Small Craft Advisory 947, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE ANCHORAGE AK
457 AM AKST FRI NOV 28 2014

.ANALYSIS AND UPPER LEVELS...
MAINLY CLEAR SKIES PREVAIL ACROSS SOUTHCENTRAL ALASKA THIS MORNING
BENEATH AN UPPER LEVEL RIDGE...WITH THE EXCEPTION OF A FEW
PERSISTENT AREAS OF LOW STRATUS AND FOG FROM THE ANCHORAGE BOWL
AND MATANUSKA VALLEY INTO THE COPPER RIVER BASIN AS MOISTURE
REMAINS TRAPPED BENEATH A LOW LEVEL INVERSION. A FEW MID AND HIGH
LEVEL CLOUDS ARE BEGINNING TO WORK THEIR WAY INTO THE COOK INLET
REGION AND SUSITNA VALLEY AS THE RIDGE AXIS SHIFTS GRADUALLY
EASTWARD. A WEAKENING FRONT IS SPREADING A MIX OF RAIN AND SNOW
SHOWERS OVER PORTIONS OF BRISTOL BAY AND THE LOWER KUSKOKWIM
VALLEY AS IT PUSHES INLAND FROM THE EASTERN BERING SEA. STRONG
WINDS HAVE GENERALLY SUBSIDED ACROSS THE BERING AS A LOW PRESSURE
SYSTEM TRACKS NORTHWARD TOWARDS THE BERING STRAIT...BUT WIDESPREAD
SHOWERS REMAIN OVER THE REGION BENEATH CYCLONIC FLOW ALOFT.

&&

.MODEL DISCUSSION...
FORECAST CONFIDENCE REMAINS ABOVE AVERAGE IN THE SHORT TERM AS
MODELS SHOW GOOD AGREEMENT WITH RESPECT TO SYNOPTIC FEATURES
THROUGH THE WEEKEND. PREFERRED THE GFS OVER THE WESTERN PART OF
THE DOMAIN AND CONTINUED TO UTILIZE HIGHER RESOLUTION MODELS
CLOSER TO THE GULF FOR THEIR HANDLING OF SMALL SCALE FEATURES.

&&

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

WITH THE UPPER LEVEL RIDGE MOVING TO THE EAST THERE ARE SOME
CLOUDS MOVING INTO SOUTHCENTRAL FROM WEST TO EAST TODAY. MOST OF
THE AREA WILL REMAIN WITHOUT PRECIPITATION TODAY EXCEPT FOR KODIAK
WHICH WILL BE IN THE RAIN. THE INCREASING CLOUDINESS WILL HELP TO
REDUCE THE FOG IN THE COOK INLET REGION TODAY BUT A STRONG
INVERSION TO AROUND 1300 FT...AS SEEN ON THE ANCHORAGE RAOB THIS
MORNING...WILL KEEP SOME AREAS OF FOG AND STRATUS AROUND THROUGH
THE MORNING. THE COPPER RIVER BASIN REMAINS ENTRENCHED IN THE
STRATUS AND MAY HAVE A DIFFICULT TIME BREAKING OUT TODAY. THE
INCREASING MID AND HIGH LEVEL CLOUDS MAY HELP TO BRING SOME MORE
MIXING THROUGH THE ATMOSPHERE AND IMPROVE CONDITIONS THIS
AFTERNOON.

A STRONG SHORT WAVE WILL MOVE THROUGH SOUTHCENTRAL ALASKA SATURDAY
AND THIS IS WHAT WILL BRING IN THE SNOWFALL LATE TONIGHT INTO
SATURDAY AFTERNOON. THIS TROUGH WILL MOVE THROUGH THE AREA RATHER
QUICKLY AS ANOTHER UPPER LEVEL RIDGE MOVES INTO THE AREA LATE
SATURDAY NIGHT INTO SUNDAY. THIS WILL LIMIT THE SNOWFALL TO JUST A
FEW INCHES FOR MOST LOCATIONS ACROSS SOUTHCENTRAL.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
SURFACE RIDGING ACROSS THE SOUTHWEST MAINLAND BREAKS DOWN TODAY
AS A COMBINATION OF WEAK TROUGHING WORKS INLAND FROM THE KUSKOKWIM
DELTA AND ANOTHER SURFACE LOW MOVES A FRONT UP FROM THE NORTH
PACIFIC. ISOLATED TO SCATTERED SNOW SHOWERS WILL BECOME NUMEROUS
IN THE AFTERNOON ACROSS THE KUSKOKWIM AND BRISTOL BAY. A WARMER
AIR MASS ALONG AND SOUTH OF KING SALMON WILL SUPPORT
PRECIPITATION TO FALL AS RAIN...WITH SNOW MIXED AT TIMES.
PRECIPITATION WILL DIMINISH ON SATURDAY FROM WEST TO EAST AS
RIDGING BUILDS BACK INTO THE SOUTHWEST FROM THE BERING.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
LOW PRESSURE OVER THE NORTHERN BERING PUSHES A SHORTWAVE OVER THE
EASTERN BERING TODAY. PRECIPITATION DEVELOPS ALONG THIS WAVE AS RAIN
WITH SNOW MIXED NORTH OF THE PRIBILOF ISLANDS. THE NEXT
SIGNIFICANT FRONT MOVES INTO THE WESTERN ALEUTIANS BY SATURDAY
MORNING BRINGING HEAVY RAIN AND GUSTY GALE WINDS. THE LOW CENTER
DRIVING THE FRONT MOVES ACROSS THE CENTRAL ALEUTIANS LATE SATURDAY
PUSHING THE FRONTAL BOUNDARY THROUGH MUCH OF THE BERING BY
SATURDAY NIGHT.

&&

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

BY SUNDAY AN UPPER RIDGE WILL BUILD OVER THE EASTERN BERING WHILE
A TROUGH WITH EMBEDDED CUT-OFF LOW DIGS INTO THE WESTERN BERING.
AS THE RIDGE MOVES TO THE ALCAN BY TUE THE CUT-OFF WILL CROSS THE
BERING AND THEN THE AKPEN INTO THE NORTH PACIFIC ON WED. AN UPPER
LOW FROM NORTHERN CANADA WILL ROTATE AROUND THE REMAINS OF THE
RIDGE AND ARRIVE NEAR THE BERING STRAIT EARLY ON THU. AT THE
SURFACE...A LOW MOVING ACROSS THE ALEUTIANS WILL BE FORCED TO
PINWHEEL IN THE WESTERN BERING ON MON BEFORE RECROSSING THE
ALEUTIANS NEAR DUTCH HARBOR LATE ON TUE AND THEN MOVING INTO THE
NORTH PACIFIC ON WED. A LOW WILL MOVE INTO THE NORTHERN BERING ON
THU. A WARM FRONT ASSOCIATED WITH THE ORIGINAL BERING LOW WILL
CROSS SOUTHWEST AK ON SUN AND THEN SOUTHCENTRAL SUNDAY NIGHT
THROUGH MON. THE TRAILING COLD FRONT WILL SWEEP ACROSS THE
ALEUTIANS SUN AND MON. FINALLY THE OCCLUDED FRONT WILL AFFECT
SOUTHWEST AK AND SOUTHCENTRAL TUE AND WED.

FORECAST CONFIDENCE IS FAIRLY HIGH SUN THROUGH TUE...AND THEN
BECOMES LESS SO AS MODELS BEGIN TO DIVERGE WITH POSITIONS OF THE
LOWS BOTH IN THE NORTHERN BERING AND SOUTH OF THE AKPEN. WPC WAS
USED AS A GOOD AVERAGE POSITION OF FEATURES THROUGH THU. THIS
SOLUTION BRINGS WIND AND RAIN TO THE BERING AND ALEUTIANS ON THE
EASTERN FLANK OF THE LOW THROUGH AT LEAST TUE...WITH WIND...AND
RAIN CHANGING TO SNOW SHOWERS ON THE WESTERN FLANK THROUGH THU.
SOUTHWEST AND SOUTHCENTRAL WILL HAVE RAIN AND SNOW SUN NIGHT
THROUGH WED...WITH RAIN ON THE COAST AND SNOW SHOWERS INLAND ON
THU.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...173 174 175 176 177 178.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...CB
SOUTHCENTRAL ALASKA...EZ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
LONG TERM...DS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1132 AM AKST FRI NOV 28 2014

AKZ121-292045-
WESTERN KENAI PENINSULA-
INCLUDING THE CITIES OF...KENAI...SOLDOTNA...HOMER...
COOPER LANDING
1132 AM AKST FRI NOV 28 2014

...HIGH WATER ON THE KENAI RIVER...

WATER LEVEL ON THE UPPER KENAI RIVER AT COOPER LANDING HAS FALLEN
STEADILY OVER THE PAST FIVE DAYS WHILE THE KENAI RIVER LEVEL AT
THE OUTLET OF SKILAK LAKE HAS CONTINUED TO RISE. THIS MAY INDICATE
SKILAK GLACIER DAM LAKE IS RELEASING. SKILAK GLACIER DAM LAKE LAST
RELEASED IN SEPTEMBER 2013 THEREFORE THE VOLUME OF THE LAKE SHOULD
BE RELATIVELY SMALL AS COMPARED TO PREVIOUS RELEASES. IF THE
GLACIER DAM LAKE IS RELEASING THE KENAI RIVER COULD POTENTIALLY
RISE ANOTHER COUPLE OF FEET DEPENDING ON LOCATION BETWEEN THE
SKILAK LAKE OUTLET AND THE MOUTH OVER THE NEXT SEVERAL DAYS.

LIMITED ICE COVER IS BEING REPORTED ON THE LOWER KENAI RIVER WHICH
SHOULD REDUCE THE THREAT OF ICE JAM AND ICE RELATED IMPACTS DURING THIS
EVENT.

EXPECTED IMPACTS:
RESIDENTS ALONG THE RIVER...PARTICULARLY IN THE KENAI KEYS AND
BIG EDDY AREA...SHOULD BE AWARE THAT KENAI RIVER LEVELS ARE
RISING AND MAY CONTINUE TO RISE OVER THE NEXT SEVERAL DAYS.