Small Craft Advisory 988, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE ANCHORAGE AK
443 PM AKST THU DEC 11 2014

.ANALYSIS AND UPPER LEVELS...
THERE IS AN UPPER LEVEL LOW OVER THE NORTHERN GULF OF ALASKA WITH
A WEAK TROUGH STRETCHING NORTH-NORTHWEST INTO MAINLAND ALASKA.
THERE IS A WEAK UPPER LOW OVER THE NORTHWEST BERING SEA WITH WEAK
RIDGING OVER THE EASTERN BERING. A FAIRLY STRONG EASTWARD MOVING
UPPER LOW IS SOUTH OF THE EASTERN ALEUTIANS CENTERED NEAR 45N 170W
ANOTHER STRONG LOW IS NORTHEAST OF JAPAN AND MOVING TO THE WEST-
NORTHWEST. THE LAST TWO LOWS MENTIONED ARE ASSOCIATED WITH A
FAIRLY STRONG SUBTROPICAL JET.

&&

.MODEL DISCUSSION...
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT UNTIL AROUND 3 PM AKST SAT
AFTERNOON THEN THEY BEGIN TO DIVERGE ON THE SPEED/LOCATION OF VARIOUS
SURFACE LOWS. BETWEEN SAT AFTERNOON AND SUN AFTERNOON EACH MODEL
SEEMS TO BE HEADED IN A SLIGHTLY DIFFERENT DIRECTION WITH NO
CLUSTERING OF SOLUTIONS. THUS FORECAST CONFIDENCE IS NEAR TO ABOVE
NORMAL EARLY ON THEN A LITTLE BELOW NORMAL LATER ON.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2...FRIDAY
AND SATURDAY)...FOG CONTINUES TO BE THE BIG STORY FOR PARTS OF THE
ANCHORAGE BOWL WHILE MOST OTHER AREAS ARE ACTUALLY ENJOYING A
RELATIVELY QUIET WEATHER DAY. NOT MUCH CHANGE IS EXPECTED OVER THE
NEXT 24 HOURS AND THIS FOG COULD ACTUALLY HOLD ON ITS PART OF THE
BOWL UNTIL FRIDAY MORNING. ONE LOW ALONG THE PANHANDLE WILL
WEAKEN AS ANOTHER VERY WEAK LOW MOVES ACROSS THE KENAI PENINSULA
TOWARDS THE GULF. THEY WILL CONSOLIDATE OVER THE NORTHERN GULF AND
OPEN TO A BROAD AREA OF LOW PRESSURE JUST SOUTH OF PRINCE WILLIAM
SOUND ON FRIDAY. THIS WILL BRING SOME LIGHT RAIN AND SNOW SHOWERS
ACROSS PART OF THE GULF COAST AND EASTERN PRINCE WILLIAM SOUND. AT
THIS POINT IT DOES NOT LOOK LIKE MUCH IN THE WAY OF PRECIPITATION
WILL MAKE IT OVER THE MOUNTAINS. WE ARE JUST EXPECTING FLURRIES
INTO THE ANCHORAGE AND MAT-SU AREAS. A FEW MORE SNOW SHOWERS ARE
EXPECTED INTO FRIDAY NIGHT AS A WEAK UPPER WAVE SWINGS THROUGH
FROM THE NORTHWEST AND COULD HELP TO WRING OUT THE MOISTURE
WRAPPING AROUND FROM THE EAST. A MUCH STRONGER LOW WILL MOVE INTO
THE GULF THROUGH THE DAY ON SATURDAY. FORECAST MODELS ARE STILL
IRONING OUT THE DIFFERENCE IN THE EXACT LOW LOCATION AT THE
SURFACE BUT THIS CERTAINLY LOOKS TO BRING A HEALTHY SLUG OF
MOISTURE AND WARM AIR TO THE GULF COAST. THE FORECAST FOR INLAND
AREAS FROM THE KENAI PENINSULA THROUGH THE MAT-SU VALLEY WILL BE A
BIT MORE TRICKY. RIGHT NOW IT APPEARS THAT MOST OF THE MOISTURE
WILL MISS THIS AREA DUE TO SOME MODERATE CROSS-BARRIER FLOW.
HOWEVER IF THE LOW DOES MOVE FARTHER TO THE WEST AND CLOSER TO THE
COAST CROSS-BARRIER FLOW WOULD BE MUCH WEAKER. TWO OTHER PIECES
TO THE FORECAST ARE A FAIRLY STOUT UPPER LEVEL TROUGH IMPINGING ON
THE AREA FROM THE WEST LATE SATURDAY AND EXACTLY WHAT TYPE OF
PRECIPITATION WILL REACH THE GROUND WITH TEMPERATURES ONCE AGAIN
HOVERING NEAR FREEZING. FOR NOW IT DOES LOOK TO BE A BIG PRECIPITATION
MAKER FOR THE MAJOR POPULATION CENTERS BUT STAY TUNED TO THE FORECAST.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (FRIDAY AND SATURDAY)...AN
UPPER LEVEL WEAK SHORTWAVE WILL PUSH THROUGH THE SOUTHWEST ALASKA
REGION BY FRIDAY MORNING. THIS WILL RESULT IN SCATTERED SNOW SHOWERS
THROUGH THE AREA. BY LATE FRIDAY EVENING A SECOND STRONGER SHORTWAVE
WILL PUSH INTO THE REGION. THIS WILL BRING NUMEROUS SNOW SHOWERS
THROUGHOUT THE SOUTHWEST ALASKA REGION INTO SATURDAY MORNING
BEFORE TAPERING OFF BY MIDDAY. THE WINDS WILL BE NORTHWESTERLY
BEFORE SHIFTING TO ONSHORE FLOW BY SATURDAY. THE SOUTHWEST ALASKA
INTERIOR LOCATIONS WILL HAVE LIGHT WINDS AND THIS WILL INCREASE
THE CHANCES FOR NOCTURNAL PATCHY FOG THROUGH SATURDAY MORNING.
ALONG THE BRISTOL BAY COASTLINE THEY WILL HAVE ONSHORE FLOW
RESULTING IN AREAS OF FOG AND STRATUS THROUGH SATURDAY MORNING
BEFORE DISSIPATING BY MIDDAY. THE WINDS ALONG THE KUSKOKWIM BAY
AND BRISTOL BAY WILL BE CLOSE TO SOUTHERLY GALE FORCE BY SATURDAY
EVENING WITH THE APPROACHING WEATHER FRONT TRACKING INTO THE
EASTERN BERING SEA.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (FRIDAY AND SATURDAY)...
THE WESTERN ALEUTIANS WILL HAVE SOUTHERLY GALE FORCE WINDS WITH A
WEATHER FRONT PUSHING THROUGH THE ALEUTIANS ASSOCIATED WITH A
GALE FORCE LOW OVER THE SOUTHERN KAMCHATKA PENINSULA BY FRIDAY.
BY SATURDAY THE WEATHER FRONT WILL BE MOVING THROUGH THE PRIBILOF
ISLANDS AND THE UNALASKA AREA WITH A SECONDARY GALE FORCE LOW
FORMING OVER THE WESTERN BERING SEA. THIS WILL BRING RAIN ALONG
THE ALEUTIANS AND RAIN/SNOW THROUGH THE CENTRAL BERING SEA THROUGH
THE PRIBILOF ISLANDS AS THE FRONT MOVES THROUGH. THE WESTERN
ALEUTIANS WILL BE ON THE BACK SIDE OF THE LOW BY SATURDAY RESULTING
IN WESTERLY WINDS WITH SCATTERED SHOWERY PRECIPITATION. BY LATE
SATURDAY EVENING A GALE FORCE LOW WILL TRACK JUST SOUTH OF
UNALASKA BRINGING SOUTHERLY GALE FORCE WINDS TO THE EASTERN
ALEUTIANS WITH WIDESPREAD RAIN GOING INTO LATE SATURDAY NIGHT.
THE NORTHERN BERING SEA WILL CONTINUE TO HAVE NORTHEAST GALE FORCE
WINDS WITH THE GALE FORCE LOW POSITIONED WEST OF THE PRIBILOF
ISLANDS AS IT CONTINUES TO TRACK TOWARDS THE SAINT MATTHEW ISLAND
BY LATE SATURDAY NIGHT.

&&

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

MODELS ARE IN AGREEMENT THAT SAT NIGHT THROUGH TUE A BROAD
NEGATIVELY TILTED UPPER LEVEL TROUGH WILL EXTEND FROM
KAMCHATKA...ACROSS THE AKPEN AND PACIFIC TO CALIFORNIA. THE
PATTERN THEN BECOMES PROGRESSIVE AND A SERIES OF TROUGHS AND
RIDGES WILL THEN MOVE ACROSS THE REGION THROUGH THE END OF THE
WEEK. AT THE SURFACE THIS TRANSLATES TO A BROAD AREA OF LOW
PRESSURE CENTERED OVER THE AKPEN THAT MIGRATES TO THE GULF ON THU.
A FRONT WILL MOVE ACROSS THE GULF MON THROUGH WED...AND A TROUGH
WILL AFFECT THE BERING AND ALEUTIANS DURING THE SAME PERIOD. A
STRONG FRONT WILL THEN MOVE INTO THE WESTERN ALEUTIANS THU. THE
FORECAST RELIES HEAVILY ON A WPC SOLUTION...WITH WIND FIELD
ENHANCED BY A BLEND TO THE 12Z EC.

RAIN AND SNOW SHOWERS WILL AFFECT THE BERING...ALEUTIANS...AND
SOUTHWEST AK THROUGH THE END OF THE NEXT WEEK. RAIN WILL AFFECT
THE GULF COAST WITH SNOW SHOWERS INTO SOUTH CENTRAL. COLD AIR AT
THE SURFACE IN PORTIONS OF SOUTH CENTRAL MAY RESULT IN SOME
FREEZING RAIN ACTIVITY UNTIL WARM AIR SCOURS OUT COLD POCKETS
DURING THE COURSE OF NEXT WEEK.

&&

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

&&

SYNOPSIS AND MODEL DISCUSSION...BL/SAM
SOUTHCENTRAL ALASKA...MO
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PD
LONG TERM...DS