Gale Warning 595, NWS Anchorage, AK

644 
FZAK62 PAFC 021144
OFFALU

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE ANCHORAGE AK
344 AM AKDT FRI OCT 2 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.

PKZ499-030200-
344 AM AKDT FRI OCT 2 2015
.SYNOPSIS FOR CENTRAL BERING SEA...
A FRONT NEAR BRISTOL BAY AND THE WESTERN GULF WILL REMAIN NEARLY
STATIONARY THROUGH MIDDAY SAT...THEN MOVE EAST INTO THE GULF.
ANOTHER FRONT OVER THE WESTERN BERING WILL WEAKEN AS IT MOVES INTO
THE EASTERN BERING LATE FRI NIGHT...THEN DISSIPATE AS IT MOVES
INTO MAINLAND ALASKA.

$$

PKZ411-030200-
BERING SEA OFFSHORE WEST OF 180 AND EAST OF THE INTERNATIONAL
DATELINE-
344 AM AKDT FRI OCT 2 2015

.TODAY...W WIND 15 TO 25 KT. SEAS 11 FT.
.TONIGHT...SW WIND 15 TO 25 KT. SEAS 9 FT. RAIN.
.SAT...SW WIND 15 TO 25 KT. SEAS 6 TO 11 FT. RAIN.
.SAT NIGHT...S WIND 15 TO 25 KT. SEAS 7 TO 12 FT.
.SUN...SW WIND 15 TO 30 KT. SEAS 9 TO 14 FT.
.MON THROUGH TUE...W WIND 15 TO 30 KT. SEAS 9 TO 15 FT.

$$

PKZ412-030200-
BERING SEA OFFSHORE 171W TO 180 AND NORTH OF 56N-
344 AM AKDT FRI OCT 2 2015

.TODAY...SW WIND 25 KT. SEAS 11 TO 14 FT. RAIN.
.TONIGHT...W WIND 15 TO 25 KT. SEAS 10 FT.
.SAT...SW WIND 20 KT. SEAS 9 FT.
.SAT NIGHT...S WIND 15 TO 25 KT. SEAS 8 FT.
.SUN...S WIND 20 TO 35 KT. SEAS 8 TO 13 FT.
.MON THROUGH TUE...W WIND 20 TO 30 KT. SEAS 11 TO 16 FT.

$$

PKZ413-030200-
BERING SEA OFFSHORE 171W TO 180 AND SOUTH OF 56N-
344 AM AKDT FRI OCT 2 2015

.TODAY...SW WIND 20 TO 30 KT. SEAS 11 FT. RAIN.
.TONIGHT...SW WIND 15 TO 25 KT. SEAS 9 FT.
.SAT...SW WIND 10 TO 20 KT. SEAS 8 FT. RAIN.
.SAT NIGHT...S WIND 10 TO 20 KT. SEAS 7 FT.
.SUN...S WIND 20 TO 35 KT. SEAS 7 TO 12 FT.
.MON THROUGH TUE...W WIND 15 TO 30 KT. SEAS 9 TO 14 FT.

$$

PKZ414-030200-
BERING SEA OFFSHORE EAST OF 171W-
344 AM AKDT FRI OCT 2 2015

.TODAY...S WIND 25 KT. SEAS 7 TO 12 FT. RAIN.
.TONIGHT...SW WIND 25 KT. SEAS 9 FT. RAIN.
.SAT...SW WIND 10 TO 20 KT. SEAS 8 FT.
.SAT NIGHT...SW WIND 10 TO 20 KT. SEAS 6 FT.
.SUN...S WIND 20 TO 35 KT. SEAS 7 TO 12 FT.
.MON THROUGH TUE...W WIND 15 TO 30 KT. SEAS 8 TO 13 FT.

$$

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
506 AM AKDT THU OCT 1 2015

.ANALYSIS AND UPPER LEVELS...

REMARKABLY QUIETER WEATHER HAS RETURNED TO ALL OF SOUTHERN
MAINLAND ALASKA THIS MORNING. HIGH PRESSURE CURRENTLY CENTERED
OVER INTERIOR SOUTHWEST ALASKA IS CONTROLLING MUCH OF THE
WEATHER OVER THE AREA...ALLOWING FOR ABUNDANT LATE SEPTEMBER
SUNSHINE TO MELT A GOOD AMOUNT OF THE RECENT SNOWFALL. ITS
DEFINITELY A NICE WAY TO END ANCHORAGES WETTEST SEPTEMBER ON
RECORD AND START OCTOBER. IN THE UPPER LEVELS...RIDGING ALOFT
INDICATIVE OF WARM AIR MOVING INTO THE UPPER LEVELS IS FURTHER
STABILIZING THE ATMOSPHERE AND KEEPING THE WEATHER QUIET FOR THE
TIME BEING.

UNFORTUNATELY ALL GOOD THINGS MUST COME TO AN END. A STRONG
VERTICALLY STACKED LOW IS INTENSIFYING OVER THE NORTHERN BERING.
THE LOW ITSELF EXPECTED TO REMAIN OUT OVER THE BERING NEAR
RUSSIA...HOWEVER IT WILL MOVE AN ASSOCIATED SURFACE COLD FRONT
IN TANDEM WITH A STRONG 160 KT JET STREAK IN THE UPPER LEVELS
TOWARDS MAINLAND ALASKA. THE FRONT AND JET STREAKS APPROACH WILL
PRODUCE RAINFALL AND STRONG WINDS...CURRENTLY BEING OBSERVED OVER
THE CENTRAL BERING AND ALEUTIANS. THIS SYSTEM WILL EVENTUALLY
BECOME THE NEXT BIG WEATHER MAKER FOR SOUTHERN ALASKA. CURRENTLY
THE FRONT IS DRAPED ACROSS THE CENTRAL BERING...MOVING THROUGH THE
ALEUTIANS NEAR ATKA.

&&

.MODEL DISCUSSION...

THE MODEL AGREEMENT FOR THIS FORECAST PACKAGE IS VERY CLOSE WITH
THE TIMING AND INTENSITY OF PRECIPITATION ASSOCIATED WITH THE
CENTRAL BERING FRONT. SOME MINOR DIFFERENCES ON THE SMALLER SCALE
ARE PRESENT...BUT DO NOT AMOUNT TO SIGNIFICANT CHANGES IN THE
FORECAST. THE ONE OUTLIER WAS THE CANADIAN MODEL...WHICH DEPICTS A
SLOWER MOVEMENT TO THE LOW IN THE NORTHERN BERING THAN THE REST OF
THE MODELS. THUS...THE NAM WAS THE MODEL OF CHOICE OWING TO ITS
HIGHER RESOLUTION.

&&

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

HIGH PRESSURE OVER SOUTHCENTRAL ALASKA WILL BRING PLENTY OF
SUNSHINE TODAY. THERE IS THE POSSIBILITY OF SOME MORNING FOG DUE
TO RECENT RAIN AND SNOW BUT THE ATMOSPHERE REMAINED MIXED THROUGH
THE EARLY PART OF THE NIGHT AND HAS DRIED OUT ENOUGH THAT ANY FOG
THAT FORMS SHOULD NOT LAST LONG.

THIS BREAK BETWEEN SYSTEMS WILL NOT LAST LONG AS A STRONG WEATHER
FRONT IN THE BERING SEA WILL MOVE OVER SOUTHCENTRAL ALASKA FRIDAY.
THIS WILL BRING WIDESPREAD RAIN TO THE REGION ONCE AGAIN.
PRECIPITATION TYPE ALONG THE ALASKA RANGE MAY START OFF AS SNOW
AND PRODUCE A FEW INCHES OF ACCUMULATION BEFORE TURNING TO ALL
RAIN. WHILE PRECIPITATION IS EXPECTED TO TURN TO ALL RAIN THERE IS
A POSSIBILITY THAT BROAD PASS MAY REMAIN ALL SNOW INTO SATURDAY
AND THIS WOULD PRODUCE A SIGNIFICANT SNOWFALL IN THAT AREA. AT
THIS TIME THAT DOES NOT LOOK LIKE IT WILL HAPPEN BUT IT STILL
CANNOT BE RULED OUT.

&&

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

A PRETTY NICE MORNING WILL GIVE WAY TO INCREASING CLOUD COVER AND
INCREASING RAIN CHANCES THROUGHOUT THE DAY. A STORM FORCE FRONT
OVER THE BERING SEA WILL RAPIDLY PUSH TOWARD SOUTHWEST ALASKA THIS
MORNING WHILE GRADUALLY WEAKENING. THE STRONGEST WIND GUSTS WILL
REMAIN OFFSHORE BUT WIND GUSTS IN THE RANGE OF 50 TO 60 MPH OVER
COASTAL LOCATIONS AND 40 TO 50 MPH OVER INLAND LOCATIONS ARE WELL
WITHIN THE REALM OF POSSIBILITY. THE FRONT WILL BRING SOME MODERATE
TO HEAVY RAIN ACROSS ALL OF SOUTHWEST ALASKA. HOWEVER...THE FRONT
SHOULD BE QUICK MOVING AND RAINFALL AMOUNTS SHOULD GENERALLY BE
LESS THAN ONE INCH WITH THE EXCEPTION OF THE ALASKA PENINSULA
WHERE UP TO 2 INCHES COULD BE SEEN. THE FRONT WILL EVENTUALLY
STALL NEAR THE ALEUTIAN RANGE AND KEEP SIGNIFICANT RAIN CHANCES
ALONG THE MOUNTAINS WHILE RAIN CHANCES GRADUALLY TAPER OFF LATE
FRIDAY MORNING AND FRIDAY AFTERNOON. THE UPPER LEVEL TROUGH AXIS
WILL SHIFT EASTWARD AND PUSH ANOTHER FRONT THROUGH FRIDAY EVENING
AND SATURDAY LEADING TO ANOTHER PERIOD OF DECENT RAINFALL. 850 MB
TEMPERATURES SHOULD CONTINUE TO WARM AS THE WARM FRONT APPROACHES
SO NO PRECIPITATION TYPE ISSUES ARE EXPECTED. DEEP LAYER SOUTHWESTERLY
FLOW WILL CONTINUE TO ADVECT WARMER AIR NORTHWARD TOWARD SOUTHWEST
ALASKA LEAVING THEM WITH ABOVE NORMAL TEMPERATURES.

&&

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

RAPID CYCLOGENESIS IN UNDERWAY OVER THE WESTERN BERING SEA AS A
TRIPLE POINT LOW RAPIDLY DEVELOPS IN THE EXIT REGION OF A 170 KT
JET. THIS WILL DRIVE A STORM FORCE FRONT ACROSS THE CENTRAL AND
EASTERN BERING SEA TODAY BEFORE MOVING INLAND TONIGHT. WIND GUSTS
UP TO 60 TO 70 MPH WILL BE OBSERVED OVER THE ALEUTIAN ISLANDS BUT
THE STRONGEST WIND GUSTS WILL BE TRAPPED JUST ABOVE THE SURFACE
DUE TO STRONG WARM AIR ADVECTION. 850 MB TEMPERATURES WILL BE
WARMING TO THE +4 TO +6 DEGREES CELSIUS AS THE WARM FRONT
OVERSPREADS THE BERING SEA. THIS WILL CREATE A WEAK SURFACE
INVERSION LEADING TO THE STRONGER WINDS BEING TRAPPED JUST OFF THE
SURFACE. IN ADDITION TO THE STRONG WINDS...HEAVY RAIN IS ALSO
LIKELY. THE RAIN SHOULD RAPIDLY PUSH EAST ALONG THE FRONTAL
BOUNDARY SO RAINFALL AMOUNTS WILL BE LIMITED A BIT...WITH MOST
LOCATIONS SEEING BETWEEN 0.5 INCHES AND 0.75 INCHES. FOLLOWING THE
SURGE OF WARMER AIR AHEAD OF THE FRONT...TEMPERATURES ALOFT WILL
ONCE AGAIN COOL LATE BY FRIDAY MORNING AND RAIN SHOWERS WILL ONCE
AGAIN BE SEEN ACROSS MUCH OF THE BERING SEA.

&&

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

BY SATURDAY MORNING MOIST SOUTHWESTERLY FLOW ALOFT WILL PREVAIL
ACROSS THE SOUTHERN HALF OF MAINLAND ALASKA BETWEEN AN UPPER LEVEL
TROUGH SWINGING FROM BRISTOL BAY INTO SOUTHWEST ALASKA AND A RIDGE
SHIFTING EAST INTO WESTERN CANADA. A SMALLER SCALE FRONTAL WAVE
WITH ACCOMPANYING 500 MB JET STREAK ROTATING THROUGH THE BROADER
TROUGH WILL LIFT NORTH UP COOK INLET AND INTO SOUTH CENTRAL ALASKA
SATURDAY MORNING. THE BROAD UPPER TROUGH WILL PROGRESS EAST INTO
SOUTH CENTRAL ALASKA SATURDAY AND THE WEAKEN RAPIDLY SATURDAY
NIGHT AS IT EXITS THE AREA. UPPER LEVEL RIDGING BRINGING DRIER
WEATHER WILL STRENGTHEN OVER WESTERN ALASKA SUNDAY THEN SHIFT EAST
TO BE CENTERED OVER MAINLAND ALASKA MONDAY.

A SPRAWLING UPPER LOW AND ASSOCIATED FRONTAL ZONE WILL MOVE INTO
THE BERING SEA ON SUNDAY...WITH THE ASSOCIATED FRONTAL ZONE MOVING
EAST ACROSS THE BERING AND APPROACHING THE WESTERN ALASKA COAST
MONDAY. THERE CONTINUES TO BE SOME DISCREPANCY WITH HOW MUCH THE
BERING TROUGH INTERACTS WITH A NORTH PACIFIC LOW SOUTH OF THE
ALASKA MAINLAND...AND HOW FAR EAST PRECIPITATION MOVES TUESDAY AND
WEDNESDAY. THE ECMWF AND GFS DIFFER RUN BY RUN WITH THIS
SCENARIO...WHICH KEEPS CONFIDENCE LOWER BY THE MIDDLE OF NEXT
WEEK. AS A RESULT...A WPC APPROACH WHICH FAVORS ENSEMBLE BLENDS
WAS CONTINUED...WHICH KEEPS THE CHANCE FOR RAIN ACROSS ALASKA
BEGINNING EARLY NEXT WEEK. NEAR NORMAL CONDITIONS ARE EXPECTED
THROUGH THE EXTENDED FORECAST PERIOD WITH NO MAJOR STORMS OR COLD
OUTBREAKS EXPECTED.

&&

.HYDROLOGY (FRIDAY AND SATURDAY)...

THE FRONTAL SYSTEM PUSHING INTO SOUTH CENTRAL ALASKA ON FRIDAY
WILL STALL OVER THE AREA FRIDAY NIGHT AND SATURDAY BRINGING A
SUBSTANTIAL STREAM OF MOISTURE UP FROM THE SOUTH-SOUTHWEST. THE
FLOW DIRECTION AND FRONTAL POSITION WILL FAVOR THE CHANNELING OF
MOISTURE UP COOK INLET AND INTO THE SUSITNA VALLEY WITH THE
HIGHEST PRECIPITATION ACCUMULATIONS ALONG THE ALASKA RANGE AND
TALKEETNA MOUNTAINS AS WELL AS ALONG THE SOUTHEAST SIDE OF THE
KENAI PENINSULA AND WESTERN PRINCE WILLIAM SOUND.

BETWEEN FRIDAY AND FRIDAY NIGHT...24-HOUR RAINFALL TOTALS WILL
RANGE BETWEEN AN INCH AND INCH AND A HALF WITH SOUTHERN AND
COASTAL AREAS MOST FAVORED FOR THE HIGHER AMOUNTS AND BETWEEN A
HALF AN INCH AND AN INCH FALLING IN THE SUSITNA VALLEY AND
ADJACENT MOUNTAINS. ON SATURDAY A FRONTAL WAVE LIFTING NORTH UP
COOK INLET WILL INCREASE RAINFALL RATES AND FOCUS THEM FURTHER
NORTH WITH THE 850 AND 700 MB WINDS CHANNELING MOISTURE UP THE
SUSITNA VALLEY. DURING THIS TIME PERIOD PRECIPITATION AMOUNTS
BETWEEN A HALF AND THREE QUARTERS OF AN INCH OF RAIN ARE EXPECTED
AT LOWER ELEVATIONS WITH AN ADDITIONAL ONE TO TWO INCHES ALONG
THE ALASKA RANGE AND TALKEETNA MOUNTAINS SURROUNDING THE SUSITNA
VALLEY WITH THE MAJORITY OF THAT RAIN FALLING DURING THE DAY ON
SATURDAY.

WITH RIVER FLOWS STILL EXPECTED TO REMAIN MODERATELY HIGH FROM
THE LAST RAIN EVENT AND SOME WET SNOW MELTING AT THE ONSET OF THE
WARMER RAIN...STREAMS ALONG THE SUSITNA VALLEY AND COMING OFF OF
THE SOUTHERN TALKEETNAS WILL BEAR CLOSE WATCHING. OF PARTICULAR
CONCERN WILL BE BASINS WITH A SOUTH-SOUTHWEST FACING ASPECT WHERE
OROGRAPHIC ENHANCEMENT RAINFALL WILL BE MAXIMIZED.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH SURF ADVISORY 155.
MARINE...STORM WARNING 170 172 173 174 179 180 181 185.
         GALE WARNING 155 160 165 171 175 176 177.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...JW
SOUTHCENTRAL ALASKA...EZ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MC
LONG TERM...JER/JA