Blizzard in Alaska, March 18, 2008

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
402 AM ADT TUE MAR 18 2008

.ANALYSIS AND UPPER LEVELS...
BIG PICTURE IS THAT CYCLONIC FLOW DOMINATES THE STATE. UPPER LEVEL
CYCLONIC FLOW IS AND WILL REMAIN CENTERED OVER THE NORTHERN GULF OF
ALASKA OR FAR SOUTHERN MAINLAND. SURFACE LOW PRESSURE WILL PERSIST
IN THE GULF OF ALASKA. AN UPPER LEVEL JET STREAM ORIENTED WEST TO
EAST ALONG THE ALEUTIANS WILL CONTINUE TO GUIDE LOW PRESSURE SYSTEMS
ALONG OR JUST SOUTH OF THE CHAIN. THESE SYSTEMS WILL CONTINUALLY BE
ABSORBED INTO THE DOMINANT ANCHORED GULF OF ALASKA LOW. COLD
TEMPERATURES WILL CONTINUE OVER THE REGION...WITH THE COLDEST
AIRMASS BEING OVER EASTERN BERING AND SOUTHWEST MAINLAND.

THIS MORNING...WEAK SURFACE LOW PRESSURE IS PRESENT AROUND MIDDLETON
ISLAND WITH SHOWERS OVER THE GULF AND ADJACENT COASTAL AREAS...AS
WELL AS PORTIONS OF THE COPPER RIVER BASIN. A WEAK LOW NEAR
AMCHITKA IS RIDING THE ALEUTIANS WEST TO EAST AND BRINGING SNOW AND
RAIN. VERY COLD...STRONG NORTHERLY FLOW IS PRESENT OVER THE EASTERN
BERING/ALEUTIANS AND AKPEN. AN UPPER LEVEL SHORTWAVE IS BRINGING
SNOW TO THE BRISTOL BAY AREA THIS MORNING.

.MODEL DISCUSSION...
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...THEN DIGRESS A
LITTLE IN THE GULF BEGINNING THURSDAY. WE ARE USING THE GFS THURSDAY
BEYOND...ALTHOUGH ALL MODELS PAINT THE SAME GENERAL PICTURE OF AN
ANCHORED LOW IN THE GULF WITH COLD NORTHERLY FLOW OVER THE BERING.

.SHORT TERM FORECAST...
SOUTHCENTRAL...
THE WEAK SURFACE LOW NEAR MIDDLETON ISLAND THIS MORNING WILL SLOWLY
DRIFT WEST TOWARD SEWARD AND THE SOUTHERN END OF THE KENAI PENINSULA
TONIGHT THROUGH WEDNESDAY NIGHT AS COLD ADVECTION INCREASES IN THE
KODIAK ISLAND WATERS. GUSTY WEST TO NORTHWEST WINDS AND FREEZING
SPRAY WILL BE AN ISSUE THROUGH AT LEAST WEDNESDAY NIGHT FOR THE
KODIAK ISLAND WATERS AND KENNEDY ENTRANCE. SHOWER ACTIVITY WITH THE
LOW PRESSURE IS RELATIVELY MODEST...BUT WILL BE VERY PERSISTENT. THE
SHOWER ACTIVITY WILL GRADUALLY ROTATE NORTH AND INLAND TOWARD
ANCHORAGE LATER THIS AFTERNOON AND EVENING AS THE LOW DRIFTS WEST
AND OPENS MORE OF THE AREA UP TO ONSHORE FLOW. THE ONSHORE FLOW WILL
NOT BE AS WARM AS IN RECENT SYSTEMS AND MOST OF THE PRECIP WILL FALL
AS SNOW. DOWNSLOPE DRYING WILL BE LIMITED DUE TO LIGHT WINDS ALOFT
AND WEAK DYNAMICS. AM NOT EXPECTING ANYTHING HEAVY FROM THIS SYSTEM
LATER THIS AFTERNOON THROUGH THURSDAY AND POSSIBLY BEYOND...BUT IT
IS CERTAINTY SOMETHING TO WATCH ESPECIALLY CONSIDERING IT HAS BEEN
SNOWLESS FOR SO LONG OVER MUCH OF INLAND SOUTHCENTRAL.

SOUTHWEST MAINLAND...
UPPER LEVEL SHORTWAVE AND COLD NORTHWEST FLOW ARE BRINGING
PERSISTENT LIGHT SNOW TO MAINLY THE UPSLOPE AREAS OF THE SOUTHWEST
MAINLAND...MAINLY ALONG THE WEST SIDE OF THE ALEUTIAN RANGE AND
NORTHWEST SIDE OF THE KILBUCK MOUNTAINS. SOME SUBTLE CHANGES TO
OCCUR IN THE UPPER LEVELS OVER THE NEXT FEW DAYS...BUT VERY LITTLE
CHANGE IN THE LOWER LEVELS AND SENSIBLE WEATHER...WITH COLD
TEMPERATURES AND OCCASIONAL LIGHT SNOW CONTINUING.

BERING SEA/ALEUTIANS...
A WEAK LOW NEAR AMCHITKA THIS MORNING WILL RIDE JUST SOUTH OF THE
CHAIN TODAY AND THEN INTO THE GULF. ANOTHER SOMEWHAT STRONGER LOW
FOLLOWS A NEARLY IDENTICAL PATH WEDNESDAY AND WEDNESDAY NIGHT...BOTH
LOWS BRINGING MOSTLY SNOW AND SOME RAIN TO THE CENTRAL AND WESTERN
ALEUTIANS. VERY COLD AND OCCASIONALLY STRONG NORTHWEST FLOW
CONTINUES OVER THE CENTRAL/EASTERN BERING WITH PERPETUAL SNOW
SHOWERS ESPECIALLY OVER AREAS NOT COVERED BY ICE. VERY GUSTY WINDS
AT TIMES WILL CONTINUE THROUGH CHANNELED TERRAIN OF THE ALASKA
PENINSULA...AND WE WILL HOIST A BLIZZARD WATCH FOR TONIGHT AND
TOMORROW WHEN WINDS WILL INCREASE AGAIN.

.LONG TERM FORECAST...
LITTLE CHANGE IN THE PATTERN THROUGH THE EXTENDED.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WATCH ZONE 181.
MARINE...GALE WARNING ZONES 130 132 138 150 155 175 176 352 411.
         HEAVY FREEZING SPRAY WARNING ZONES 130 138 140 141 150 160
          165 179 185 412 414.
FIRE WEATHER...NONE.

FOISY MAR 08