Gale Warning 846, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AKST THU DEC 18 2008

.MODEL DISCUSSION AND UPPER LEVELS...
MODELS IN RELATIVELY GOOD AGREEMENT TODAY THROUGH WEDNESDAY MORNING.
THE ALEUTIAN LOW WILL SLIDE INTO THE GULF THIS WEEKEND WITH ANOTHER
FOLLOWING EARLY NEXT WEEK. MEANWHILE HIGH PRESSURE REMAINS OVER THE
INTERIOR. A STRONG UPPER LEVEL RIDGE WILL THEN BUILD OVER WESTERN
ALASKA WEDNESDAY THROUGH FRIDAY. THE ECMWF IS NOT AS AMPLIFIED WITH
THIS RIDGE NEXT WEEK DUE TO A STRONG LOW REMAINING IN THE CHUKCHI
SEA. THE ECMWF SCENARIO WOULD ALLOW A LONG WAVE TROUGH TO MOVE
THROUGH THE ENTIRE MAINLAND ON CHRISTMAS. WHEREAS THE GFS WOULD HAVE
SHORT WAVE TROUGH MOVING THROUGH THE MAINLAND THE DAY BEFORE
CHRISTMAS AS THE RIDGE BUILDS.

.ANALYSIS...
HIGH PRESSURE RESIDES OVER THE MAINLAND WITH A STRONG STACKED LOW IN
THE CENTRAL ALEUTIANS. A BOUNDARY OF WARMER AIR IS ALONG THE WEST
COAST OF ALASKA. THIS HAS SET UP A SCENARIO OF RAIN AND SNOW AND
FREEZING RAIN IN SOUTHWEST ALASKA. THE STRONG LOW IN THE CENTRAL
ALEUTIANS CONTINUES TO BRING STRONG NORTH WINDS ON THE BACK SIDE WITH
SNOW AND BLOWING SNOW. DECIDED TO CONTINUE THE BLIZZARD WARNING DUE
TO WINDS AND CONTINUED SNOW. WINDS SHOULD DIMINISH LATE THIS
AFTERNOON.

.SHORT TERM FORECAST...
SOUTH CENTRAL...
HIGH PRESSURE RIDGE AXIS OVER SOUTH CENTRAL. ENOUGH NORTHERLY FLOW
FOR MODERATE WINDS IN THE PRINCE WILLIAM SOUND AREA THROUGH TONIGHT.
HIGH PRESSURE TO BREAK DOWN LATE TONIGHT AND FLOW TO TURN EASTERLY.
THIS IS DUE TO A FRONT FROM THE CENTRAL ALEUTIAN LOW PUSHING FROM
KODIAK TO THE KENAI PENINSULA TONIGHT. SOUTHEAST WINDS TO INCREASE
ACROSS THE GULF AND SURROUNDING WATERS DURING THE EVENING WITH THIS
FRONT. THE PARENT LOW TO SLIDE FAR ENOUGH TO THE SOUTH THAT PRECIP
NOT TO REACH FARTHER THAN COASTAL LOCATIONS TONIGHT AND TOMORROW.
PRECIP TO WANE SATURDAY NIGHT AND SUNDAY AS THE LOW SLIDES TO THE
PACIFIC NORTHWEST.

SOUTHWEST ALASKA...
BAROCLINIC BOUNDARY ALONG THE WEST COAST WITH RAIN AND SNOW AND AREAS
OF FREEZING RAIN FROM THE COAST INTO THE KUSKOKWIM VALLEY. ABOVE
FREEZING TEMPS IN BRISTOL BAY AND THE KUSKOKWIM DELTA. HOWEVER...WARM
AIR ALOFT ENOUGH FOR POSSIBLE AREAS OF FREEZING RAIN IN THE KUSKOKWIM
VALLEY. PRECIP TO END IN THE CENTRAL AND NORTHERN KUSKOKWIM VALLEY
TONIGHT AS THE CENTRAL ALEUTIAN LOW SLIDES SOUTHEAST. RAIN AND SNOW
MIX TO REMAIN OVER COASTAL LOCATIONS INTO THE SOUTHERN KUSKOKWIM
VALLEY THROUGH TOMORROW. COLDER AIR TO FILTER IN WITH THE COLD CORE
LOW MOVING CLOSER...SO PRECIP WILL LIKELY CHANGE TO ALL SNOW FRIDAY.
PRECIP WILL BE ON THE DOWN SIDE SATURDAY AS THE LOW PULLS AWAY IN THE
GULF WITH COLDER AIR CONTINUING TO FILTER INTO SOUTHWEST ALASKA.
ANOTHER FRONT TO PUSH TO THE WEST COAST SUNDAY.

BERING AND ALEUTIANS...
A STRONG STACKED LOW JUST SOUTHEAST OF ADAK CONTINUE TO BRING STRONG
WINDS AROUND IT. ENOUGH COLD AIR AND SNOW FOR BLIZZARD CONDITIONS
OVER THE CENTRAL ALEUTIANS. THE LOW WILL BE WEAKENING TONIGHT AS IT
PUSHES SOUTHEAST WITH WINDS DIMINISHING AND ENDING THE BLIZZARD. THE
CENTRAL ALEUTIAN LOW TO PULL INTO THE GULF FRIDAY NIGHT WITH SOME
WRAP AROUND MOISTURE IN THE CENTRAL AND EASTERN ALEUTIANS. ANOTHER
STRONG FRONT TO PUSH INTO THE WESTERN ALEUTIANS WITH A PARENT LOW
NEAR KAMCHATKA PENINSULA. THIS FRONT TO PUSH THROUGH THE BERING AND
TO THE WEST COAST SUNDAY. THE PARENT LOW TO WEAKEN A SLOWLY MOVE TO
ST MATTHEW ISLAND BY SUNDAY AFTERNOON.

.LONG TERM FORECAST...
HIGH PRESSURE AND NO PRECIP TO REMAIN OVER MUCH OF SOUTH CENTRAL
SUNDAY THROUGH EARLY NEXT WEEK. A SHORT WAVE TROUGH TO MOVE THROUGH
TUESDAY NIGHT/WEDNESDAY AS A RIDGE BUILDS IN WESTERN ALASKA. A
WEAKENING LOW/BOUNDARY TO SPLIT AND SLIDE THROUGH THE EASTERN BERING
AND ALEUTIANS SUNDAY INTO MONDAY. A LOW TO TRAVERSE THE BERING MONDAY
THROUGH TUESDAY AND ONSHORE TUESDAY NIGHT WITH A FRONT REMAINING OVER
THE BERING. HIGH PRESSURE TO BUILD IN THE EASTERN BERING MID WEEK
WITH A LOW MOVING OUT OF THE NORTH PACIFIC INTO THE WESTERN ALEUTIANS
AND CROSS THE BERING THURSDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...FREEZING RAIN ADVISORY ZONE 151
MARINE...GALE 130 132 140 160 172 175 176 180
FIRE WEATHER...NONE

JN DEC 08