High Wind in Alaska, January 1 to 2, 2011

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
439 AM AKST SAT JAN 1 2011

.MODEL DISCUSSION...

MODELS ARE IN GENERALLY GOOD AGREEMENT OVERALL. DIFFERENCES ARISE IN
THE EASTERN BERING...BRISTOL BAY...AND NORTH PACIFIC REGIONS IN
DEPICTING TRACK OF ANOTHER LOW PRESSURE SYSTEM WHICH WILL MOVE
NORTHEAST INTO THE AREA FROM THE NORTH PACIFIC LATE SUNDAY INTO
MONDAY. THE MORNING FORECAST PACKAGE WILL LEAN TOWARDS THE GFS
THROUGH SUNDAY NIGHT...THEN LEAN TOWARDS THE EUROPEAN MODEL (EC) FROM
MORNING MORNING ONWARD. THE NAM WAS PREFERRED FOR THE EAST DOMAIN
THROUGH SUNDAY NIGHT FOR ITS HIGHER RESOLUTION IN DETERMINING WIND
SPEED AND WITH ITS BETTER HANDLING OF TEMPERATURES THE LAST COUPLE OF
DAYS ACROSS THE REGION. FORECAST CONFIDENCE IS AVERAGE TO ABOVE
AVERAGE THROUGH SUNDAY...WHILE IT IS AVERAGE TO BELOW AVERAGE FROM
SUNDAY NIGHT ONWARD.

.ANALYSIS AND UPPER LEVELS...

A WEAK SYNOPTIC SCALE WARM FRONT IS SERVING AS A FOCUS OF
PRECIPITATION THIS MORNING AS IT MOVES NORTH THROUGH THE KUSKOKWIM
VALLEY AND EXTENDS ACROSS TO THE EAST TO PRINCE WILLIAM SOUND AND THE
FAR NORTHERN GULF. THIS FEATURE WILL REACH THE CENTRAL INTERIOR BY
EARLY THIS AFTERNOON. A 965 MB LOW PRESSURE SYSTEM IS LOCATED ABOUT
100 MILES SOUTHEAST OF SAINT GEORGE AND EXTENDS A COLD FRONT SOUTH
AND EAST INTO THE NORTH PACIFIC. THE SURFACE LOW WILL STRENGTHEN
THROUGH TONIGHT AS IT MOVES NORTH THROUGH THE EASTERN BERING...WITH
SOUTHERLY UPPER LEVEL FLOW PUSHING THE COLD FRONT NORTH AND EAST
THROUGH SOUTHWEST AND SOUTHCENTRAL ALASKA THROUGH SUNDAY MORNING.
THIS WILL INTRODUCE PRECIPITATION-TYPE PROBLEMS INTO THE FORECAST
WITH THE AVAILABILITY OF VERY WARM AIR IN ASSOCIATION WITH THE WARM
SECTOR OF THIS IMPRESSIVE STORM SYSTEM.

YET ANOTHER LOW WILL APPROACH THE BRISTOL BAY REGION FROM THE
NORTHWEST PACIFIC SUNDAY INTO MONDAY...AND PUSH A SERIES OF FRONTS
NORTH THROUGH THE GULF INTO THE NORTH GULF COAST LATE SUNDAY NIGHT
THROUGH AT LEAST MONDAY NIGHT AND PERHAPS BEYOND AS A
QUASI-STATIONARY LOW DEVELOPS IN THE VICINITY OF THE NORTHERN
AKPEN/BRISTOL BAY REGION.

.SHORT TERM FORECAST...

SOUTH AND EAST OF THE ALASKA RANGE...

WARM FRONT WILL REACH THE CENTRAL INTERIOR OF THE STATE BY THIS
AFTERNOON...PLACING ALL OF SOUTHCENTRAL IN AN IMPRESSIVE WARM SECTOR
REGIME. STRONG SOUTH-SOUTHEASTERLY FLOW WILL KEEP TEMPERATURES VERY
WARM FOR THIS TIME OF YEAR...AND ANCHORAGE AND PLACES ALONG THE
NORTHERN AND WESTERN SLOPES SHOULD REMAIN MAINLY DRY AS SOUTH AND
EAST FACING SLOPES OF THE ALASKA AND CHUGACH RANGES SEE SNOW INLAND
AND MOSTLY RAIN NEAR THE COAST. WITH PASSAGE OF THE WARM FRONT THE
PRESSURE GRADIENT WILL INCREASE THROUGH TURNAGAIN ARM AND STRONG
WINDS ARE EXPECTED UNTIL COLD FRONTAL PASSAGE SOMETIME TONIGHT. WE
WILL BE UPGRADING THE HIGH WIND WATCH TO A WARNING FOR TURNAGAIN ARM
AND HIGHER ELEVATIONS WITH THE MORNING FORECAST PACKAGE.

THE OTHER POTENTIAL BIG IMPACT THIS SYSTEM COULD DELIVER IS IN THE
SUSITNA VALLEY...WHERE A WINTER STORM WATCH IS POSTED FOR HEAVY SNOW.
THE BIG QUESTION WILL BE HOW MUCH WARM AIR MAKES IT INTO THE
REGION...AS MODEL PARTIAL THICKNESSES SUGGEST THAT THERE IS THE
POTENTIAL THAT THE SNOW MIXES WITH OF CHANGES OVER TO RAIN FOR A TIME
MOST PLACES BEFORE THE PRECIPITATION ENDS...THUS CUTTING INTO
ACCUMULATIONS. THE MORNING FORECAST PACKAGE WILL INCREASE
TEMPERATURES ACROSS THE ENTIRE REGION OVER THE NEXT FEW DAYS WITH
STRONG SOUTHERLY FLOW...AND WILL LEAVE THE WATCH AS IS FOR NOW AS
THERE IS STILL PLENTY OF TIME TO ASSESS MODEL TRENDS IN ASSOCIATION
WITH THE PRECIPITATION TYPE.

SOUTHWEST ALASKA...

SNOW DEVELOPED MOST AREAS OVERNIGHT...EXCEPT THIS MORNING THE WARM
SECTOR HAS COMPLETELY OVERTAKEN THE BRISTOL BAY ZONE AND WARMED
TEMPERATURES INTO THE MIDDLE TO UPPER 30S...CHANGING ALL OF THE
PRECIPITATION TO RAIN. WE HAVE CANCELED THE WINTER STORM WARNING FOR
BRISTOL BAY ZONE WITH THE MORNING FORECAST PACKAGE. THE WINTER STORM
WARNING FOR THE KUSKOKWIM DELTA AND FREEZING RAIN ADVISORY FOR THE
KUSKOKWIM VALLEY ZONES APPEAR TO BE ON TRACK AS SNOW SHOULD CHANGE TO
FREEZING RAIN BEFORE THE PRECIPITATION ENDS LATER TODAY.

BERING SEA/ALEUTIANS...

BLIZZARD CONDITIONS ARE FORECASTED TO CONTINUE ACROSS THE PRIBILOFS
ON THE BACK SIDE OF THE LOW. CONDITIONS SHOULD SLOWLY IMPROVE THERE
BY THIS EVENING...THOUGH SNOW SHOWERS WILL CONTINUE THROUGH SATURDAY
NIGHT BEFORE PERHAPS DIMINISHING...AND BLOWING SNOW COULD REMAIN AND
ISSUE WELL INTO THE EVENING HOURS. OTHERWISE...EXPECT SNOW SHOWERS TO
CONTINUE TO DIMINISH ACROSS THE ALEUTIANS AS HIGH PRESSURE AT THE
SURFACE KEEPS THINGS ON THE DRY SIDE THROUGH SUNDAY...BEFORE SNOW
WITH THE NEXT SYSTEM MOVING INTO THE REGION FROM THE SOUTH MOVES IN
SUNDAY NIGHT.

.LONG TERM FORECAST...

THE ACTIVE WEATHER PATTERN WILL CONTINUE FOR THE BEGINNING OF THE
WEEK...BEFORE SIGNS APPEAR OF ANOTHER PATTERN CHANGE. BY LATE NEXT
THERE ARE SIGNIFICANT MODEL DIFFERENCES...WITH ONE SET OF MODELS
TRYING TO DEVELOP A STRONG RIDGE ACROSS THE BERING SEA...WHILE
ANOTHER SET OF MODELS TRY TO DEVELOP THE RIDGE ACROSS THE GULF AND
THE SOUTHERN ALASKA MAINLAND. FOR NOW...DUE TO THE MODEL
DISCREPANCIES...STUCK MAINLY TO THE INHERITED FORECAST UNTIL MODELS
GAIN A BIT MORE CONSISTENCY. FORECAST CONFIDENCE FOR THE BEGINNING OF
THE WEEK IS ABOUT AVERAGE...DROPPING TO BELOW AVERAGE TOWARDS THE END
OF NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING...101
         BLIZZARD WARNING...195
         WINTER STORM WARNING...155
         FREEZING RAIN ADVISORY...152
         WINTER STORM WATCH...145
MARINE...GALES...120 125 129 130 132 138 140 141 150 155 160 165 170
                 171 172 179 180 185
         STORMS...NONE.
         HVY FRZG SPRY...185
FIRE WEATHER...NONE.

CC DEC 10