Small Craft Advisory 129, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
6 AM AKST WED FEB 9 2011

.SHORT RANGE...HIGH PRESSURE OVER THE PACIFIC OFF THE COAST OF
BRITISH COLUMBIA TOWARDS THE SOUTHERN PANHANDLE. A WEAKENING
SURFACE LOW NOW OVER THE YUKON-KUSKOKWIM DELTA REGION IS CONTINUING
NORTH. A SECOND LOW APPROXIMATELY 35N/155W AT THE BASE OF AN UPPER
LEVEL TROUGH HAS A DEVELOPING FRONTAL BAND THAT WILL LIFT
NORTHEAST THROUGH FRIDAY. THE FRONT WILL MOVE TO THE SOUTHWEST
GULF BY WED NIGHT.

THERE IS A WEAK TROUGH MOVING OVER THE PANHANDLE REGION WEDNESDAY.
COULD SEE A FEW AREAS OF HEAVIER PRECIPITATION. THIS MORNING IS
SHOWING A SOME WINTRY WEATHER YET STILL HANGS ON OVER SOUTHEAST
ALASKA. A LOW LEVEL REGION OF COLD AIR HANGS ON ACROSS A LARGE
CHUNK OF THE INNER CHANNELS AND AS ARE A RESULT THE PRECIPITATION
TYPE IS SNOW. THE WARMER AIR FROM THE GULF IS EXPECTED TO PUSH
ACROSS THE PANHANDLE DURING THE DAY...CHANGING THE SNOW TO RAIN.
BY THIS EVENING EVEN THE NORTHERN LYNN CANAL AREA SHOULD BE
CONVERTED OVER TO RAIN AS WELL...EXCEPT FOR THE THE HIGHER
ELEVATIONS.

LOCALLY WINDY AND GUSTY SOUTH OVER NORTHERN LYNN CANAL INTO THE
SKAGWAY REGION. SHOULD BE DIMINISHING THROUGH THE AFTERNOON AND
EARLY EVENING TIME FRAME.

BASED ADJUSTMENTS TO TODAY'S FORECAST ON NAM SOLUTION BUT THERE
WAS FAIRLY SIMILAR TO THE OTHER OPERATIONAL MODELS THROUGH
WEDNESDAY NIGHT.
&&

.LONG TERM...
BOTH THE 09/00Z OPS MODELS AND THE NEW ENSEMBLES ARE ON TRACK AND
AGREED WELL WITH PREVIOUS SHIFT. IF THESE STAY CONSISTENT THEN
WET-WARM INTO SATURDAY THEN LOOK OUT. THE UPR TROF THAT BEGINS TO
MOVE OVR US ON SATURDAY HAS RESPECTABLE COLD AIR ALOFT FROM THE
SIBERIAN COMPLEX LOW. NEXT...A SECOND BLAST OF COLD AIR ALOFT DIGS A
SECOND UPR TROF OVR THE CENTRAL GULF SUN AS PREDICTED BY CONSENSUS.
THIS SCENARIO SET OFF BY A STRONG UPSTREAM UPR RIDGE BUILDING OVR THE
WESTERN ALEUTIANS INTO KAMCHATKA AS HAS HAPPENED QUITE A FEW TIMES
THIS SEASON. THIS COLD AIR ALOFT DIGGING FORCES US OUT OF THE WARM
AIR FOR THE PANHANDLE AT ALL LEVELS. CONFIDENCE MODERATE. BACK TO
WINTER.

.AJK WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY DUE TO SEAS PKZ041>043-051-052.
SMCR FOR WIND PKZ011>013-022-034-036.
&&

BEZENEK/JC