Blizzard in Alaska, February 15 to 16, 2008

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
100 PM AST FRI FEB 15 2008

.ANALYSIS AND UPPER LEVELS...
VERY ACTIVE WEATHER PATTERN IN PLACE. A STRONG NEARLY VERTICALLY
STACKED LOW PRESSURE SOUTH OF ADAK IS THE DOMINANT FEATURE THIS
AFTERNOON. SHORTWAVES AND WEAKER SURFACE LOWS CONTINUE TO ROTATE
AROUND MAINLY THE EAST SIDE OF THE LOW. ONE SUCH LOW SURFACE LOW
PRESSURE OVER COOK INLET THIS MORNING HAS DISSIPATED WITH SNOWFALL
TAPERING OFF...BUT NOT BEFORE BRINGING SIGNIFICANT SNOWFALL TO
PORTIONS OF SOUTHCENTRAL. VERY STRONG COLD ADVECTION OCCURRED ON THE
BACK SIDE OF THE LOW WITH GUSTY WINDS ESPECIALLY THROUGH KAMISHAK GAP
AND INTO COOK INLET AND KACHEMAK BAY. THE SOUTHWEST MAINLAND IS
ENJOYING A SHORTLIVED HIGH PRESSURE THIS AFTERNOON WITH THE HIGH
PRESSURE BEGINNING TO BUILD INTO SOUTHCENTRAL. THE LOW SOUTH OF ADAK
IS BRINGING WIDESPREAD GALES TO THE ALEUTIANS...AND SNOW AND BLOWING
SNOW TO MUCH OF THE REGION. WARMER AIR IS BEGINNING TO WORK INTO THE
CENTRAL TO EASTERN ALEUTIANS AS AN OCCLUDED FRONT EXTENDING EAST FROM
THE LOW WORKS NORTHWARD...ALLOWING RAIN TO MIX IN OVER SOME AREAS.

THE LOW SOUTH OF ADAK SLOWLY MOVES TO AROUND UNALASKA ISLAND ON
SUNDAY. ANOTHER LOW MOVES TO JUST EAST OF KODIAK TOMORROW AFTERNOON
AND TO NEAR SEWARD SATURDAY NIGHT.

.MODEL DISCUSSION...
MODELS ARE IN OKAY AGREEMENT THROUGH THE SHORT TERM. THERE HAS BEEN
SOME DISAGREEMENT AND RUN TO RUN INCONSISTENCY WITH THE LOW TO MOVE
NORTH THROUGH THE WESTERN GULF TOMORROW AND TOMORROW EVENING...BUT
MODELS ARE BEGINNING TO CONVERGE ON A PATH TO JUST EAST OF KODIAK
THEN NORTH TO AROUND SEWARD. MODEL AGREEMENT IS VERY POOR FROM SUNDAY
ONWARD ESPECIALLY ON THE EAST SIDE...AND CHANGES TO THE FORECAST WILL
BE MINOR FROM SUNDAY ONWARD.

.SHORT TERM FORECAST...
SOUTHCENTRAL...
SNOW SHOWERS AND WINDS CONTINUE TO SUBSIDE OVER SOUTHCENTRAL AS THE
LOW PRESSURE DISSIPATES AND A RIDGE OF HIGH PRESSURE BUILDS IN. MUCH
COLDER TEMPERATURES HAVE MOVED INTO THE REGION. THE COLD HIGH
PRESSURE WILL BE VERY SHORTLIVED...WITH ANOTHER WARM MOIST GULF LOW
MOVING NORTH THROUGH THE WESTERN GULF. THIS LOW WILL BRING SNOW LATE
TONIGHT TO KODIAK...CHANGING TO RAIN SATURDAY. SNOW WILL BEGIN LATE
TONIGHT OR TOMORROW MORNING ALONG THE NORTH GULF COAST...BUT LIKE
KODIAK...SNOW WILL CHANGE TO RAIN OVER MANY IMMEDIATE COASTAL AREAS
SATURDAY AFTERNOON AND NIGHT. NO STRONG COLD ADVECTION WILL BE
PRESENT ON THE BACKSIDE OF THIS SYSTEM...SO DO NOT EXPECT ANY
SIGNIFICANT SNOWFALL FROM THE WESTERN KENAI NORTHEAST TO THE MAT
VALLEY. THIS COULD CHANGE...HOWEVER...IF THE LOW TAKES A MORE
EASTERLY TRACK INTO PRINCE WILLIAM SOUND. WESTERN SUSITNA VALLEY
COULD SEE SIGNIFICANT SNOW AGAIN. AFTER THE LOW DISSIPATES SATURDAY
NIGHT INTO SUNDAY MORNING...MODELS ARE IN POOR AGREEMENT ON THE
DETAILS...BUT MILD MOIST SOUTHERLY FLOW IS LIKELY TO CONTINUE.

SOUTHWEST MAINLAND...
HIGH PRESSURE THIS AFTERNOON WILL BE SHORTLIVED AS AN OCCLUDED FRONT
MOVES NORTH INTO THE AREA...BRINGING SNOW LATE TONIGHT THROUGH
SATURDAY NIGHT ALONG WITH LOCALLY GUSTY WINDS AND WARMER
TEMPERATURES. THE FRONT WILL BE WEAKENING AND DOWNSLOPE SOUTHEASTERLY
FLOW WILL BE PRESENT...KEEPING SNOW AMOUNTS FROM BEING TOO
SIGNIFICANT. UNSETTLED SOUTHEAST FLOW AND MILD TEMPERATURES ARE
LIKELY TO CONTINUE THROUGH EARLY NEXT WEEK.

BERING SEA AND ALEUTIANS...
STRONG LOW PRESSURE SOUTH OF ADAK WITH AN OCCLUDED FRONT STRETCHING
EAST FROM THE LOW AND MOVING NORTH. BLIZZARD CONDITIONS ARE A CONCERN
ON THE NORTH SIDE OF THE OCCLUDED FRONT. HAVE ALREADY ISSUED A
BLIZZARD WARNING TONIGHT INTO SATURDAY MORNING FOR THE PRIBILOFS AS
THE OCCLUDED FRONT MOVES NORTH INTO THE SOUTHERN BERING. THE LOW
SLOWLY MOVES TO AROUND UNALASKA ISLAND ON SUNDAY AND INTO THE
SOUTHERN BERING SUNDAY NIGHT. UNSETTLED CONDITIONS WILL PERSIST
AROUND THE LOW...WITH RAIN AND SNOW FROM THE LOW EASTWARD...AND SNOW
SHOWERS WEST OF THE LOW.

.LONG TERM FORECAST...
MODELS NOT IN GREAT AGREEMENT IN THE LONG TERM...BUT THERE IS SOME
HINT OF A BLOCKING HIGH SETTING BACK UP IN THE EASTERN BERING...WITH
LOW PRESSURE OVER THE GULF OF ALASKA AND THE WESTERN BERING.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 185 AND 195.
MARINE...STORM WARNING ZONE 120.
         GALE WARNING ZONES 125 130 132 138 140 141 150 155 160 165
          170 172 175 176 179 351 352 411 412 413 414.
         HEAVY FREEZING SPRAY WARNING ZONES 130 140 141 165 179 185
          412 414.
FIRE WEATHER...

FOISY FEB 08