Small Craft Advisory 57, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKST SAT JAN 18 2014

.ANALYSIS AND UPPER LEVELS...THE LARGE LOW THAT MOVES THROUGH THE
AREA YESTERDAY IS NOW CENTERED IN THE NORTHERN BERING SEA NEAR ST
MATTHEW ISLAND. THIS LOW WILL DRIFT WESTWARD AND WEAKEN OVER THE NEXT
TWO DAYS. ANOTHER FRONT ASSOCIATED WITH THIS LOW IS PUSHING ACROSS
THE KUSKOKWIM VALLEY THROUGH THE COPPER RIVER BASIN TODAY BRINGING
MORE RAIN SHOWERS TO SOUTH CENTRAL ALASKA.

THE UPPER LEVEL RIDGE THAT HAS BEEN HOLDING STRONG OVER SOUTHEAST
ALASKA WAS FLATTENED SOME AS THE STRONG FRONT MOVES THROUGH SOUTH
CENTRAL ALASKA YESTERDAY. THAT RIDGE....WHICH IS THE NORTHERN PART OF
THE LARGE RIDGE OVER THE WEST COAST OF NORTH AMERICA...IS ONCE AGAIN
AMPLIFYING IN THE SAME LOCATION OVER SOUTHEAST ALASKA AND ALONG THE
ALCAN BORDER. THIS WILL SEND THE NEXT LOW...WHICH IS CAN BE SEEN ON
SATELLITE IMAGERY CENTERED NEAR 45N 160W...ALONG A SIMILAR TRACK AS
THE ONE YESTERDAY. THE BIG DIFFERENCE WITH THESE TWO LOWS IS THAT
YESTERDAYS LOW WAS STRONGER AND STILL INTENSIFYING AS IT MOVED INTO
THE BERING SEA WHERE THE ONE TOMORROW WILL BE WEAKENING AND NOT AS
STRONG AS IT MOVES TO THE EASTERN BERING SEA.

.MODEL DISCUSSION...MODELS ARE DOING WELL WITH THE OVERALL PATTERN
THROUGH THE MIDDLE OF NEXT WEEK. THE LARGE LOW THAT IS WELL SOUTH OF
THE ALASKA PENINSULA WILL MOVE ACROSS THE PENINSULA SUNDAY NIGHT AND
INTO THE EASTERN BERING SEA. THE MODELS DIVERGE A BIT ON TUESDAY WHEN
THE GFS TAKES A MORE EASTERLY TRACK ALONG THE KUSKOKWIM DELTA COAST
WHILE THE NAM AND ECMWF BRING IT WEST OF ST MATTHEW ISLAND. GIVE THE
UPPER LEVEL PATTERN THE FARTHER WEST TRACK OF THE NAM AND ECMWF LOOKS
MORE REASONABLE THAN THE GFS SOLUTION.

.SHORT TERM FORECAST...
SOUTH CENTRAL...SOUTH TO SOUTHWEST FLOW ALOFT WILL BRING IN COLDER
TEMPERATURES AND A FEW SNOW SHOWERS IN THE EVENING BEFORE THE NEXT
LOW STARTS TO IMPACT THE AREA. THIS NEXT SYSTEM WILL BRING RAIN TO
KODIAK ISLAND BEGINNING TOMORROW MORNING WHICH WILL PERSIST ON AND
OFF FOR A FEW DAYS. THE HEAVIEST RAINFALL SHOULD OCCUR FROM SUNDAY
INTO MONDAY BUT SHOULD NOT BE AS INTENSE AS THE SYSTEM FROM FRIDAY
NIGHT. HOWEVER THEY IS A CHANCE THERE COULD BE ADDITIONAL MUDSLIDES
EVEN IN LESSER AMOUNTS OF RAINFALL DUE TO THE PREVIOUS HEAVY RAINS ON
KODIAK ISLAND.
AS THIS SYSTEM MOVES NORTHWARD INTO SOUTH CENTRAL ALASKA THE PRESSURE
GRADIENT WILL TIGHTEN UP AGAIN AND BRING ANOTHER CHINOOK TO THE AREA
SUNDAY NIGHT...BUT NOT AS STRONG AS THE ONE YESTERDAY.

SOUTHWEST...SNOW SHOWERS WILL PERSIST THROUGH THE NIGHT AS COLDER AIR
RETURNS IN THE SOUTHWEST FLOW ALOFT. THE NEXT LOW WILL MOVE INTO THE
EASTERN BERING SEA ON MONDAY AND BRING MORE RAIN AND WIND TO THE
BRISTOL BAY AREA AND KUSKOKWIM DELTA. THE KUSKOKWIM VALLEY HAS A SHOT
AT SOME FREEZING RAIN MONDAY BEFORE TEMPERATURES WARM UP ABOVE
FREEZING AT THE LOWER LEVELS. AS THIS LOW BEGINS TO ELONGATE IN THE
BERING SEA THE PRIBILOF ISLANDS WILL GET INTO GUSTY NORTHWEST WINDS
AND SNOW...WHICH WILL LIKELY BRING SOME LIMITED VISIBILITIES DUE TO
THE BLOWING SNOW SUNDAY NIGHT INTO MONDAY.

.LONG TERM FORECAST...THE UPPER LEVEL PATTERN DOES NOT CHANGE MUCH
OVER THE COURSE OF NEXT WEEK WHICH WILL LEAD TO VERY SIMILAR
CONDITIONS AS THE PAST FEW DAYS. TEMPERATURES WILL BE WELL ABOVE
NORMAL WITH PERIODS OF WIND AND PRECIPITATION AS THE LOWS MOVE
THROUGH THE AREA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 119 120 125 130 131 136 137 139
         STORM 132 138
FIRE WEATHER...NONE.

JAN 14

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ANCHORAGE AK
340 PM AKST SAT JAN 18 2014

AKZ101-111-121-125-145-191400-

...ELEVATED WATER LEVELS FOR SOME LOW LYING AREAS OF ANCHORAGE AND
REFREEZING OF EXPOSED SURFACES ACROSS SOUTHCENTRAL ALASKA...

RAIN HAS CONTINUED OVER THE ANCHORAGE AREA AS WEATHER DISTURBANCES
SWING THROUGH THE REGION. THIS COUPLED WITH HIGH FREEZING LEVELS
SINCE EARLY FRIDAY HAS ALLOWED FOR CONSIDERABLE RUNOFF AND SNOW MELT
RESULTING IN SOME LOCALLY HIGH WATER LEVELS ACROSS LOW LYING AREAS.
EXPECT THESE ELEVATED LEVELS TO CONTINUE INTO TONIGHT...WITH THE MAIN
IMPACTS BEING MINOR FLOODING FOR BIKE PATHS AND TRAILS AROUND CHESTER
AND CAMPBELL CREEKS.

ACROSS SOUTHCENTRAL...FREEZING LEVELS WILL BE FALLING OVERNIGHT AS
WILL AREA TEMPERATURES...WITH REFREEZING OF PONDED AREAS AND WET
SURFACES LIKELY BY EARLY SUNDAY MORNING.

JAM