Gale Warning 491, NWS Anchorage, AK

018 
FZAK62 PAFC 092313
OFFALU

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
313 PM AKDT SUN AUG 9 2015

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.

PKZ499-101345-
313 PM AKDT SUN AUG 9 2015
.SYNOPSIS FOR CENTRAL BERING SEA...

A 1012 MB LOW NEAR 50N 176E WEAKENS TO 1016 MB AS IT DRIFTS TO
NEAR 50N 180 MON MORNING AND DISSIPATING BY MON AFTERNOON. WEAK
HIGH PRESSURE WILL ENCOMPASS THE BERING THROUGH LATE MON NIGHT.

$$

PKZ411-101345-
BERING SEA OFFSHORE WEST OF 180 AND EAST OF THE INTERNATIONAL
DATELINE-
313 PM AKDT SUN AUG 9 2015

.TONIGHT...W WIND 10 TO 20 KT. SEAS 4 FT. PATCHY FOG.
.MON...W WIND 10 TO 20 KT. SEAS 3 TO 6 FT. PATCHY FOG.
.MON NIGHT...SW WIND 10 TO 20 KT. SEAS 3 TO 6 FT.
.TUE...S WIND 10 TO 20 KT. SEAS 3 TO 6 FT.
.TUE NIGHT...S WIND 10 TO 20 KT. SEAS 4 FT.
.WED THROUGH THU...S WIND UP TO 15 KT. SEAS 4 FT.
.FRI...SW WIND UP TO 15 KT. SEAS 4 FT.

$$

PKZ412-101345-
BERING SEA OFFSHORE 171W TO 180 AND NORTH OF 56N-
313 PM AKDT SUN AUG 9 2015

.TONIGHT...W WIND 10 TO 20 KT. SEAS 5 FT. PATCHY FOG.
.MON...SW WIND 10 TO 20 KT. SEAS 5 FT. PATCHY FOG.
.MON NIGHT...W WIND 10 TO 20 KT. SEAS 5 FT. PATCHY FOG.
.TUE...W WIND 10 TO 20 KT. SEAS 5 FT.
.TUE NIGHT...SW WIND 15 KT. SEAS 5 FT.
.WED THROUGH FRI...SE WIND UP TO 15 KT. SEAS 4 FT.

$$

PKZ413-101345-
BERING SEA OFFSHORE 171W TO 180 AND SOUTH OF 56N-
313 PM AKDT SUN AUG 9 2015

.TONIGHT...VARIABLE WIND 10 KT. SEAS 4 FT. PATCHY FOG.
.MON...VARIABLE WIND 10 KT. SEAS 4 FT. PATCHY FOG.
.MON NIGHT...W WIND 10 TO 15 KT. SEAS 4 FT. PATCHY FOG.
.TUE...SW WIND UP TO 15 KT. SEAS 4 FT.
.TUE NIGHT...S WIND UP TO 15 KT. SEAS 4 FT.
.WED...S WIND UP TO 15 KT. SEAS 3 FT.
.THU...SE WIND 10 KT. SEAS 2 FT.
.FRI...SW WIND UP TO 15 KT. SEAS 3 TO 5 FT.

$$

PKZ414-101345-
BERING SEA OFFSHORE EAST OF 171W-
313 PM AKDT SUN AUG 9 2015

.TONIGHT...NW WIND 10 TO 15 KT. SEAS 6 FT. PATCHY FOG.
.MON...VARIABLE WIND 15 KT. SEAS 4 FT. PATCHY FOG.
.MON NIGHT...W WIND 10 TO 20 KT. SEAS 3 FT. PATCHY FOG.
.TUE...W WIND 15 KT. SEAS 4 FT.
.TUE NIGHT...W WIND UP TO 15 KT. SEAS 4 FT.
.WED...S WIND 10 KT. SEAS 3 FT.
.THU...E WIND UP TO 10 KT. SEAS 2 FT.
.FRI...SW WIND 10 KT. SEAS 3 TO 4 FT.

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
413 PM AKDT SAT AUG 8 2015

.ANALYSIS AND UPPER LEVELS...
THE UPPER RIDGE HAS BEEN SHUNTED TO THE EAST AS A TROUGH
ASSOCIATED WITH A UPPER LOW OVER THE CHUKCHI SEA PUSHES SOUTHEAST ACROSS
THE GULF OF ANADYR. THIS IS SETTING UP BROAD MOIST SOUTHWESTERLY
FLOW ALOFT OVER THE THE SOUTHERN MAINLAND WHICH IS IN THE PROCESS
OF PHASING WITH A MOIST SOUTHWESTERLY JET EXTENDING FROM THE
CENTRAL PACIFIC TO THE EASTERN ALEUTIANS. RAIN ASSOCIATED WITH A
SURFACE OCCLUDED FRONT IN MOVING INTO SOUTHWEST ALASKA AND
BRISTOL BAY WITH HIGH CLOUDS SPREADING ACROSS SOUTHCENTRAL
ALASKA. THE TRAILING COLD FRONT EXTENDS SOUTHWEST ACROSS THE
NORTHEAST PACIFIC WHERE STRONG DYNAMICS ARE PRODUCING
THUNDERSTORMS ALONG ITS LEADING EDGE.

&&

.MODEL DISCUSSION(THROUGH MON AFTERNOON)...
MODELS OVERALL ARE IN GOOD SYNOPTIC AGREEMENT AND REASONABLE. THE
EXCEPTION WOULD BE THAT THE RAIN IS A BIT AHEAD OF SCHEDULE OVER
SOUTHWEST ALASKA AND IS MOVING INTO THE COOK INLET REGION FASTER
THAN ANY OF THE MODELS WERE SHOWING. THE 18Z NAM IS ALSO INITIALLY
TOO SLOW ON MOVING THE QPF(RAIN) ALONG. THE GEM REGIONAL AND GFS20
APPEAR TO HAVE OVERALL BETTER QPF PATTERN AND TIMING.

&&

.FIRE WEATHER...
FIRE WEATHER CONCERNS WILL BE MITIGATED BY CLOUD COVER AHEAD OF A
MOIST SYSTEM APPROACHING THE MAINLAND TODAY. THE COPPER RIVER WILL
GET RELATIVE HUMIDITY VALUES DOWN INTO THE 30S THIS AFTERNOON
ALONG WITH SOME GUSTY SOUTHERLY WINDS BUT SHOULD STAY ABOVE RED
FLAG CRITERIA. THE NEXT SYSTEM ON SUNDAY WILL BRING A WIDESPREAD
WETTING RAIN TO MOST AREAS.

&&

.HYDROLOGY...
THE RELEASE OF WATER FROM ICEBERG LAKE...A GLACIER DAMMED LAKE ON
THE NELCHINA GLACIER...HAS STOPPED. WATER LEVELS IN THE NELCHINA RIVER
AND TAZLINA LAKE HAVE RISEN ABOUT 2 TO 3 FEET AND ARE NOW RECEDING.
RIVER LEVELS ON THE TAZLINA RIVER AT THE RICHARDSON HIGHWAY BRIDGE
CONTINUE TO RISE AS A RESULT OF THIS RELEASE AND ARE EXPECTED TO CREST BY
MONDAY MORNING THEN RECEDE.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE ONSET OF RAINFALL INTO SOUTHCENTRAL ALASKA IS EVOLVING MORE
RAPIDLY THIS AFTERNOON THAN PREVIOUS FORECASTS AND THE MODELS HAVE
BEEN INDICATING SO FAR TODAY. RADAR AND SATELLITE DATA THIS
AFTERNOON IS INDICATING THE INITIAL BAND OF RAINFALL HAS MOVED
OVER KODIAK ISLAND AND AS OF ISSUANCE TIME MOVING ACROSS KENNEDY
ENTRANCE INTO THE KENAI PENINSULA. THIS SHOULD BRING UP THE
TIMING OF RAINFALL INTO UPPER COOK INLET BY LATE THIS EVENING WITH
STRATIFORM RAIN DEVELOPING INTO THE COPPER RIVER BASIN BY EARLY
SUNDAY MORNING. THROUGH SUNDAY NIGHT...THE HEAVIEST RAINFALL
AMOUNTS ARE EXPECTED MAINLY IN THE SUSITNA VALLEY AND ALONG PRINCE
WILLIAM SOUND WHERE THE LOW TO MID LEVEL FLOW...AIDED BY
DIFFLUENCE ALOFT...WILL BE THE BEST FOR OROGRAPHIC ENHANCEMENT OF
PRECIPITATION. AS THE UPPER LEVEL SHORTWAVE MOVES THROUGH THE
AREA BY MONDAY...CONDITIONS WILL DRY OUT OVER THE WESTERN HALF OF
THE REGION AS DRIER AIR FILTERS IN FROM THE NORTHWEST.

WITH THE RIDGE BUILDING INTO THE GULF OF ALASKA AND THE UPPER
TROUGH MOVING THROUGH THE AREA...WINDS ARE EXPECTED TO INCREASE
TO NEAR GALE FORCE THROUGH SHELIKOF STRAIT AND THROUGH PRINCE
WILLIAM SOUND ON SUNDAY.

&&

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

IT APPEARS AS THOUGH MODELS HAVE CAUGHT UP WITH THE TIMING OF
RAINFALL TODAY ACROSS SOUTHWEST ALASKA. THE GOING FORECAST FOR
TONIGHT INTO SUNDAY IS ON TRACK WITH STEADY RAIN DEVELOPING FROM
WEST TO EAST ACROSS THE AREA THROUGH THE OVERNIGHT...HEAVIEST NEAR
AND ALONG THE KUSKOKWIM RIVER CORRIDOR. THERE IS SOME UNCERTAINTY
REGARDING AN AREA OF DEFORMATION OVER INLAND KUSKOKWIM DELTA
SUNDAY...WITH THE GFS MORE BULLISH ON QPF IN THE BETHEL AREA AS
THE UPPER LEVEL DISTURBANCE LAGS BEHIND THE LOWER-LEVEL FEATURES.
NEVERTHELESS...CONDITIONS SHOULD GRADUALLY IMPROVE FROM WEST TO
EAST LATE OVERNIGHT THROUGH MONDAY WITH THE EXCEPTION OF THE
ALASKA RANGE...BEFORE A WEAKER AND PROGRESSIVE DISTURBANCE IN
NORTHWEST FLOW ALOFT BRINGS A CHANCE OF SHOWERS TO THE KUSKOKWIM
DELTA AND VALLEY REGIONS LATER MONDAY AFTERNOON INTO MONDAY
NIGHT.

&&

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

SURFACE TROUGH LOCATED FROM NEAR BETHEL TO SAINT PAUL TO NEAR
SHEMYA WILL GRADUALLY WEAKEN WITH AN EMBEDDED WEAK LOW NEAR SAINT
PAUL RACING INLAND OVER THE KUSKOKWIM DELTA TONIGHT...WITH THE
WEAK LOW NEAR SHEMYA MOVING SOUTH AND THEN EAST TO THE SOUTH OF
THE CENTRAL ALEUTIANS WHILE WEAKENING. ALONG THE SOUTH SIDE OF
THIS TROUGH AS IT MOVES SLOWLY SOUTH AND EAST...GOOD JET SUPPORT
WILL ALLOW FOR AN AREA OF GALE FORCE WINDS TONIGHT IN THE FAR
SOUTHEASTERN OFFSHORE REGION (ZONE 414) OF THE BERING...POSSIBLY
CLIPPING THE COASTAL WATERS ON THE NORTH SIDE OF THE COASTAL
ALASKA PENINSULA ZONE AND SOUTH AND WEST OF CAPE NEWENHAM.

MODELS ARE NOW SUGGEST A DISTURBANCE MOVING WEST TO EAST ACROSS
THE ISLAND CHAIN MONDAY INTO MONDAY NIGHT WILL KEEP THE BULK OF
RAIN/SHOWERS CONFINED MAINLY TO THE SOUTH OF THE EASTERN ALEUTIANS
AND ALASKA PENINSULA.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
A PRETTY PROGRESSIVE PATTERN BEGINS TO SET UP OVER THE AREA...AS
WESTERLY FLOW BEGINS TO SET UP OVER MUCH OF THE REGION BEHIND THE
EXITING TROUGH TO THE EAST. THIS TYPE OF PATTERN MEANS THAT
INDIVIDUAL STORMS/WAVES TEND TO BE ON THE FASTER AND WEAKER END OF
THE SCALE (RELATIVELY) FOR THE VOLATILE NORTH PACIFIC. THE
UPCOMING WEEK LOOKS LIKE IT WILL FOLLOW THIS GENERAL TEMPLATE...
WITH SENSIBLE WEATHER DICTATED LARGELY BY AN ALTERNATING SEQUENCE
OF SHORTWAVE TROUGHS AND SHORTWAVE RIDGES. THERE SHOULD BE SOME
BREAKS OF SUN BY MIDWEEK ACROSS THE MAINLAND...BUT NO HEATWAVES OR
HUGE RAIN- OUTS ANTICIPATED AT THIS TIME. OVERALL...CONSIDERING
THAT AUGUST IS HISTORICALLY A RAINY MONTH FOR MOST LOCATIONS IN
SOUTHERN ALASKA...NEXT WEEK SHOULD BE NICER THAN NORMAL ACROSS
MAINLAND LOCATIONS.

THE BIGGEST AREA OF UNCERTAINTY REMAINS THE EVENTUAL FATE OF A
TROPICAL DISTURBANCE CURRENTLY SOUTHEAST OF JAPAN. GLOBAL MODELS
CONTINUE TO STRUGGLE WITH THE OVERALL TRACK OF THIS SYSTEM...
EITHER BRINGING THE REMNANTS INTO THE ALEUTIAN REGION OR KEEPING
IT SOUTH. THE LATEST GUIDANCE IS NOW SUGGESTING A MORE NORTHERLY
TRACK INTO THE WESTERN/CENTRAL ALEUTIANS OVER THE WEEKEND. WITH
SUCH UNCERTAINTY AND INCONSISTENCY IN THE MODELS... FORECAST
CONFIDENCE IN THE LONG TERM WILL REMAIN BELOW AVERAGE.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE 180.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...BC
SOUTHCENTRAL ALASKA...RF
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CC
LONG TERM...TP