH THAT SHIFT...NIKOLSKI WOULD
REMAIN IN SOME OF THE HEAVIEST BANDS OF SNOW. FOR THE PRIBS...THE
NAM WAS BY FAR THE COLDEST WHICH WOULD RESULT IN MORE SNOW AND
BETTER POTENTIAL FOR BLOWING SNOW. A MODEL AVERAGE WAS USED IN
HANDLING THIS IN ORDER TO NOT REFLECT THE MORE EXTREME SOLUTION.

THEN WE SHIFT OUR ATTENTION TO THE POTENTIAL FOR PRECIPITATION
OVER SOUTH CENTRAL OVER THE WEEKEND. THE MODELS HAVE BEEN GOING
BACK AND FORTH WITH THIS EVENT...BUT THEY ARE STARTING TO TREND IN
A SIMILAR DIRECTION. SEE THE LONG TERM DISCUSSION FOR DETAILS.

&&

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

THE VERTICALLY STACKED LOW TO THE SOUTHEAST OF KODIAK ISLAND WILL
CONTINUE TO DRIFT AROUND IN THAT GENERAL LOCATION TONIGHT THEN
PULL BACK TO THE WEST FRIDAY TO DISSIPATE JUST SOUTH OF KODIAK
ISLAND FRIDAY EVENING. THE FRONT ASSOCIATED WITH THIS LOW WILL
REMAIN STRETCHED OVER OR NEAR KODIAK ISLAND KEEPING PRECIPITATION
GOING THROUGH FRIDAY NIGHT. ELSEWHERE IN SOUTH CENTRAL ALASKA THE
WEATHER WILL REMAIN GENERALLY COOL AND DRY WITH BREEZY NORTH TO
NORTHEAST OUTFLOW WINDS THROUGH TERRAIN GAPS. THE NEXT LOW COMING
IN FROM THE WEST AND BRINGING A GOOD SUPPLY OF COLD AIR ALOFT
WITH IT WILL TRACK SOUTH OF THE ALASKA PENINSULA FRIDAY NIGHT
WITH ITS ASSOCIATED FRONT LIFTING NORTH INTO THE SOUTHWEST GULF
LATE FRIDAY NIGHT THROUGH SATURDAY MORNING AND TO THE CENTRAL GULF
SATURDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE FRONT THAT HAD STALLED OVER SOUTHWEST ALASKA IS RAPIDLY
DIMINISHING WHICH WILL HELP TO CLEAR OUT THE REMAINING SNOW AROUND
BRISTOL BAY THIS EVENING. THE LOW SOUTH OF THE ALASKA PENINSULA
WILL THEN BE PUSHED NORTH LATE FRIDAY BRINGING MORE WARM AIR FROM
THE SOUTHEAST. THE LOW WILL REMAIN SOUTH KEEPING MOST OF THE
PRECIPITATION AROUND BRISTOL BAY AND THE ALASKA PENINSULA.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE MAIN CONCERN OVER THE BERING AND ALEUTIANS IS WHERE THE
DEFORMATION ZONE WILL SETUP. SOME OF THE MODELS HAVE IT OVER THE
PRIBILOF ISLANDS AND STRETCHING SOUTH OVER THE NIKOLSKI AREA.
WHILE OTHERS HAVE THE BAND FURTHER TO THE WEST. IT LOOKS LIKE THE
MORE EASTERN SOLUTIONS WILL HAPPEN WHICH WILL BRING SNOW AND
STRONG WINDS TO THE PRIBILOF ISLANDS AND BLIZZARD CONDITIONS WITH
SEVERAL INCHES OF SNOW NEAR NIKOLSKI. AREAS EAST OF THE
DEFORMATION ZONE LIKE UNALASKA LOOK TO STAY OUT OF THE HEAVY SNOW
AND WINDS. THE WORST CONDITIONS WILL DIMINISH FRIDAY AND THEN A
PATTERN OF NORTH TO WEST FLOW WILL DOMINATE THE BERING AND
ALEUTIANS BRINGING SNOW SHOWERS TO THE AREA.

&&

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

THE MAJOR WEATHER EVENT OF THE MID TO LONG TERM WILL BE ON DAY 3
WITH THE ARRIVAL OF A ROBUST FRONT INTO THE SOUTHCENTRAL ALASKA ON
SUNDAY WITH A WEAK LOW MOVING NORTHWESTWARD INTO THE KENAI
PENINSULA AND PRINCE WILLIAM SOUND SOMETIME SUNDAY
AFTERNOON/EVENING. MODELS ARE COMING INTO SOMEWHAT BETTER
AGREEMENT WITH THE TIMING AND LOCATION OF THIS EVENT...BUT WITH
THAT BEING SAID THERE IS STILL A GOOD BIT OF UNCERTAINTY WITH THE
IMPACTS TO THE INTERIOR SECTIONS OF SOUTH CENTRAL ALASKA. ALONG
THE COAST...CONFIDENCE IS HIGH FOR PERIODS OF HEAVY PRECIPITATION
TO BEGIN EARLY SUNDAY MORNING THROUGH SUNDAY NIGHT. AT SEA
LEVEL...PRECIPITATION IS EXPECTED TO REMAIN ALL RAIN WITH WET SNOW
EXPECTED INLAND AND AT HIGHER ELEVATIONS ALONG THE COASTAL
MOUNTAINS. IN INTERIOR REGIONS...THE FORECAST ON SUNDAY IS NOT AS
CLEAR CUT. ALL GUIDANCE IS INDICATING THAT WINDS AT 925 THROUGH
700 MB WILL BE STRONG ENOUGH /AT LEAST 45-65KT/ TO PUSH MOISTURE
OVER THE MOUNTAINS AND INTO UPPER COOK INLET AND THE MATANUSKA AND
LOWER SUSITNA VALLEYS. MODEL QPF VALUES CURRENTLY ARE RANGING
FROM AROUND 1-2 INCHES LIQUID EQUIVALENT IN THE GREATER ANCHORAGE
AREA ON SUNDAY. THE QUESTION IS WHAT WILL BE THE FORM OF THE
PRECIPITATION. GUIDANCE IS VARYING FROM RUN TO RUN AND MODEL TO
MODEL WITH A SPREAD BETWEEN MODELS OF AROUND AN INCH OF SNOW AT
THE LOW END UPWARDS TO 25+ INCHES AT THE HIGH END. THE MAIN
INFLUENCE ON PRECIPITATION TYPE WILL BE HOW MUCH COLD AIR REMAINS
IN THE COOK INLET REGION AS THE FRONT MOVES THROUGH AND HOW MUCH
WARM AIR ALOFT...IF ANY...MAKES IT INTO THE AREA.

WITH ALL THIS SAID...THE FORECAST IS VERY CONSERVATIVE FOR THIS
PACKAGE WITH LIKELY CHANCES OF A RAIN/SNOW MIX ALONG THE UPPER
COOK INLET REGION WITH THE CHANCE OF SOME ACCUMULATING SNOW ON
SUNDAY. LIKELY ACCUMULATIONS ARE EXPECTED IN HIGHER
TERRAIN...MAINLY ALONG COASTAL REGIONS. THE FORECAST FOR SUNDAY
WILL BEAR WATCHING OVER THE NEXT 24-48 HOURS AS THERE IS AT LEAST
THE POTENTIAL FOR A SIGNIFICANT WINTER EVENT ON SUNDAY.

DAYS 4 THROUGH 7...MODELS ARE IN GROSS AGREEMENT IN THE SYNOPTIC
PATTERN AT THE UPPER LEVELS WITH A STOUT RIDGE BUILDING ALONG THE
WEST COAST OF NORTH AMERICA FROM THE BROOKS RANGE SOUTHWARD ALONG
THE CASCADES INTO CENTRAL CALIFORNIA WITH A BROAD TROUGH OVER THE
NORTH PACIFIC/BERING SEA. THIS TROUGH IS EXPECTED TO HAVE TWO MAIN
CENTERS...ONE LOCATED ROUGHLY AROUND 45N 165W AND A SECOND CENTER
OVER THE SEA OF OHKOSK. AS WITH THE UPPER LEVELS...MODELS ARE IN
BROAD AGREEMENT WITH A SERIES OF LOWS MOVING THROUGH THE ALEUTIANS
AND THE BERING SEA THROUGH THE BROAD UPPER TROUGH WITH A SURFACE
HIGH ALONG THE SE ALASKA/BC COAST. DUE TO DIFFERENCES IN
TIMING...STRENGTH...AND POSITIONS WITH THESE SYSTEMS THE DAY 4
THROUGH 7 FORECAST LEANS HEAVY ON THE WPC FORECAST /WHICH IS
MOSTLY THE 00Z EC ENSEMBLE/. THIS SOLUTION MOVES A 970-975 MB LOW
ALONG THE SOUTH END OF THE ALEUTIANS MONDAY AND TUESDAY BEFORE
MERGING INTO A BROAD LOW SOUTH OF THE ALASKA PENINSULA BY
THURSDAY. THIS PATTERN WILL KEEP THE KODIAK AND THE GULF COAST IN
A WET PATTERN THROUGH THE EXTENDED PERIOD.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
	PUBLIC...WINTER WEATHER ADVISORY...195 BLIZZARD WARNING...185.
	MARINE...STORM...174
 			GALE...131 150 170 172 173 175 176 177 178 179 185
 			HEAVY FREEZING SPRAY...160 178 180 185

&&

SYNOPSIS AND MODEL DISCUSSION...MO
SOUTHCENTRAL ALASKA...JR
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DK
LONG TERM...RF