Small Craft Advisory 131, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
600 AM AKDT TUE OCT 9 2012

.DISCUSSION...
COLDER AIR FROM THE ARCTIC IS CONTINUING TO FLOW DOWN OVER THE
REALM...AND IS EXPECTED TO SETTLE IN FOR THE NEXT 7 TO 10 DAYS.
COLDER AND LARGELY CLEAR WEATHER IS EXPECTED TO COME WITH THIS.
THE EXCEPTION TO THIS WILL BE THE ARCTIC. GIVEN A 400 TO 500 MILE
STRETCH OF OPEN WATER NORTH OF THE ALASKAN ARCTIC COAST...MOSTLY
CLOUDY SKIES AND SNOW SHOWERS SHOULD PREVAIL THERE FOR SOME TIME.

RIVERS IN NORTHERN ALASKA ARE WELL WITHIN THEIR BANKS AND ARE
GENERALLY LEVEL OR GRADUALLY DECLINING. FREEZEUP IS IN PROGRESS IN
NORTHERN INTERIOR RIVERS.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...THURSDAY AND FRIDAY...

SURF WILL DEVELOP ON THE NORTHERN SEWARD PENINSULA COAST FROM
CAPE KRUSENSTERN TO BERING STRAIT THURSDAY NIGHT AND FRIDAY AFTER
A STRONG COLD FRONT MOVES FROM THE CHUKCHI SEA TO THE NORTHERN
BERING SEA THURSDAY NIGHT. THE AREA INCLUDES SHISHMAREF.

THE WINDS OVER THE CHUKCHI SEA WILL BE 20 TO 35 MPH. THIS WIND
FLOW WILL BE FROM THE NORTHWEST...OVER AN ICE FREE FETCH OF 500
MILES. THIS IS AN UNUSUALLY LONG FETCH FOR THE CHUKCHI SEA. THE
INFLUX OF COLD AIR OVER THE RELATIVELY WARM OPEN WATER WILL
RESULT IN AN UNSTABLE AIR MASS...WITH A CONSIDERABLY GREATER GUST
FACTOR THAN WOULD COME WITH AN INFLOW OF WARM AIR.

THE UPSHOT IS EXPECTED TO BE A FULLY DEVELOPED SEA IN THE FETCH. A
FULLY DEVELOPED SEA IS A COMBINATION OF WAVES AND SWELL THAT REACH
THE MAXIMUM POSSIBLE HEIGHT FOR THE SPEED OF THE WIND. IN THIS
CASE...WITH A WIND OF 25 MPH OVER A 500 MILE FETCH OVER A 36 HOUR
SPAN OF TIME...THE HEIGHT OF WAVES IN A FULLY DEVELOPED SEA WOULD
BE BETWEEN 15 AND 20 FEET IN THE OPEN OCEAN. SUCH INCOMING WAVES
LOSE ENERGY AS THEY REACH RELATIVELY SHALLOW WATER NEAR SHORE. THE
SURF THEN COMING ASHORE IN THIS CASE WOULD BE SOMETHING FROM 5 TO
10 FEET HIGH...ENOUGH TO CAUSE SIGNIFICANT BEACH EROSION.

THE WIND FLOW PATTERN IN THIS CASE WILL NOT BRING UP TIDES ABOVE
NORMAL LEVELS. THIS IS TO SAY THAT A STORM SURGE...A WIND INDUCED
RISE IN SEA LEVEL ABOVE NORMAL...IS NOT EXPECTED TO BE A PROBLEM
HERE. IF THE WINDS OVER THE CHUKCHI SEA DEVELOP AS EXPECTED...THE
PROBLEM WOULD BE BEACH EROSION.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY FOR PKZ200-PKZ210-PKZ235-PKZ240-PKZ245.

GALE WARNING FOR PKZ210.
&&

TF OCT 12

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
609 AM AKDT TUE OCT 9 2012

AKZ222-091615-
MIDDLE TANANA VALLEY-
INCLUDING...FAIRBANKS...FORT WAINWRIGHT...EIELSON AFB...ESTER...
NORTH POLE...MOOSE CREEK...TWO RIVERS...FOX...CHATANIKA...
CHENA HOT SPRINGS...SOURDOUGH CAMP
609 AM AKDT TUE OCT 9 2012

...SLIPPERY ROADS THIS MORNING...

TEMPERATURES ARE NOW JUST BELOW FREEZING AND ARE CAUSING ICY
SPOTS ON THE WET SIDEWALKS AND ROADS THIS MORNING IN THE FAIRBANKS AREA.
BRIDGES ARE ESPECIALLY SLIPPERY. MOTORIST SHOULD USE CAUTION.

TEMPERATURES ARE EXPECTED TO RISE ABOVE FREEZING BY LATE MORNING.