Gale Warning 47, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
1145 AM AST TUE JAN 16 2007

.SYNOPSIS...
.SHORT RANGE...AT 18Z A DISSIPATING SURFACE LOW WAS LOCATED
AROUND 60 NM SOUTH OF PAYA WITH A TROUGH EXTENDING SOUTH OVER THE
EASTERN GULF OF ALASKA. SATELLITE AND RADAR SHOWS SCATTERED SNOW
SHOWER BANDS MOVING ONSHORE OVER THE PANHANDLE FROM THE OUTER
COASTAL WATERS. VISIBLITIES OCCASIONALLY DROP BELOW 3 MI IN THE
STRONGER SNOW SHOWERS. THE TROUGH IS EXPECTED TO MOVE THROUGH
SOUTHEAST ALASKA AND INTO NORTHWEST CANADA LATE TODAY AS A RIDGE
BUILDS IN THE GULF. SNOW SHOWERS SHOULD DIMINISH TONIGHT AS THE
TROUGH MOVES INLAND AND THE RIDGE BUILDS TO THE WEST.

THE UPPER RIDGE CONTINUES EASTWARD ON WED AS A WEAK UPPER TROUGH
MOVES INTO THE EASTERN GULF. A DEVELOPING LOW IN THE PACIFIC
MOVES NORTHEASTWARD INTO THE CENTRAL GULF WED NIGHT. THERE IS
CONSIDERABLE SPREAD WITH THE GFS AND SREF ENSEMBLES ON THE DEPTH
OF THIS LOW BUT THE OPERATIONAL GFS IS ON THE STRONGER SIDE OF
THE MEAN WHICH SEEMS MORE REASONABLE BASED ON STRENGTH OF THE
UPPER LEVEL JET MAX. GALES ARE EXPECTED OVER MOST OF THE OUTER
MARINE ZONES WED NIGHT.

PRECIPITATION ASSOCIATED WITH THE INITIAL TROUGH WILL START AS
SNOW SPREADING OVER SOUTHEAST ALASKA FROM THE WEST ON WED. AS THE
STRONGER LOW AND FRONT MOVE INTO THE GULF WED NIGHT THE SNOW WILL
MIX WITH RAIN IN COASTAL AND SOUTHERN SECTIONS.

.LONG RANGE...AMPLIFIED UPPER LEVEL PATTERN WITH LONG WAVE UPPER
RIDGE AXIS OFF WEST COAST BETWEEN 130-140W. THIS RIDGE IS FLANKED
BY COLD LONG WAVE TROUGHS OVER HUDSON BAY TO CENTRAL US AND
SIBERIA TO NW PACIFIC. EXTENDED RANGE MODELS SHOW LITTLE CHANGE
IN THIS PATTERN DURING NEXT 10 DAYS. THE PROLONGED PERIOD OF SW
FLOW ALOFT OVER THE WARM RIDGE ALONG COAST WILL RESULT IN
CONTINUED HIGH PROB OF PRECIPITATION AND ABOVE AVERAGE TEMPS INTO
NEXT WEEK.

WATER VAPOR SAT IMAGERY VALIDATES MODEL DEPICTION OF JET
ACCELERATING STRAIGHT EAST OFF ASIAN COAST 30-35N AND TURNS
TOWARD NE AFTER PASSING DATELINE. DETAILS OF INDIVIDUAL SYSTEMS
DURING DAYS 3-7 MAY FLUCTUATE SOME IN TIME DUE TO NUMBER OF WAVES
IN 160 KT PACIFIC JET. GLOBAL MODELS HAVE  DISCREPENCIES ALREADY
AT 48 HRS WITH SFC LOWS IN GULF AK ON THU MORNING. WILL STAY WITH
PREVIOUS FCSTS PREFERENCE TOWARD GFS SOLUTION WHICH HAS DEEPER
982 MB LOW EAST OF KODIAK ISLAND VS WEAKER 992 CENTER FROM WRF.
AMONG THE SERIES OF SYSTEMS HEADED TO SE AK... GFS HAS A STRONG
979 MB LOW IN THE NORTHERN GULF SUN SLINGING POTENTIALLY STRONG
WINDS AND HEAVY PCPN ACROSS THE FORECAST AREA.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...NONE
MARINE...GALE WARNING PKZ041>043-051-052-310
      ...SMALL CRAFT ADVISORY PKZ033-035-036

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