Ice Storm in Alaska, December 21, 2005

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AST WED DEC 21 2005

.DISCUSSION...
MODELS ARE IN GENERALLY GOOD AGREEMENT. PREFER THE GFS MODEL FOR BOTH
DOMAINS FOR ITS BETTER INITIALIZATION IN THE EAST AND BETTER
CONSISTENCY IN THE WEST.

AT UPPER LEVELS...
THE RIDGE OF HIGH PRESSURE OVER THE CANADIAN ROCKIES AND INTO CENTRAL
ALASKA CONTINUES TO BE ERODED FROM THE WEST BY A SERIES OF LOWS IN
THE GULF AND FROM THE NORTH BY AN ARCTIC LOW SLIDING DOWN THE
BACKSIDE OF THE RIDGE. THAT RIDGE DOES NOT SEEM TO COMPLETELY ERODE
AWAY THROUGH NEXT MIDWEEK KEEPING THE TRACK OF LOWS UP THROUGH THE
GULF INTO SOUTHCENTRAL ALASKA. AN UPPER LOW JUST SOUTH OF THE CENTRAL
ALEUTIANS IS BEING PUSHED EAST BY A RIDGE ENTERING THE ALEUTIANS
THURSDAY.

AT THE SURFACE...
A LOW IN THE NORTHERN GULF IS BRINGING RAIN AND SNOW TO MOST OF
PRINCE WILLIAM SOUND. THIS LOW IS EXPECTED TO MOVE INTO THE SOUND AND
THEN REMAIN NEARLY STATIONARY AND DISSIPATE...BUT NOT BEFORE BRINGING
SNOW MIXED WITH RAIN TO THE MATSU VALLEY...ANCHORAGE AND WESTERN
KENAI PENINSULA LATE THIS AFTERNOON OR EVENING ENDING BY THURSDAY
MORNING. THIS MORNINGS SOUNDING HAS AN INVERSION REACHING UP INTO
ABOVE FREEZING TEMPERATURES. THEREFORE SOME AREAS MAY EXPERIENCE
ISOLATED FREEZING RAIN IN ADDITION AS WELL. ACCUMULATIONS ARE NOT
EXPECTED TO BE MUCH MORE THAN LIGHT.

A SURFACE LOW SOUTH OF THE CENTRAL ALEUTIANS IS WORKING ITS WAY EAST
INTO THE GULF BY FRIDAY IN FRONT OF A SURFACE RIDGE REFLECTED FROM
ABOVE. THAT RIDGE WILL PUSH ACROSS THE ALEUTIAN CHAIN BEGINNING
THURSDAY AS A DEEP LOW SOUTH OF THE KAMCHATKA PENINSULA PUSHES EAST.
THE ASSOCIATED FRONT WILL MOVE ACROSS THE CHAIN BRINGING STORM FORCE
WINDS AND PRECIP THROUGH SATURDAY AS ANOTHER LOW SWINGS AROUND TO THE
SOUTH AND ATTAINS ITS ENERGY BEFORE MOVING INTO THE GULF JUST SOUTH
OF KODIAK ISLAND BY MONDAY NIGHT. ON TUESDAY YET ANOTHER LOW FROM OUT
WEST WILL MOVE SOUTH OF THE PREVIOUS LOW AND TAKE ITS ENERGY AWAY
BEFORE SPINNING UP THROUGH THE EASTERN ALEUTIANS BY THURSDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 120 185
      ...HEAVY FREEZING SPRAY 185
FIRE WEATHER...NONE

LR/BL DEC 05