Blizzard in Alaska, March 22 to 23, 2008

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
150 PM ADT SAT MAR 22 2008

.ANALYSIS AND UPPER LEVELS...VERY LARGE SCALE UPPER LEVEL CYCLONIC
CIRCULATION NOW COVERS MOST OF THE STATE OF ALASKA FROM THE NORTH
SLOP SOUTH TO THE NORTHEAST PACIFIC AND WESTWARD TO THE CENTRAL
BERING. THERE ARE A FEW LOW CENTERS EMBEDDED WITHIN THE CIRCULATION.
ONE OVER THE GULF OF ALASKA AND ANOTHER SOUTH OF THE GULF ARE
ROTATING AROUND EACH OTHER. AN OCCLUDED FRONT EXTENDS FROM THE LOW
OVER SOUTHWEST GULF NORTHEAST TO AROUND CORDOVA. THIS FRONT IS
SWINGING NORTHWESTWARD TOWARD SOUTHCENTRAL. THE AIR MASS OVER THE
GULF REGION IS QUITE UNSTABLE AS EVIDENCED BY THE COLD CLOUD TOPS IN
SATELLITE IMAGERY (-40 TO -50 DEGREES CELSIUS) AS WELL AS CELLULAR
NATURE OF PRECIPITATION AS SEEN IN SATELLITE AND RADAR IMAGERY. 12Z
KODIAK SOUNDING INDICATED A LIFTED INDEX OF 2.2. A SHIP REPORT OVER
THE NORTH CENTRAL GULF REPORTED A THUNDERSTORM AROUND 18Z THIS
MORNING. TO THIS POINT MOST OF THIS CONVECTION HAS REMAINED OVER THE
GULF...BUT BANDS OF SHOWERS ARE NOW STARTING TO ROTATE ACROSS PRINCE
WILLIAM SOUND AND INTO KODIAK ISLAND. A NEW SURFACE LOW IS DEVELOPING
BETWEEN THE GULF/NE PACIFIC LOW AND RIDGE OVER WESTERN NORTH AMERICA
AND TRACKING NORTHWARD TOWARD THE EASTERN GULF.

NORTHERLY FLOW BACK OVER THE BERING SEA CONTINUES TO USHER COLD AIR
SOUTHWARD AND PRODUCE GUSTY WINDS AND STEADY SNOW SHOWERS ACROSS THE
REGION. WINDS ARE ESPECIALLY STRONG THROUGH THE GAPS IN THE ALASKA
PENINSULA WITH GUSTS TO 60 KT BEING REPORTED IN SHIP OBSERVATIONS.
ENHANCED DOWNWARD MOTION BEHIND UPPER LEVEL WAVES ROTATING ACROSS
THE PENINSULA IS LIKELY SUPPORTING THE GUSTS TO 77 KT THAT HAVE BEEN
OBSERVED IN KING COVE. A BLIZZARD WARNING WAS ISSUED THIS MORNING
FOR KING COVE AND THE REST OF THE SOUTHERN ALASKA PENINSULA. THE
THIRD UPPER LOW CENTER REFERENCED ABOVE IS DROPPING SOUTHWARD ACROSS
THE NORTHERN BERING SEA. THERE IS VERY LITTLE IN THE WAY OF CLOUDS
ASSOCIATED WITH THIS LOW...BUT ANOTHER ROUND OF COLD ADVECTION WILL
ACCOMPANY THE LOW.

.MODEL DISCUSSION...ALL MODELS INITIALIZED FAIRLY WELL WITH LOW
POSITIONS ARE SOLUTIONS ARE IN MUCH BETTER AGREEMENT THAN PAST RUNS
WITH MULTIPLE LOWS SWIRLING AROUND THE GULF THE NEXT FEW DAYS. THE
REST OF THE MODELS JOINED THE GFS IN TRACKING THE LOW CURRENTLY
DEVELOPING OVER NORTHEAST PACIFIC TO THE NORTHERN GULF ON SUNDAY.
THERE ARE STILL SOME MINOR DIFFERENCES IN LOW POSITIONS...BUT NOTHING
THAT WILL RESULT IN A HUGE DIFFERENCE IN THE FORECAST. THUS...WILL
CONTINUE TO STICK CLOSE TO THE GFS SOLUTION.

.SHORT TERM FORECAST...THE OCCLUDED FRONT WILL SWING WESTWARD TONIGHT
OVER SOUTHERN PORTIONS OF SOUTHCENTRAL AND WEAKEN AS THE LOW CENTER
OVER THE SOUTHWESTERN GULF SINKS SOUTHWARD AND DEVELOPING LOW MOVES
NORTHWARD INTO FAR EASTERN GULF. BULK OF SNOW SHOWERS WILL REMAIN
ALONG THE GULF COASTAL SECTIONS...AND SOME OF THESE WILL BE HEAVY.
KODIAK...WHICH HAS BEEN OBSERVING A MIX OF RAIN AND SNOW WILL SWITCH
BACK TO ALL SNOW AS COLDER AIR ALOFT MOVES IN WITH THE OCCLUSION.
AREAS INLAND MAY SEE A ROGUE SHOWER...BUT IF SO IT WILL BE
SHORT-LIVED. THE DEVELOPING LOW WILL TAKE A MORE NORTHERLY TRACK ON
SUNDAY TO THE KENAI PENINSULA LATE SUNDAY. THIS WILL PROVIDE A BETTER
SHOT AT A FEW SNOW SHOWERS OVER INLAND LOCATIONS LATE SUNDAY
AFTERNOON THROUGH SUNDAY NIGHT. THERE WILL ALSO BE SOME FAIRLY STRONG
UPPER LEVEL WAVES EMBEDDED IN THE UPPER FLOW SUNDAY THAT WILL MOVE
ACROSS SOUTHCENTRAL AND THEN OVER TO SOUTHWEST ALASKA ON MONDAY. THE
PATTERN LOOKS LIKE IT WILL PROGRESS EASTWARD A BIT BY MID WEEK WITH
UPPER CYCLONIC CIRCULATION BECOMING AN OPEN TROUGH AND MOVING TO
SOUTHEAST ALASKA. THUS...SHOWER ACTIVITY WILL BEGIN TO DIMINISH BY
LATE TUESDAY AND SLIGHTLY COLDER AIR WILL FILTER IN FROM THE NORTH
AND WEST.

OUT WEST...THE UPPER LOW OVER THE NORTHERN BERING WILL DROP DOWN INTO
THE NORTH PACIFIC BY SUNDAY MORNING. COLD ADVECTION BEHIND IT WILL
STRENGTHEN WINDS OVER MUCH OF THE CENTRAL TO EASTERN BERING...THE
EASTERN ALEUTIANS AND THE ALASKA PENINSULA TONIGHT THROUGH SUNDAY.
THIS WILL MAINTAIN BLIZZARD CONDITIONS ALONG THE SOUTHERN ALASKA
PENINSULA. THE WARNING CURRENTLY GOES THROUGH THE MORNING SO WILL
NEED TO CONSIDER EXTENDING THROUGH LATER SUNDAY. YET ANOTHER UPPER
LOW WILL DROP DOWN ACROSS THE BERING SEA SUNDAY AND SUNDAY NIGHT
BRINGING MORE COLD AIR. SO THE THREAT OF BLIZZARD CONDITIONS WILL
CONTINUE THROUGH AT LEAST SUNDAY NIGHT...BUT SURFACE PRESSURE
GRADIENT WILL SLACKEN A BIT AS GULF LOWS WEAKEN. THERE IS ALSO
CURRENTLY A BLIZZARD WATCH FOR THE EASTERN ALEUTIANS FOR TONIGHT.
REPORTS FROM THIS MORNING INDICATED WORST CONDITIONS WERE IN DUTCH
HARBOR AND VISIBILITIES IMPROVED AS HEADED ONSHORE AND TO THE
PACIFIC SIDE. SINCE DONT EXPECT MUCH INCREASE IN INTENSITY OF SNOW
AND EXPECT CHARACTER OF PRECIPITATION TO REMAIN SHOWERY...WILL
CANCEL WATCH AND STRONGLY WORD THE ZONE FORECAST. BOTTOM LINE FOR
THE CENTRAL TO BERING SEA REGION...SNOW SHOWERS AND GUSTY WINDS WILL
PERSIST THROUGH AT LEAST LATE TUESDAY. AS PATTERN BEGINS TO PROGRESS
A SYSTEM WILL APPROACH THE WESTERN ALEUTIANS AND WINDS AND SNOW
SHOWERS WILL DIMINISH OVER THE CENTRAL TO EASTERN BERING.

.LONG TERM FORECAST...ALTHOUGH THE PATTERN SHIFTS EASTWARD BY MID
WEEK THE MEAN POSITION OF TROUGH REMAINS OVER EASTERN PORTION OF
OUR FORECAST AREA THROUGH THE EXTENDED...SO DONT EXPECT ANY MAJOR
CHANGES IN THE WEATHER.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 181.
MARINE...GALE WARNING 150 155 165 170 171 172 179.
         HEAVY FREEZING SPRAY WARNING 150 155 165 170 171.
FIRE WEATHER...NONE.

SEB MAR 08