Storm Warning 23, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
358 PM AKST THU MAR 4 2010

.SHORT TERM...A WEAK TROUGH ALOFT AND AT THE SURFACE WILL BE
LIFTING ACROSS THE NORTHEAST GULF COAST THROUGH THE EVENING WITH
A BAND OF ENHANCED SHOWERS MOVING TOWARDS THE YAKUTAT REGION.
CONVECTION LOOKS AS IF IT MAY BE STRONG ENOUGH SO HAVE ADDED
MENTION OF ISOLATED THUNDERSTORM FOR MARINE AREAS 051 AND 052 FOR
THE EVENING. THE STALLED WEATHER FRONT OVER THE SOUTHERN
PANHANDLE CONTINUE TO MOVE EAST THROUGH THE AFTERNOON AND EVENING
WILL KEEPS SOME LIGHT PRECIPITATION THERE. MAINLY AND A MIX OR
RAIN THROUGH EVENING BEFORE IT TAPERS OFF.

THERE IS A PERIOD OF RIDGING THROUGH THE EVENING AND OVERNIGHT
AHEAD OF THE NEXT FRONTAL BAND. THIS FRONT WILL MOVE INTO THE
EASTERN GULF ON FRIDAY. THE FRONT IS ASSOCIATED WITH THE STRONG
UPPER 950 MB LOW SOUTHWEST OF DUTCH HARBOR AND THE LOW WILL TRACK
EAST ALONG THE ALEUTIANS AND THE ALASKA PENINSULA TO COOK INLET BY
LATE FRIDAY AFTERNOON AS A 965 MB LOW. THERE IS A PUSH OF COLDER
AIR ALOFT SO EXPECT THE MOST OF THE PRECIPITATION EARLY FRIDAY TO
BE SNOW AND THE AS THE FRONT APPROACHES SOUTHEAST ALASKA WITH SOME
WARMER AIR WILL SEE A MIX OR CHANGE OVER IN THE AFTERNOON. THINK
THE BEST SNOW FOR YAKUTAT WILL BE STARTING ABOUT 6 AM AND
CONTINUING INTO THE AFTERNOON...WITH RAIN MIXING IN AROUND 3 PM OR
SO. RIGHT NOW AM FORECASTING 2 TO 5 INCHES AND WILL BE HOLDING OFF
ON WINTER WEATHER ADVISORY. WILL HAVE THE NEXT SHIFT TAKE A CLOSER
LOOK WITH THE NEW MODEL RUNS. 850MB TEMP FOR THE 00Z RUN AT
YAKUTAT WAS -9.3C AND WILL LIKELY NEED TO WARM TO AROUND -4 BEFORE
THERE WILL BE A CHANGE OVER.

WILL SEE THE WINDS INCREASING AHEAD OF THE FRONT AS WELL...GALES
FOR THE OUTER COASTAL AREAS FROM THE SOUTH TO SOUTHEAST
FRIDAY...WITH THE EXCEPTION OF PKZ052 WHERE I THINK THERE WILL BE
ENOUGH TO GO STORM FORCE 50 KT AROUND MIDDAY. ALONG THE COASTAL
AREA THINK THAT WEST OF YAKUTAT ALONG THE COAST GUSTS WILL BE IN
EXCESS OF 40 MPH SO A WIND ADVISORY FOR WEST OF YAKUTAT WILL BE
ISSUED FOR THE FRIDAY AFTERNOON.

.LONG TERM...PROGRESSIVE PATN WITH THE GULF SEEING A SEQUENCE OF
STRONG POLAR FRONT ZONE WAVES MOVG ONSHORE THE PNHDL. THERMAL
FIELDS SHOW THE WAVES RUNNING WELL ABOVE AND BELOW FREEZING FOR
ALL OF THE FCST DOMAIN EXCEPT THE SRN PNHDL. THIS LARGE SCALE
PROGRESSIVENESS IS MORE TYPICAL OF THIS TIME OF YEAR THAN MUCH OF
WHAT HAS HAPPENED THIS WINTER.

12Z AK GFS WAS USED AS PRIMARY GUIDANCE. 12Z MON A TRANSITION WAS
MADE TO HPC GUIDANCE FOR WINDS AND SURFACE PRESSURE.

MODEL CHANGES FROM RUN TO RUN ARE LARGE FOR SUN NIGHT THROUGH
TUE, AND CONFIDENCE IS LOWER THAN USUAL FOR THESE PERIODS.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WIND ADVISORY FROM NOON TO 6 PM AKST FRIDAY FOR AKZ017.
MARINE...STORM WARNING FOR PKZ052.
         GALE WARNING FOR PKZ041>043-051.
         SMALL CRAFT ADVISORY FOR PKZ011-012-021-022-031-033>036.

&&

BEZENEK/JBT