Storm Warning 27, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
154 PM AKDT WED SEP 23 2009

.SHORT TERM...SATELLITE AND RADAR REVEALING GALE FORCE LOW
APPROXIMATELY 100NM SOUTHWEST OF PASI ATTM. SECOND WRAP PUSHING
ONSHORE FROM SOUTHERN BARANOF ISLAND AND SOUTHWARD. MODERATE RAIN
SHIELD MOVING NORTHEAST ACROSS THE PANHANDLE AS TRANSITION TO
SHOWERS MOVING IN FROM THE SOUTHWEST. BAND OF HEAVY PRECIP
ROTATING AROUND NORTHERN STORM CENTER...NO LIGHTING NOTED NOR
ANTICIPATED AS CONVECTIVE PARAMETERS NOT FAVORABLE. MANY SITES
REPORTING IN EXCESS OF ONE HALF INCH QPF THIS MORNING. STREET
FLOODING AND PONDING OF WATER NOTED IN PAHN THIS MORNING. IFR AND
MVFR CIGS AND VISIBILITIES TRANSITIONING TO MVFR AFTER INITIAL
FROPA.

PEAK WIND OF 43KT AT PAHY AND 36KT AT PANT AT FROPA. WINDS
BEGINNING TO PICK UP AGAIN WITH SECOND PUSH ATTM. WIND ADVISORIES
CONTINUE FOR ZONES 27 AND 28 THROUGH THIS EVENING. LOW PRESSURE
SYSTEM CONTINUES TO MOVE NORTHEAST MAKING LANDFALL NEAR PASI THIS
EVENING AND WILL RAPIDLY WEAKEN AS IT MOVES THROUGH THE NORTHERN
PANHANDLE OVERNIGHT.

FOCUS TURNS TO STORM FORCE LOW WITH THE REMNANTS OF TYPHOON CHOI-
WAN MOVING INTO THE WESTERN GULF THURSDAY. STRONG FRONTAL BOUNDARY
WILL PUSH NORTHWARD TOWARD THE OUTER COAST TOMORROW EVENING. GALE
FORCE WINDS WILL DEVELOP IN OFFSHORE AND OUTSIDE WATERS. BARRIER
JET ENHANCEMENT WILL BUMP WINDS TO MINIMAL STORM FORCE IN MZ 52.
WIND ADVISORY MAY BE NEEDED FOR OUTER COAST ZONES NEAR HAND OFF
WITH LONG TERM AS FRONT APPROACHES. LIKELY POPS TRANSITION TO
CATEGORICAL FOR MOST LOCATIONS TOMORROW AFTERNOON. 6 HR QPF
AMOUNTS INCREASE FROM ONE QUARTER TO ONE HALF INCH TOMORROW
AFTERNOON.

GLOBAL MODELS WHERE IN GOOD AGREEMENT TODAY ON POSITION TRACK AND
STRENGTH OF TODAYS STORM AND WITH TOMORROWS STORM AS WELL.
CONSISTENCY WITH PREVIOUS RUNS WAS GOOD AS WELL. BLEND OF
INHERITED GRIDS WITH 12 GFS PROVIDED STRONG CONTINUITY WITH
PREVIOUS FCST AND CONTINUITY WITH WINDS ALONG BORDER WITH AFC.
FORECAST CONFIDENCE IS ABOVE AVERAGE.

 &&

.LONG TERM...MODEL RUNS THIS MORNING IN FAIR TO GOOD AGREEMENT
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. LARGER DIFFERENCES
BEGIN TO CREEP IN DURING THE MIDDLE OF NEXT WEEK. OVER THE
REMAINDER OF THIS WEEK AND THE START OF THE WEEKEND USED THE GFS
SOLUTION FOR GRID EDITS, AND TRANSITIONED INTO TOWARDS THE HPC
GUIDANCE BY NEXT WEEK. NEW HPC GUIDANCE HAD QUITE A BIT OF THE
23/00Z ECMWF SOLUTION AND THE NEW 12Z CREPT A LITTLE CLOSER TO
WHAT GFS WAS CARRYING WITH THE LATE WEEKEND EARLY NEXT WEEK LOW.

START WITH FRONTAL BAND MOVING THROUGH SOUTHEAST ALASKA THURSDAY
NIGHT WITH THE SURFACE LOW TRACKING NORTHEAST PAST KODIAK ISLAND
TO PRINCE WILLIAM SOUND FRIDAY AFTERNOON. A SECONDARY TROUGH
BEHIND THE FRONT SHOULD LIFT INTO THE NORTHEAST GULF COAST FRIDAY
MORNING AND THE COLD TROUGH ALOFT WILL MOVE OVER SOUTHEAST ALASKA
FRIDAY NIGHT.

NEXT LOW MOVES INTO THE WEST HALF OF THE GULF SATURDAY NIGHT AND
THEN EAST TO SOUTHEAST ACROSS THE GULF. A DEEP DEVELOPING LOW
MOVING INTO THE FAR WESTERN BERING SEA WILL BUILD A RIDGE OVER THE
CENTRAL PACIFIC AND WESTERN COAST OF THE STATE. EXTENDED MODEL
PERIODS SHOW THIS RIDGE BEING MOVED EASTWARD AS THE LOW OVER THE
BERING MOVE EAST TO THE PRIBILOFS BY LATE TUESDAY. SHOULD SEE
THIS LOWS FRONTAL BAND EXTEND INTO THE GULF OF ALASKA BY MIDWEEK.

EXPECT WINDY TO VERY WINDY CONDITIONS IN THE MARINE AREAS AND
LIKELY EXPOSED COASTAL AREAS THURSDAY NIGHT INTO FRIDAY. WIND
ADVISORIES ARE POSSIBLE FOR OUTER COASTAL AREAS OF PRINCE OF WALES
ISLAND AND MAYBE SOUTHERN BARANOF ISLAND THURSDAY NIGHT.

THIS SYSTEM ALSO TROPICAL IN NATURE AS IT HAS THE REMNANTS OF THE
EX-TYPHOON IN IT. SHOULD SEE SOME FAIRLY GOOD PRECIPITATION
AMOUNTS WITHIN IT. FOR THE MOST PART RIVERS AND STREAMS ARE DOWN
BUT WILL BE KEEPING AN EYE ON THE HIGHER LEVEL ONES AND MONITOR
POTENTIAL FOR LAND/MUD SLIDES.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WIND ADVISORY UNTIL 9 PM AKDT THIS EVENING FOR AKZ027-028.
MARINE...STORM WARNING FOR PKZ036-052.
         GALE WARNING FOR PKZ035-041>043-051.
         SMALL CRAFT ADVISORY FOR PKZ011-012-021-022-031>034.

&&

CCC/BEZENEK