Small Craft Advisory 106, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
350 AM AKST MON FEB 3 2014

.ANALYSIS AND UPPER LEVELS...

THE LARGE SCALE SYNOPTIC PATTERN FEATURES A REX BLOCK CONFIGURATION
OVER THE REGION WITH WITH A CLOSED HIGH OVER NORTHERN ALASKA AND A
BROAD TROUGH OVER THE NORTH PACIFIC. A DEEP AND STRONG TROUGH EXISTS
OVER EASTERN RUSSIA...WITH STRONG DISTURBANCES WRAPPING AROUND THE
PERIPHERY OF THIS FEATURE. HIGHLY AMPLIFIED SOUTHERLY FLOW EXISTS
OVER THE WESTERN BERING SEA...WITH THE FIRST IN A SERIES OF STRONG
RIDGE RIDING WAVES CURRENTLY TRACKING NORTH OF WRANGEL ISLAND AND
EASTERN SIBERIA. UPPER AIR FLOW OVER THE BERING SEA AND ALASKA
REMAINS RELATIVELY WEAK AS THE PERSISTENT BACKGROUND HIGH PRESSURE
FIELD ALOFT REMAINS DOMINANT. WATER VAPOR SATELLITE IMAGERY REVEALS A
WEAK COUPLET OF UPPER LEVEL ANOMALIES OVER CENTRAL ALASKA...AND
ANOTHER CURRENTLY TRACKING INTO THE BERING SEA OVER NUNIVAK ISLAND.
ANOTHER SHEARED UPPER LEVEL SHORTWAVE OVER THE ALASKA PENINSULA IS
LIFTING NORTH INTO BRISTOL BAY...WITH A LOW LEVEL WARM FRONT
FOLLOWING ON ITS HEELS. WITH BROAD LOW PRESSURE SLOWLY TRACKING NORTH
INTO THE SOUTHERN BERING ASSOCIATED WITH THE NPAC TROUGH...AND A
STOUT 1045 HIGH OVER THE YUKON AND NORTHERN ALASKA...A GENERAL
NORTHERLY OFFSHORE FLOW PATTERN WILL PERSIST THROUGH TONIGHT. THE
GENERAL WEAK FLOW PATTERN OVER ALASKA WILL PERSIST THROUGH MOST OF
THE WEEK BEFORE A LARGE SHIFT IN THE PATTERN OVER ALASKA OCCURS LATE
IN THE WEEK (SEE EXTENDED DISCUSSION).

.MODEL DISCUSSION...

THE SUITE OF NUMERICAL GUIDANCE IS IN EXCELLENT AGREEMENT THROUGH THE
END OF THE WEEK AND INTO NEXT WEEK. EVEN WITH THE SMALLER SCALE
SHORTWAVE FEATURES THEY LARGELY REMAIN IN EXCELLENT AGREEMENT INTO
THE WEEKEND. FORECAST CONFIDENCE IS HIGH THROUGH THE WEEKEND.

.SHORT TERM FORECAST...

SOUTHCENTRAL...
LARGELY QUIESCENT WEATHER WILL CONTINUE TO DOMINATE AS WEAK HIGH
PRESSURE REMAINS OVER THE REGION. DRY NORTHEAST WINDS WILL LARGELY
KEEP FOG AND LOW CLOUDS AT BAY TODAY. TEMPERATURES WILL REMAIN
SLIGHTLY BELOW AVERAGE OVER THE COPPER BASIN AND PORTIONS OF PRINCE
WILLIAM SOUND...WITH GENERALLY AVERAGE TEMPERATURES ELSEWHERE. WINDS
WILL REMAIN BREEZY FROM THE SOUTHEAST ALONG TURNAGAIN ARM AND ALONG
THE ANCHORAGE HILLSIDE...AS WELL AS NORTH INTO THE MATANUSKA
VALLEY...BEFORE HIGH PRESSURE BUILDS IN TUESDAY NIGHT. KODIAK ISLAND
WILL SEE PERIODS OF RAIN AND MIXED SNOW THROUGH MIDWEEK AS THE FRONT
STALLS OVER THE AREA. OTHERWISE...DRY CONDITIONS WILL DOMINATE
SOUTHCENTRAL THROUGH THURSDAY.

SOUTHWEST...
A WEAK WARM FRONT WILL PUSH INTO SOUTHWEST TODAY...WITH RAIN AND SNOW
SHOWERS LARGELY IMPACTING COASTAL LOCATIONS AND THE SOUTHERN ALASKA
PENINSULA. OTHERWISE...EAST TO NORTHEAST WINDS WILL KEEP MOST
INTERIOR LOCATIONS LARGELY DRY AND FOG FREE. SOUTHEAST WINDS WILL
INCREASE TODAY AND TONIGHT AS THE FRONT TRACKS NORTHEAST...ESPECIALLY
NEAR THE ALASKA/ALEUTIAN RANGES AND ALONG THE COAST. SHOWERS WILL
CONTINUE TO BE A THREAT ACROSS THE BRISTOL BAY COAST INTO WEDNESDAY
BEFORE THE REGION DRIES OUT.

BERING SEA/ALEUTIANS/WESTERN ALASKA PENINSULA...
A LOW OVER THE NORTH PACIFIC WILL SLOWLY TRACK NORTH TODAY...WITH AN
ASSOCIATED WARM FRONT TRACKING OVER THE ALASKA PENINSULA. RAIN AND
RAIN SHOWERS WILL IMPACT THE PENINSULA...WITH RAIN AND SNOW SHOWERS
OVER DUTCH HARBOR...TRANSITIONING TO ALL RAIN SHOWERS ON TUESDAY.
OTHERWISE...HIGH PRESSURE WILL BUILD IN WEDNESDAY...WITH RATHER
QUIESCENT WEATHER LASTING THROUGH THE REMAINDER OF THE WEEK.

.LONG TERM FORECAST...

A DRAMATIC PATTERN SHIFT WILL COMMENCE LATE WEEK AS A LARGE BLOCKING
HIGH RETROGRADES WEST OVER THE BERING SEA...AND A POWERFUL NORTHERLY
JET MAX TRACKS FROM THE ARCTIC CIRCLE INTO THE GULF OF ALASKA. THE
EXPECTED TRACK OF THIS STRONG DISTURBANCE WILL LIKELY MEAN MOST OF
SOUTHWEST ALASKA REMAINS COMPLETELY DRY FRIDAY THROUGH THE
WEEKEND...WITH THE BEST CHANCE FOR SNOW ACROSS LOCATIONS EAST OF THE
ALASKA/ALEUTIAN RANGES. RIGHT NOW ANY SNOW THREATS WOULD LIKELY BE
QUICK HITTING AND ON THE LIGHTER SIDE...ALTHOUGH THE DETAILS STILL
REMAIN SOMEWHAT UNCERTAIN. THE MUCH BIGGER SENSIBLE WEATHER IMPACTS
WILL BE SUBSTANTIALLY WINDIER CONDITIONS FRIDAY INTO SATURDAY AS A
1050 MB HIGH FORMS OVER THE NORTH SLOPE...AND A 990-995 MB LOW FORMS
IN THE GULF. CHANNELED GAP WINDS WILL RAMP UP ACROSS ALL FAVORED
MOUNTAIN LOCATIONS...ESPECIALLY THE MATANUSKA VALLEY WHERE WINDS MAY
BECOME QUITE STRONG....AND FOR A RATHER PROLONGED PERIOD OF TIME.
MARGINALLY STRONG GAP WINDS WILL FORM ACROSS PRINCE WILLIAM SOUND AS
WELL...WITH STRONG NORTHEAST OUTFLOW WINDS DEVELOPING FROM COOK INLET
WESTWARD. THEREAFTER...THERE IS A STRONG SIGNAL ACROSS THE VARIOUS
GLOBAL MODELING ENSEMBLES AND DETERMINISTIC MODELS THAT A DEEP TROUGH
FORMS AND PERSISTS OVER ALASKA...WITH A RETROGRADING AND WEAKENING
BERING HIGH. SHOULD THIS PATTERN UNFOLD...SOUTHERN ALASKA WILL REMAIN
ON THE COLD AND LARGELY DRY SIDE WELL INTO NEXT WEEK...WITH THE
GREATEST PRECIPITATION THREATS RELEGATED TO KODIAK ISLAND AND THE
NORTH GULF COAST. BLOWING DUST/SILT ORIGINATING FROM THE MATANUSKA
VALLEY MAY BECOME A PROBLEM ACROSS PARTS OF COOK INLET AND THE VALLEY
GIVEN THE MEAGRE SNOW PACK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 132 150 155 160 165 170 172-176 180.
         HEAVY FREEZING SPRAY 181 185.
FIRE WEATHER...NONE.

AHSENMACHER FEB 14