Heavy Freezing Spray Warning 244, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
210 PM AKST TUE DEC 25 2012

.ANALYSIS AND UPPER LEVELS...

UPPER LEVEL LOW OVER THE FAR WESTERN BERING REMAINS STATIONARY...WITH
SOUTHWESTERLY FLOW PROPELLING EMBEDDED DISTURBANCES NORTH AND EAST
FROM THE NORTH PACIFIC TO THE WESTERN GULF...EASTERN BERING...AND
SOUTHWESTERN MAINLAND. A SHARPLY DEFINED UPPER LEVEL TROUGH EXTENDS
FROM THE NORTHERN BERING SOUTH AND EAST INTO THE CENTRAL GULF AND
THEN FARTHER SOUTH AND EAST INTO THE NORTHEAST PACIFIC. A
PERSISTENTLY QUASI-STATIONARY SOUTHEASTERLY JET STREAK IS FINALLY
SHOWING SIGNS OF WEAKENING AND MOVING NORTH TODAY INTO THE
INTERIOR...AND SERVES AS THE PRIMARY REASON FOR MODERATE TO HEAVY
SNOWFALL THE LAST COUPLE OF DAYS ACROSS THE KENAI PENINSULA.

.MODEL DISCUSSION...

MODELS ARE IN GREAT AGREEMENT IN THE SHORT TERM...WHICH IS SURPRISING
IN THAT THE WEATHER PATTERN WILL BE VERY ACTIVE THROUGH THE END OF
THE WEEK...BUT NOT SURPRISING IN THAT ALL OF THE LOW PRESSURE SYSTEMS
WILL BE FAIRLY WELL-DEFINED.

.SHORT TERM FORECAST...

SOUTHCENTRAL...

LIGHT SNOW WITH MINOR IF ANY ACCUMULATIONS WILL CONTINUE THROUGH THE
EVENING OVER MUCH OF SOUTHCENTRAL FROM ANCHORAGE AND PALMER NORTH AND
WEST. DRYING WILL COMMENCE BY LATE TONIGHT INLAND BEFORE THE NEXT
SYSTEM ARRIVES FROM THE SOUTH WEDNESDAY. THIS FRONT WILL BRING RAIN
TO THE KODIAK ISLAND AREA BY WEDNESDAY MORNING AND THEN MOVE TO THE
NORTH GULF COAST LATER IN THE DAY. THIS FRONT WILL ESSENTIALLY DIE AS
IT MOVES TO THE GULF COAST AS THERE IS VERY LITTLE UPPER LEVEL
SUPPORT TO PUSH IT INLAND BY THE TIME IT REACHES SOUTHCENTRAL. EXPECT
ENHANCEMENT TO THE PRECIPITATION ESPECIALLY OVER WESTERN PRINCE
WILLIAM SOUND...AS WELL AS STRONG WINDS OVER THE NORTHERN GULF AS A
BARRIER JET BECOMES WELL ESTABLISHED WEDNESDAY THROUGH THURSDAY
NIGHT. THIS PARTICULAR SYSTEM WILL BRING WARMER AIR NORTH INTO THE
REGION...SO PRECIPITATION SHOULD FALL MAINLY AS A MIX OF RAIN AND
SNOW AT LOWER ELEVATIONS...WITH SNOW AND SOME RAIN AT HIGHER
ELEVATIONS ALONG EASTERN TURNAGAIN ARM AND PORTAGE VALLEY. THE
NORTHERN AND WESTERN SLOPES OF THE CHUGACH RANGE SHOULD EXPERIENCE
ONLY DOWNSLOPE DRYING.

SOUTHWEST ALASKA...

MOSTLY CLOUDY SKIES WITH ISOLATED SNOW SHOWERS WILL GIVE WAY TO
INCREASING OFFSHORE FLOW TONIGHT AND WEDNESDAY. WEATHER FRONT ARRIVES
WEDNESDAY MORNING TO THE BRISTOL BAY REGION AND WILL PUSH NORTH
THROUGH THURSDAY. SNOW AND BLOWING SNOW ON THE NORTHWESTERN SIDE OF
THE SYSTEM WILL SLOWLY GIVE WAY TO FREEZING RAIN OR RAIN FROM
SOUTHEAST TO NORTHEAST ACROSS THE REGION AS MUCH WARMER AIR MOVES
INTO THE REGION.

BERING SEA/ALEUTIANS...

STRONG LOW PRESSURE ORGANIZES OVER THE NORTH PACIFIC TODAY AND THEN
PUSHES A FRONT NORTH INTO THE ALASKA PENINSULA TONIGHT. STORM FORCE
WINDS WILL AFFECT THE COASTAL WATERS SOUTH OF THE ALASKA
PENINSULA...WITH WRAPAROUND SNOW...WIND...AND SOME RAIN AFFECTING
DUTCH HARBOR ON THE BACKSIDE OF THE LOW BEFORE CHANGING BACK TO ALL
SNOW LATE WEDNESDAY MORNING OR WEDNESDAY AFTERNOON. THE WESTERN AND
CENTRAL ALEUTIANS WILL REMAIN FAIRLY QUIET UNTIL WEDNESDAY EVENING
WHEN RAIN AND SNOW ASSOCIATED WITH A WARM FRONT PUSHES NORTH AND
BECOMES STATIONARY ACROSS THE AREA WEDNESDAY NIGHT AND THURSDAY.

.LONG TERM FORECAST...

ALL MODELS AGREE ON AN ACTIVE AND WARM WEATHER PATTERN WELL INTO THE
NEXT WEEK. MULTIPLE LOWS ARE EXPECTED TO MOVE ACROSS THE REGION
BRINGING PERIODS OF STRONGER WINDS AND PRECIPITATION WITH THEM
THROUGH EARLY NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WATCH...155
MARINE...GALES...120 125 132 140 155 160 165 171 172 175 180
         STORMS...130 138 150 170 176
         HVY FRZG SPRY...185
FIRE WEATHER...NONE.

CC DEC 12