Blizzard in Alaska, January 15 to 16, 2007

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM AST MON JAN 15 2007

.DISCUSSION...
12Z GFS MODELS HAS INITIALIZED THE MOISTURE FIELD WITH THE NAM AND
GFS BOTH ANALYZING THE LOW POSITIONING RATHER WELL THIS MORNING.
IN THE UPPER LEVELS SYNOPTICALLY...NCEP AND EUROPEAN MODELS ARE VERY
SIMILAR. THE ONLY DIFFERENCES THROUGH FRIDAY ARE THE TIMING ON SHORT
WAVES MOVING AROUND THE TROUGH IN THE BERING SEA.

UPPER LEVELS...LOW MOVING OVER SOUTH CENTRAL ALASKA TODAY AND EXIT
INTO CANADA TOMORROW WITH A RIDGE RIDING OVER THE GULF. IN THE
MEANTIME...THE LARGE LOW TO THE SOUTH OF THE WESTERN ALEUTIAN CHAIN
TO SLOWLY MOVE INTO THE SOUTHERN BERING. THIS LOW WITH A TROUGH AXIS
FROM THE BERING STRAIT TO 40N WILL REMAIN THROUGH SATURDAY. THE BIG
PROBLEM WILL THE TIMING AND STRENGTH OF EACH SHORT WAVE TROUGH
ROUNDING THIS LOW.

SURFACE WEST OF THE ALASKA RANGE...HIGH PRESSURE OVER SOUTHWEST
ALASKA AND THE EASTERN BERING SEA WITH A LARGE LOW PRESSURE SYSTEM
CENTERED SOUTH OF ADAK. A STRONG FRONT IS ASSOCIATED WITH THIS LOW.
THE FRONT WILL CROSS THE ALEUTIAN CHAIN TONIGHT AND HEAD INTO THE
BERING. THE PRESSURE GRADIENT WILL TIGHTEN OVER THE BERING AS THE
MAIN PUSH OF THE FRONT WILL BE TOWARD THE MAINLAND. THE TIGHTENING OF
THE GRADIENT WILL INCREASE THE WIND SIGNIFICANTLY OVER THE BERING TO
THE WESTERN CAPES. A LARGE AMOUNT OF PRECIPITATION WILL ACCOMPANY
THIS FRONT AS WELL. THEREFORE...WILL ISSUE BLIZZARD WARNING FOR SAINT
PAUL AND A WATCH FOR THE WESTERN CAPES OF BRISTOL BAY. THE FRONT
REMAINS RATHER STATIONARY OVER THE BERING BUT PROGRESSES WELL INLAND.
THE FIRST FRONT IS QUICKLY FOLLOWED BY ANOTHER WEDNESDAY WITH THE
FRONT OVER THE BERING MOVING LITTLE TO THE NORTH. WINDS WILL BEGIN TO
DIMINISH A BIT WEDNESDAY  NIGHT AS THE LOW BEGINS TO FILL. THE LOW
WILL MOVE LITTLE INTO SATURDAY BUT CONTINUE TO FILL. PRECIPITATION
WILL CONTINUE TO ROUND THE LOW. THE PRECIPITATION TYPE WILL BE A BIG
QUESTION WITH THE FIRST FRONT OVER THE BRISTOL BAY AREA. BELIEVE WE
WILL CHANGE TO RAIN OVER THIS AREA FROM KING SALMON SOUTH WITH THE
PUSH FROM THE SECOND FRONT ON WEDNESDAY. HOWEVER...IT WILL REMAIN
SNOW NORTH OF KING SALMON.

SURFACE EAST OF THE ALASKA RANGE...LOW OVER THE NORTHEAST GULF SOUTH
OF CORDOVA TO PUSH INLAND NEAR YAKUTAT LATE TONIGHT. SNOW FROM THE
SOUND EAST WILL END AS THE LOW IS PUSHED EAST. A FEW FLURRIES ARE
BEING SQUEEZED OUT OF THE ATMOSPHERE THIS AFTERNOON AS THE UPPER
LEVEL LOW IS MOVING DIRECTLY OVER ANCHORAGE. THIS FEATURE WILL FOLLOW
THE SURFACE LOW TONIGHT. HIGHER PRESSURE QUICKLY REPLACES THIS
LOW...BUT IT IS SHORT LIVED AS A STRONG FRONT FROM THE ALEUTIAN LOW
PUSHES TO KODIAK TOMORROW MORNING. STRONG WINDS AND LOTS OF
PRECIPITATION WILL ACCOMPANY THIS FRONT. GOOD JET SUPPORT WITH THIS
FEATURE AS WELL AS IT MOVES ONTO THE NORTHERN GULF COAST TUESDAY
NIGHT AND NORTH OF SOUTH CENTRAL ALASKA WEDNESDAY. PRECIPITATION WILL
HIT THE UPSLOPE SIDES WITH A GOOD AMOUNT OF SNOW. THE ANCHORAGE AREA
PARTICULARLY TURNAGAIN ARM MAY EXPERIENCE SOME SOUTH WINDS WITH THE
FRONT. AS THE FRONT PASSES...THERE SHOULD BE A SHOT OF PRECIPITATION
TO HIT THE ANCHORAGE AREA. THE SAME SHOULD GO FOR THE VALDEZ AREA DUE
TO THE FLOW. ANOTHER FRONT MOVES THROUGH WEDNESDAY NIGHT WITH SIMILAR
RESULTS. HOWEVER...THE WINDS WILL BE LESS. A LOW PRESSURE CENTER
MOVES TO SOUTH OF SEWARD THURSDAY...WITH SNOW SPREADING OVER THE
AREA. IN ADDITION...WINDS WILL BE GALE FORCE WITH THIS SYSTEM
INITIALLY WEDNESDAY NIGHT AND THURSDAY. THIS LOW LIFTS THROUGH SOUTH
CENTRAL FRIDAY WITH ANOTHER LOW MOVING INTO THE GULF. THIS NEXT LOW
TO MOVE TO THE NORTHERN GULF COAST AND WEAKEN WITH LITTLE UPPER LEVEL
SUPPORT. HOWEVER...PRECIPITATION WILL BE WIDESPREAD ALONG THE COASTAL
LOCATIONS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING ZONE 195
         BLIZZARD WATCH ZONE 125 161
MARINE...STORM 179. GALES 120 130 132 138 140 150 155 165 170 171 172
175 176 185. HEAVY FREEZING SPRAY...121 129 130 140 160 185.
FIRE WEATHER...NONE

JN JAN 07