Snow Advisory 29, NWS Anchorage, AK

000 
WWAK42 PAFC 311408
WSWALU

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE ANCHORAGE AK
508 AM AST MON DEC 31 2007

AKZ161-010100-
/X.CON.PAFC.SN.Y.0029.000000T0000Z-080101T0100Z/
BRISTOL BAY-
INCLUDING THE CITIES OF...KING SALMON...DILLINGHAM...NAKNEK...
PILOT POINT
508 AM AST MON DEC 31 2007

...SNOW ADVISORY REMAINS IN EFFECT UNTIL 4 PM AST THIS
AFTERNOON NORTH AND EAST OF KING SALMON...

A SNOW ADVISORY REMAINS IN EFFECT UNTIL 4 PM AST THIS AFTERNOON
NORTH AND EAST OF KING SALMON.

SNOW WILL PERSIST NORTH AND EAST OF KING SALMON THROUGH THIS
AFTERNOON. SEVERAL INCHES OF SNOW HAS FALLEN SO FAR...AND AN
ADDITIONAL 3 TO 8 INCHES ARE EXPECTED TODAY...BRINGING THE STORM
TOTAL ACCUMULATIONS TO 6 TO 12 INCHES. THE HIGHEST AMOUNTS WILL BE
NORTH OF ILIAMNA.

A SNOW ADVISORY MEANS THAT PERIODS OF SNOW WILL CAUSE PRIMARILY
TRAVEL DIFFICULTIES. BE PREPARED FOR SNOW COVERED ROADS AND
LIMITED VISIBILITIES...AND USE CAUTION WHILE DRIVING.

$$

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
300 PM AST SUN DEC 30 2007

.MODEL DISCUSSION...ESPECIALLY FOR AN ACTIVE WINTER PATTERN...THE
MODELS ARE IN VERY NICE AGREEMENT. THE ONLY SIGNIFICANT AREA THEY ARE
HAVING DIFFICULTY RESOLVING IS WHEN AND WHERE A TRIPLE POINT MIGHT
DEVELOP LONG THE FRONT IN THE BERING SEA. THE ECMWF WANTS TO DEVELOP
ONE IN THE ADAK AREA MONDAY NIGHT WHILE THE GFS AND NAM PLACE A WEAK
ONE WELL SOUTH OF NIKOLSKI AT THAT TIME. THIS WILL MAKE A LITTLE
DIFFERENCE IN THE PRECIPITATION AT THAT TIME FOR THE CENTRAL
ALEUTIANS BUT WILL BE BRIEF AND HAVE LITTLE OVERALL EFFECT AS ALL
MODELS DISSIPATE THEIR TRIPLE POINTS TUESDAY MORNING. WEDNESDAY
THROUGH FRIDAY THE MODELS BEGIN TO DIVERGE IN THE PLACEMENT OF A LOW
IN THE GULF OF ALASKA. THE GFS IS RATHER CONSISTENT IN ITS SOLUTION
WITH THIS LOW AND THIS SOLUTION LOOKS REASONABLE FOR THREE TO FIVE
DAYS OUT.

.ANALYSIS AND UPPER LEVELS...MAIN LOW EFFECTING THE WEATHER TODAY IS
LOCATED SOUTH OF THE ALASKA PENINSULA WITH A FRONT EXTENDING OVER THE
PENINSULA. THE UPPER LEVEL SUPPORT FOR THIS LOW IS WELL EAST OF THE
SURFACE LOW AND IS SEEN IN SATELLITE STARTING AROUND 40N AND HEADING
UP THE 155W MERIDIAN INTO THE EASTERN BRISTOL BAY ZONE.
THE EASTERN PART OF THE FORECAST AREA EXPERIENCED SOME SNOW THIS
MORNING AS A SHORT WAVE PASSED THROUGH THE AREA. THIS WAVE IS NOW
EXITING THE COPPER RIVER BASIN TO THE NORTHEAST AND WILL REMAIN OUT
OF THE AREA.
THE MAJORITY OF THE BERING SEA AREA IS UNDER NORTHWEST FLOW EXCEPT
FOR THE WESTERN BERING SEAS AND WESTERN ALEUTIANS WHICH ARE ALREADY
COMING UNDER THE INFLUENCE OF THE NEXT WEATHER SYSTEM TO THE WEST.
THE LOW IN THIS SYSTEM WILL REMAIN WEST OF THE FORECAST AREA BUT THE
WEATHER FRONT WILL MOVE INTO THE WESTERN BERING SEA TONIGHT AND THEN
INTO THE CENTRAL BERING SEA MONDAY NIGHT BEFORE WEAKENING TUESDAY

.SHORT TERM FORECAST...A BLIZZARD WARNING IS IN EFFECT THROUGH
TONIGHT FOR THE ALASKA PENINSULA DUE TO THE LOW SOUTH OF THERE AND
THE WEATHER FRONT STATIONARY OVER THEM. WINDS HAVE BEEN GUSTING 40 TO
60 MPH WITH SAND POINT AND COLD BAY BOTH EXPERIENCING VISIBILITIES TO
ONE QUARTER MILE OR LESS DUE TO BLOWING SNOW IN THESE WINDS.
KODIAK...SOUTHERN KENAI PENINSULA...AND THE EASTERN BRISTOL BAY ZONE
WILL SEE SNOW WITH THIS SYSTEM OVERNIGHT AS THE MOISTURE OVERRIDES
THE COLD AIR IN PLACE. THE EXCEPTION TO THIS WILL BE KODIAK ISLANDS
WHERE THE WARMER AIR IN THIS SYSTEM WILL CAUSE TO THE SNOW TO TURN TO
RAIN OR A RAIN SNOW MIX AS IT HAS ALREADY DONE IN THE SOUTHERN PART
OF THE ISLAND.

.LONG TERM FORECAST...AFTER THE SYSTEM SOUTH OF THE ALASKA PENINSULA
DISSIPATES TUESDAY THE MIDDLE PART OF THE WEEK LOOK TO BE MOSTLY DRY
AND COLD WITH WEAK SURFACE HIGH PRESSURE OVER THE STATE AND A COLD
TROUGH ALOFT. AFTER THAT THERE IS A CHANCE OF SOME SNOW ALONG THE
NORTH GULF COAST AND INTO THE ANCHORAGE AREA LATE IN THE WEEK WITH
MODELS FORMING A PERSISTENT WEAK LOW SOMEWHERE BETWEEN MIDDLETON
ISLAND AND PRINCE WILLIAM SOUND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 181.
MARINE...GALE 120 130 132 138 150 155 160 165 170 171 172.
         STORM 175 176.
HEAVY FREEZING SPRAY 130 140 155 160 165 180 185.
FIRE WEATHER...NONE.

DEC 07