Small Craft Advisory 169, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
308 PM AKST SUN NOV 6 2011

.DISCUSSION...

COMPUTER MODELS ARE CLOSE TO AGREEMENT ON THE TRACK OF THE NEXT
MAJOR STORM SYSTEM THAT WILL MOVE INTO THE BERING SEA ON TUESDAY.
THE GFS IS 5 MB DEEPER WITH THE FORECASTED SURFACE PRESSURE THAN
THE EUROPEAN MODEL. THE GFS HAS A 945 MB LOW WEST OF SAINT
LAWRENCE ISLAND BY TUESDAY EVENING. THE EUROPEAN AROUND 950 MB AND
THE TRACK IS MORE TO THE EAST THAN THE GFS. BOTH ARE IN AGREEMENT
ON STRONG SOUTH SOUTHEAST WINDS DEVELOPING LATE TUESDAY AFTERNOON
FOR MUCH OF THE WEST COAST AND LASTING INTO WEDNESDAY.

THIS DEVELOPING STORM WHICH CAME INTO VIEW AS IT MOVED OFF THE
COAST OF JAPAN LATE SATURDAY EVENING. IT IS FORECAST TO BE A 950
MILLIBAR LOW NEAR ATTU /AT THE WEST END OF THE ALEUTIAN ISLANDS/
ON TUESDAY MORNING...AND A 945 MILLIBAR LOW NEAR BERING STRAIT ON
WEDNESDAY MORNING.

THE NORTHWEST PACIFIC SATELLITE IMAGERY OVERNIGHT HAS SHOWN THIS
SYSTEM GATHERING STRENGTH AS WELL AS MOVING RAPIDLY EASTWARD...AT
A SPEED AROUND 50 MPH. THIS IMAGERY...SURFACE WEATHER
ANALYSES...AND THE GREAT CONSISTENCY OF THE COMPUTER WEATHER
FORECAST MODELS...ARE THE CRUCIAL INGREDIENTS THAT SUPPORT THE
FORECAST OF STORM FORCE WINDS AND THE POSSIBILITY OF MAJOR COASTAL
FLOODING ON THE NORTHWEST COAST TUESDAY AND WEDNESDAY.

THIS LOW IS REMARKABLY SIMILAR TO THE STORM THAT CAUSED MAJOR
COASTAL FLOODING ON THE NORTHWEST ALASKA COAST ON NOVEMBER 11 AND
12 IN 1974. THE ONLY DIFFERENCE OF ANY NOTE IS THAT THE 1974 STORM
CENTER CROSSED THE ALEUTIANS NEAR THE INTERNATIONAL DATE LINE.
THIS NOVEMBERS STORM IS DUE TO CROSS THE ALEUTIAN CHAIN AT ITS
WEST END ON TUESDAY MORNING. THIS NOVEMBERS STORM IS FORECAST TO
REACH BERING STRAIT WEDNESDAY MORNING. THE 1974 STORM ALSO ENDED
UP AT BERING STRAIT. IN A FEW WORDS...THE ORIGINS AND PATHS OF
THESE STORMS ARE SLIGHTLY DIFFERENT...BUT THEIR DESTINATIONS ARE
THE SAME.

THE OCEAN TIDES ALONG THE NORTHWEST ALASKA COAST THIS WEEK ARE AT
AVERAGE LEVELS. THE OCEAN TIDES AT THE TIME OF THE 1974 STORM WERE
AT MOST A FOOT OR TWO ABOVE THIS YEARS. HENCE...THIS IS A MINOR
FACTOR. IN THE 1974 STORM...THE WIND DRIVEN RISE IN SEA LEVEL WAS
CLOSE TO 10 FEET.

IN THE 1974 STORM THERE WAS CONSIDERABLE SEA ICE IN NORTON
SOUND. THE SOUTHEAST CHUKCHI SEA...FROM BERING STRAIT UP TO
BARROW INCLUDING KOTZEBUE SOUND...HAD EXTENSIVE ICE COVER DURING
THE 1974 STORM. THIS YEAR THERE IS ONLY A SMALL AREA OF SHORE ICE
IN EASTERN NORTON SOUND. ON THE CHUKCHI SEA COAST THERE IS ONLY A
NARROW STRETCH OF ICE...LESS THAN 10 MILES WIDE...FROM BERING
STRAIT TO POINT HOPE. KOTZEBUE SOUND IS 50 TO 70 PERCENT ICE
COVERED. ALL OF THIS MEANS IS THAT THERE WILL BE VERY LITTLE SHORE
ICE TO PROVIDE SOME PROTECTION TO THE COAST.

TTHE LATEST GFS MODEL FORECASTS INDICATE A SHARP CHANGE IN THE
WIND OVER NORTON SOUND ON WEDNESDAY MORNING...SHIFTING FROM
SOUTHEAST TUESDAY NIGHT TO SOUTHWEST WEDNESDAY MORNING. IF THE
OUTCOME ON WEDNESDAY FOLLOWS THIS FORECAST...THERE WOULD BE
ADDITIONAL COASTAL FLOODING ON THE YUKON DELTA AND IN EASTERN
NORTON SOUND.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4 /TUESDAY NOVEMBER 8 AND
WEDNESDAY NOVEMBER 9/...

STORM AND MAJOR COASTAL FLOODING POSSIBLE FROM CAPE DARBY TO NOME
AND POINTS WEST. ALONG THE BERING STRAIT...AND FROM BERING STRAIT
UP TO POINT HOPE STARTING TUESDAY NIGHT...AND CONTINUING THROUGH
WEDNESDAY. DUE TO THIS POTENTIAL COAST FLOOD WATCHES HAVE BEEN ISSUED
FOR ZONES 211, 213 ALONG THE BERING STRAIT COAST AND ZONE 207 FOR AREAS
NORTH OF CAPE KRUSENSTERN.

ALONG WITH THIS POTENTIAL, THERE WILL BE STRONG SOUTH SOUTHEAST
WINDS OF 45 TO 55 MPH WITH SNOW AND BLOWING SNOW. BLIZZARD WATCHES
HAVE BEEN ISSUED FOR ZONES 211, 210 AND 207. WINTER STORM WATCHES
FOR ZONE 213, 214 AND 212 FOR HEAVY SNOW POTENTIAL LATE TUESDAY
INTO WEDNESDAY.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
BLIZZARD WATCH FOR AKZ207-AKZ210-AKZ211.

COASTAL FLOOD WATCH FOR AKZ207-AKZ211-AKZ213.

WINTER STORM WATCH FOR AKZ212-AKZ213-AKZ214.

HEAVY FREEZING SPRAY WARNING FOR PKZ200-PKZ210-PKZ220-PKZ225-
PKZ230.

SMALL CRAFT ADVISORY FOR PKZ200-PKZ210-PKZ220-PKZ225.

BRISK WIND ADVISORY FOR PKZ245.
&&

JK NOV 11