Blizzard and Heavy Snow in Alaska, March 8 to 9, 2010

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 PM AKST SUN MAR 7 2010

.MODEL DISCUSSION...MODEL INITIALIZATION IS VERY GOOD AND MODEL
CONSISTENCY IS GOOD THROUGH AT LEAST MONDAY AFTERNOON. THERE IS SOME
DIFFERENCE OS TO THE TRACK ON THE STRENGTHENING LOW THAT WILL MOVE
INTO THE COOK INLET REGION MONDAY AND MONDAY NIGHT BETWEEN THE
MODELS. THE MOST SIGNIFICANT DIFFERENCE BETWEEN MODELS HERE IS THAT
THE NAM DEVELOPS ANOTHER MESO LOW IN THE MIDDLE OF COOK INLET MONDAY
NIGHT INTO TUESDAY. A MESO LOW DEVELOPED YESTERDAY IN COOK INLET
AFTER THE PASSAGE OF THE PREVIOUS LOW AND THAT FEATURE HAD A
PRONOUNCED IMPACT ON THE WEATHER IN THAT REGION. THE DEVELOPMENT OF
ANOTHER ONE MONDAY NIGHT LOOKS LIKELY SO THE NAM SHOULD BE USED THERE
DURING THAT TIME PERIOD. IN THE WESTERN PART OF THE FORECAST ARE THE
GFS LOOKS GOOD BUT JUST A LITTLE TOO AMBITIOUS AS TO THE STRENGTH OF
THE LOW. BACKED OFF A FEW MB AND BASICALLY SPLIT THE DIFFERENCE IN
CENTRAL PRESSURES THAT THE GFS AND ECMWF HAVE.

.ANALYSIS AND UPPER LEVELS...A COLD UPPER LEVEL LOW CENTERED IN THE
NORTHERN BERING SEA IS THE DOMINANT UPPER LEVEL FEATURE OVER THE AREA
TODAY. THE 250 MB JET STREAM RUNS DUE WEST TO EAST NEAR 50N FROM
SOUTH OF THE KAMCHATKA PENINSULA TO SOUTH OF KODIAK ISLAND. THERE IS
A LARGE AREA OF THIS JET WHERE SPEEDS ARE IN EXCESS OF 150 KT WITH A
PEAK NEAR 180 KT. THIS JET IS CURRENTLY FEEDING A STRENGTHENING LOW
THAT IS APPROACHING KODIAK ISLAND. THIS LOW IS SIMILAR TO THE ONE
THAT MOVED THROUGH THE AREA FRIDAY AND SHOULD ALSO DEVELOP A MESO LOW
IN COOK INLET MONDAY NIGHT. AS THE NAM MODEL HAS FORECAST.

.SHORT TERM FORECAST...THE BIG STORY IN THE EASTERN PART OF THE
FORECAST AREA IS THE APPROACHING LOW THAT WILL BE CENTERED JUST SOUTH
OF THE KENAI PENINSULA BY MONDAY AFTERNOON. CLOUDS WILL INCREASE IN
THE AREA OVERNIGHT WITH PRECIPITATION MOVING INTO UPSLOPE AREAS AFTER
THAT. THERE IS A BLIZZARD WATCH FOR THE EASTERN KENAI PENINSULA AND
ALSO FOR THOMPSON PASS WITH THE INCREASING WINDS AND BLOWING SNOW
THAT WILL DEVELOP MONDAY.
EXCEPT FOR THE WEST SIDE OF THE INLET...THE COOK INLET REGION WILL
DOWNSLOPE OUT THE PRECIPITATION AT FIRST AND THEN THE WILD CARD WILL
BE THE EXPECTED DEVELOPMENT OF A COOK INLET MESO LOW MONDAY NIGHT
THIS WILL ENHANCE PRECIPITATION IN THE AREA AND MAY BRING MORE GUSTY
WINDS AND REDUCED VISIBILITIES IN BLOWING SNOW TO KACHEMAK BAY.

THE KUSKOKWIM DELTA WILL NEED TO BE WATCHED FOR WIND CHILLS. WINDS
WILL WEAKEN OVERNIGHT BUT THEN NORTHWEST WINDS WILL INCREASE BY
MONDAY NIGHT AS TEMPERATURES WILL BE WELL BELOW ZERO. IT LOOKS LIKELY
THAT A WIND CHILL ADVISORY WILL BE NEEDED.

THE ALASKA PENINSULA AND BRISTOL BAY WILL SEE SOME SNOW AND BLOWING
SNOW OVERNIGHT WITH THE LOW THAT IS MOVING TOWARD KODIAK ISLAND. THE
BIG FORECAST UNCERTAINTY IS WHETHER THERE WILL BE ENOUGH WIND AND
BLOWING SNOW FOR A BLIZZARD WARNING IN THESE AREAS. AS OF RIGHT NOW
IT LOOKS LIKE THE GREATEST BLIZZARD POTENTIAL IS IN THE 161 ZONE WITH
ANY BLIZZARD CONDITIONS IN 181 BEING SHORT LIVES AND IN THE EASTERN
SECTION.

THE BERING SEA AREA WILL REMAIN IN WEST TO NORTHWEST FLOW KEEPING
SNOW SHOWERS PREVALENT. THE BIG UNCERTAINTY IS WHEN A POLAR VORTEX
DEVELOPS IN THIS COLD ADVECTION OFF THE ICE EDGE. WHEN ONE OF THE
VORTEXES SPINS UP IS CAN CAUSE SOME LOCALLY GUSTY WINDS AND INTENSE
SNOW SHOWERS AS IT PASSES THROUGH. THESE FEATURES ARE BEST SEEN ON
THE VISIBLE SATELLITE AND TWO CAN BE SEEN THIS AFTERNOON...NEAR 56N
178W AND ALSO NEAR 57N 175E.

.LONG TERM FORECAST...COLDER TEMPERATURES FOR MUCH OF SOUTH CENTRAL
AND SOUTHWESTERN ALASKA WILL BE IN STORE AS THE UPPER LOW MOVES
OVERHEAD AND FLOW GENERALLY BECOMES NORTHWESTERLY. WEATHER SHOULD
CALM DOWN BY LATER IN THE WEEK AS STORM TRACKS SHIFT FARTHER SOUTH IN
RESPONSE TO THE UPPER LOW MOVING SOUTH...ALTHOUGH SNOW SHOWERS ARE
EXPECTED TO LINGER ALONG THE NORTHERN GULF COAST FOR MUCH OF THE
EXTENDED PERIOD.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 125 131 161.
         HIGH WIND WARNING 135.
MARINE...GALE 129 141 160 165 172 180.
   STORM 125 130 132 138 140 150 155.
   HURRICANE FORCE 120.
   HEAVY FREEZING SPRAY 121 129 130 132 138 140 141 150 155 165 170.
FIRE WEATHER...NONE.

EZ MAR 10