Blizzard in Alaska, February 16, 2008

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
250 PM AST SAT FEB 16 2008

.ANALYSIS AND UPPER LEVELS...
A WIDE REACHING...VERTICALLY STACKED 965 MB LOW IS CAMPED OUT IN THE
NORTH PACIFIC A LITTLE SOUTHEAST OF ATKA. SHORTWAVES WITH EMBEDDED
SURFACE LOW PRESSURE AREAS CONTINUE TO ROTATE AROUND MAINLY THE EAST
SIDE OF THE LOW. ONE SUCH LOW IS AROUND THE SOUTHERN END OF THE
KENAI PENINSULA THIS AFTERNOON...BRINGING GUSTY WINDS...BLIZZARD
CONDITIONS TO PORTIONS OF THE KENAI PENINSULA...FAIRLY
WIDESPREAD SNOW...AND RAIN TO SOME IMMEDIATE COASTAL AREAS. AN
OCCLUDED FRONT EXTENDING NORTHEAST FROM THE NORTH PACIFIC LOW IS
BRINGING BLIZZARD CONDITIONS TO THE PRIBILOFS AND KUSKOKWIM DELTA
COAST ON THE NORTH/COLD SIDE OF THE FRONT.

THE NORTHWEST GULF LOW DISSIPATES AS IT MOVES INLAND OVER ANCHORAGE
TONIGHT. THE NORTH PACIFIC LOW SLOWLY WEAKENS AS IT INCHES TOWARD
THE SOUTHERN BERING OVER THE NEXT FEW DAYS.

.MODEL DISCUSSION...
MODELS ARE INITIALIZING ABOUT THREE HOURS TOO SLOW AND TOO
WEAK WITH THE NORTHWEST GULF LOW...AND WILL CONTINUE TO ADJUST
FORECAST ACCORDINGLY. MODELS ARE OKAY THROUGH SUNDAY NIGHT BUT THEN
HAVE POOR AGREEMENT AND RUN TO RUN CONSISTENCY OVER THE GULF OF
ALASKA MONDAY ONWARD. NOT MUCH CONFIDENCE IN ANY ONE MODEL
SOLUTION...BUT TENDING TO FAVOR THE GFS. TIMING OF SHORTWAVES AND
EMBEDDED SURFACE LOWS AROUND THE EAST SIDE OF THE NORTH
PACIFIC/BERING LOW IS THE MAIN FORECAST CHALLENGE.

.SHORT TERM FORECAST...
SOUTHCENTRAL...
THE LOW NEAR THE SOUTHERN END OF THE KENAI AS OF THIS WRITING
DISSIPATES TONIGHT AS IT MOVES OVER ANCHORAGE. AT THIS POINT...DO
NOT EXPECT SIGNIFICANT SNOWFALL IN ANCHORAGE AND SURROUNDING AREAS
DUE TO THE LACK OF ANY UP-INLET FLOW COINCIDING WITH COLD ADVECTION.
THERE STILL COULD BE A FEW INCHES...THOUGH. BLIZZARD CONDITIONS IN
EASTERN TURNAGAIN ARM AND PORTAGE VALLEY SHOULD SUBSIDE AT SOME
POINT TONIGHT AS TEMPERATURES RISE AND THE WIND SLOWLY DECREASES.
SNOW AND WINDS AROUND KACHEMAK BAY SHOULD ALSO MOSTLY SHUT OFF AS
THE LOW PASSES BY THIS EVENING. VALDEZ SNOW SHOULD CONTINUE OR
INTENSIFY TONIGHT AS THE UPPER LEVEL FLOW SHIFTS FROM SOUTHEAST TO
SOUTHWEST AS THE UPPER LEVEL SHORTWAVE PASSES THROUGH. WILL HAVE TO
WATCH THE WESTERN SUSITNA VALLEY CLOSELY FOR SNOW AMOUNTS POSSIBLY
REACHING ADVISORY LEVELS.

NOT EXPECTING MUCH OF A BREAK IN THE ACTION AFTER THE FIRST LOW
PRESSURE...AS ANOTHER SHORTWAVE WITH POSSIBLY AN EMBEDDED SURFACE
LOW MOVES NORTHWEST THROUGH THE GULF AND INTO SOUTHCENTRAL. EXPECT
MILD SOUTHEAST FLOW TO PERSIST INTO EARLY NEXT WEEK.

SOUTHWEST MAINLAND...
MOIST SOUTHEAST FLOW WILL PERSIST OVER THE SOUTHWEST MAINLAND FOR
SEVERAL DAYS. DO NOT EXPECT PRECIP TO BE TOO HEAVY DUE TO DOWNSLOPE
FLOW. BLIZZARD CONDITIONS ALONG THE KUSKOKWIM DELTA COAST SHOULD
SUBSIDE TONIGHT AS THE OCCLUDED FRONT PASSES.

BERING SEA/ALEUTIANS...
A LARGE LOW PRESSURE SYSTEM SOUTHEAST OF ATKA DOMINATES THE WEATHER
PICTURE OUT WEST...WITH A WEAKENING OCCLUDED FRONT EXTENDING
NORTHEAST FROM THE LOW THROUGH THE SOUTHERN AND SOUTHEASTERN BERING.
ON THE NORTH SIDE OF THE LOW...EXPECT BLIZZARD CONDITIONS TO
CONTINUE FOR THE PRIBILOFS INTO THE EVENING AND PERHAPS ALL THROUGH
THE NIGHT. SOUTH OF THE FRONT AND EAST OF THE LOW...OVER THE EASTERN
ALEUTIANS AND ALASKA PENINSULA...MILD SOUTHERLY FLOW WILL CONTINUE
FOR THE NEXT FEW DAYS WITH RAIN AND SNOW SHOWERS. FOR THE CENTRAL
AND WESTERN ALEUTIANS AND BERING...COLD NORTHWEST FLOW WITH SNOW
SHOWERS WILL PERSIST.

.LONG TERM FORECAST...
LOW PRESSURE WILL CONTINUE THROUGH THE LATTER PART OF THE WEEK IN
THE GULF OF ALASKA...WITH PROBABLY A GRADUAL TRANSITION FROM LOW TO
HIGH PRESSURE OVER THE CENTRAL TO EASTERN BERING SEA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 125 155 195.
MARINE...STORM WARNING 120 130.
         GALE WARNING 125 129 130 132 138 140 155 160 165 172 175 179
         185 351 352 411 412 413 414.
         HEAVY FREEZING SPRAY 140 141 185 411 412 414.
FIRE WEATHER...NONE.

FOISY FEB 08