Blizzard in Alaska, March 6, 2008

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AST THU MAR 6 2008

.MODEL DISCUSSION...MODELS IN GOOD AGREEMENT THROUGH 48 HOURS.
DIVERGENCE BEGINS FRIDAY EVENING AS LOW PROGGED TO BE NEAR KODIAK
ISLAND MOVES INLAND. ECMWF WANTS TO RAPIDLY WEAKEN THE LOW AS IT
MOVES INTO THE WESTERN INTERIOR. THE GFS NAM AND UKMET MAINTAIN ITS
INTENSITY BUT DISAGREE ON THE LOWS TRACK. GFS HAS HAD GOOD RUN TO RUN
CONSISTENCY AND IS THE PREFERRED MODEL FOR OPERATIONAL PURPOSES.

.UPPER LEVELS...
UPPER LEVEL PATTERN IS PROGRESSIVE. RIDGE ALOFT OVER MAINLAND ALASKA
AND WESTERN CANADA WILL EDGE EASTWARD FURTHER AND FURTHER INTO CANADA
THROUGH THE NEXT 72 HOURS AND BEYOND. MEANWHILE A LARGE DEEP UPPER
LOW OVER THE BERING SEA AND CENTRAL ALEUTIANS EDGES EASTWARD
WEAKENING IN THE PROCESS.

.SURFACE FEATURES...
THE OLD LOW 976 MB LOW OVER THE ALASKA PENINSULA WILL DISSIPATE NEAR
THE PRIBILOF ISLANDS FRI AFTERNOON. A SMALL 982 MB LOW JUST SOUTH OF
ADAK DISSIPATES SOUTH OF THE ALASKA PENINSULA FRI NIGHT. A NEW 980 MB
LOW OUT OF THE NORTH PACIFIC WILL BE THE MAIN WEATHER MAKER. IT IS
HEADING DUE NORTH TOWARD KODIAK ISLAND AND WILL BECOME A 969 MB LOW
JUST EAST OF KODIAK ISLAND FRIDAY MORNING. THE LOW THEN MOVES INLAND
NEAR KAMISHAK BAY FRIDAY EVENING AND WEAKENS TO 983 MB OVER THE
WESTERN LOWER YUKON VALLEY FRIDAY NIGHT. THE ASSOCIATED WEATHER FRONT
WILL ENTER THE GULF OF ALASKA THIS AFTERNOON AND REACH THE NORTH GULF
COAST LATE TONIGHT AND THE SOUTHERN SLOPES OF THE ALASKA RANGE BY
FRIDAY NIGHT.

.SOUTHCENTRAL ALASKA AND KODIAK ISLAND...
STRONG SOUTHEAST WINDS HAVE DIMINISHED ACROSS SOUTHCENTRAL ALASKA FOR
THE MOMENT BUT STRONG WINDS ARE EXPECTED TO REDEVELOP THIS EVENING
THROUGH THE USUAL CHANNELED AREAS. TURNAGAIN ARM AND THE COPPER RIVER
DELTA ARE THE PRIMARY CONCERNS. HIGH WIND WATCHES HAVE BEEN ISSUED.
COPIOUS RAINFALL FROM THE LAST SYSTEM HAS LEFT SOME AREAS OF
SOUTHCENTRAL WITH URBAN FLOODING CONCERNS. THE NEXT FRONT IS LIKELY
TO EXACERBATE THIS PROBLEM AS IT TOO HAS PLENTY OF BOTH MOISTURE AND
LIFT. PRINCE WILLIAM SOUND AND THE KENAI PENINSULA WILL BE THE MOST
VULNERABLE.

.SOUTHWESTERN ALASKA AND THE ALASKA PENINSULA...
BRIEF BREAK TODAY THROUGH TOMORROW BEFORE NEXT LOW ARRIVES FRIDAY
NIGHT. SOUTHWESTERN ALASKA SHOULD REMAIN IN THE COLD QUADRANT OF THIS
NEXT SYSTEM SO IT SHOULD BE A GOOD SNOW MAKER.

.PRIBILOFS AND ALEUTIAN CHAIN...
WEAK TO MODERATE NORTHWESTERLY FLOW WILL CONTINUE TO SPREAD CAA SNOW
SHOWERS ACROSS THE PRIBILOF ISLANDS AND ALEUTIAN CHAIN THROUGH AT
LEAST THE WEEKEND.

.BEYOND 48 HOURS...
UPPER LEVEL STEERING FLOW WILL DIRECT EACH NEW NORTH PACIFIC STORM
ALONG A MORE AND MORE EASTWARD TRACK. THUS SOUTHERLY FLOW AND WARM
AIR ADVECTION OVER THE GULF OF ALASKA AND SOUTHERN MAINLAND WILL BE
REPLACED BY NORTHWESTERLY FLOW AND COLD AIR ADVECTION BY MONDAY
MORNING. EXPECT SURFACE TEMPS TO FALL BACK DOWN TOWARDS
CLIMATOLOGICAL NORMS BEGINNING THIS WEEKEND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HWW 101 125 135
MARINE...GALE  125 129 132 138 140 141
         STORM 120 130
         HEAVY SPRAY 185
FIRE WEATHER...NONE.

ASB MAR 08