Gale Warning 107, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
500 PM AKST TUE JAN 29 2013

.ANALYSIS AND UPPER LEVELS...
SATELLITE IMAGERY REVEALS TWO AREAS OF LOW PRESSURE OVER THE BERING
SEA THIS AFTERNOON...WITH THE NORTH PACIFIC UPPER LOW WHICH HAS BEEN
THE MAIN FEATURE OF INTEREST FOR THE PAST FEW DAYS MOVING OVER THE
EASTERN ALEUTIANS AND A LARGER CLOSED UPPER LOW DRIFTING WESTWARD
JUST NORTH OF THE WESTERN PART OF THE CHAIN. AN UPPER LEVEL RIDGE
OVER THE EASTERN PACIFIC CONTINUES TO SHIFT EASTWARD...WITH AN AXIS
EXTENDING THROUGH SOUTHCENTRAL AK AND INTO THE INTERIOR. AN
APPROXIMATELY 978 MB SURFACE LOW HAS MOVED INTO THE EASTERN BERING
AND IS NOW APPROACHING THE PRIBILOF ISLANDS WITH A FRONT EXTENDING
EASTWARD ACROSS THE AKPEN AND INTO THE NORTHERN GULF OF ALASKA. SNOW
SHOWERS CONTINUE ACROSS SOUTHERN ALASKA AHEAD OF THE FRONT...WITH
RAIN FALLING SOUTH OF THE BOUNDARY OVER THE AKPEN AND KODIAK ISLAND
WHERE TEMPERATURES HAVE WARMED ABOVE FREEZING. STRONG WINDS CONTINUE
TO SUPPORT BLIZZARD CONDITIONS ALONG COASTAL PORTIONS OF THE
KUSKOKWIM DELTA.

.MODEL DISCUSSION...
MODELS ARE IN GENERAL AGREEMENT WITH RESPECT TO THE OVERALL SYNOPTIC
PATTERN THROUGH LATE IN THE WEEK. A BROAD LONGWAVE TROUGH WILL
DEVELOP OVER THE BERING AS THE UPPER LOW CURRENTLY NEAR THE WESTERN
ALEUTIANS DRIFTS WESTWARD AND THEN DROPS SOUTH OF THE CHAIN. THE
RIDGE OVER THE EASTERN PACIFIC WILL CONTINUE TO MOVE EASTWARD AS
ANOTHER NORTH PACIFIC LOW APPROACHES THE SOUTHERN GULF ON FRIDAY.

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
PRECIPITATION WILL CONTINUE INTO THURSDAY AS A SERIES OF FRONTS MOVE
OVER THE NORTHERN GULF COAST. WITH THE EXCEPTION OF KODIAK
ISLAND...PRECIPITATION WILL STAY ALL SNOW TONIGHT AND BE MOST
PREVALENT ALONG THE COAST WITH SCATTERED SHOWERS INLAND. THE MAIN
FORECAST CONCERN ON WEDNESDAY WILL BE PRECIPITATION TYPE AS
TEMPERATURES CONTINUE TO WARM WITH THE NORTHWARD PROGRESSION OF THE
FRONT. WILL HAVE TO MONITOR THE POTENTIAL FOR FREEZING RAIN FROM THE
KENAI PENINSULA THROUGH THE ANCHORAGE BOWL AND MATANUSKA VALLEY
BEGINNING WEDNESDAY MORNING AS WARMER AIR MOVES IN ALOFT AND SURFACE
TEMPERATURES REMAIN BELOW FREEZING. PRECIPITATION WILL THEN CHANGE
BACK OVER TO SNOW DURING THE EVENING HOURS. FURTHER
NORTH...SIGNIFICANT SNOWFALL AMOUNTS WILL BE LIKELY OVER THE SUSITNA
VALLEY. INLAND LOCATIONS WILL CONTINUE TO SEE SNOW SHOWERS ON
THURSDAY...WITH A RAIN/SNOW MIX FOR COASTAL LOCATIONS.

SOUTHWEST ALASKA...
BLIZZARD CONDITIONS WILL REMAIN POSSIBLE INTO THE EVENING HOURS FOR
COASTAL PORTIONS OF THE KUSKOKWIM DELTA AS SNOW AND STRONG EASTERLY
WINDS LEAD TO REDUCED VISIBILITIES. PRECIPITATION WILL CONTINUE
THROUGH WEDNESDAY NIGHT OVER THE REST OF THE SOUTHWEST MAINLAND AS
MOIST ONSHORE FLOW CONTINUES...WITH A MIX OF RAIN AND SNOW OVER
BRISTOL BAY AND THE KUSKOKWIM DELTA AND ALL SNOW OVER THE LOWER
KUSKOKWIM VALLEY.

ALEUTIANS/BERING SEA...
SNOW OVER THE PRIBILOFS WILL TAPER OFF DURING THE MORNING AS THE
SURFACE LOW MOVES OFF TO THE NORTH AND EVENTUALLY DISSIPATES. THE
WEATHER PATTERN OVER THE BERING WILL THEN BE FAIRLY BENIGN THROUGH
THURSDAY AS THE CLOSED UPPER LOW NEAR THE WESTERN ALEUTIANS DRIFTS
WESTWARD AND BRINGS SCATTERED SNOW SHOWERS TO THAT PART OF THE CHAIN.

.LONG TERM FORECAST...
A CHANCE OF PRECIPITATION WILL REMAIN IN THE FORECAST FOR MUCH OF
SOUTHERN ALASKA INTO THE EXTENDED TERM AS A LONG WAVE TROUGH OVER THE
BERING GRADUALLY EXPANDS EASTWARD THROUGH THE END OF THE WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 155
         FREEZING RAIN ADVISORY 101 111 121
         WINTER WEATHER ADVISORY 145
MARINE...GALE WARNING 120 127 130 138 180 185
         HEAVY FREEZING SPRAY 127 130 140
FIRE WEATHER...NONE

CB JAN 13