000
WTPZ45 KNHC 141443
TCDEP5
 
TROPICAL STORM OCTAVE DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP152013
800 AM PDT MON OCT 14 2013
 
THE INITIAL MOTION ESTIMATE IS 010/11 KT. OCTAVE IS ON OR JUST NORTH
OF THE LATITUDE OF A DEEP-LAYER SUBTROPICAL RIDGE LOCATED TO ITS
EAST. AS A RESULT...A GRADUAL TURN TO THE NORTH-NORTHEAST IS
EXPECTED BY TONIGHT...FOLLOWED BY A TURN TO THE NORTHEAST ON
TUESDAY AS THE CYCLONE COMES UNDER THE INFLUENCE OF INCREASING
SOUTHWESTERLY FLOW BETWEEN THE AFOREMENTIONED RIDGE AND A BROAD
MID-/UPPER-LEVEL TROUGH SITUATED OVER THE SOUTHWESTERN UNITED
STATES. THE FORECAST TRACK WAS ADJUSTED TO THE RIGHT...BUT REMAINS
ALONG THE WESTERN EDGE OF THE TIGHTLY PACKED MODEL GUIDANCE SUITE.

OCTAVE IS MOVING OVER A NARROW TONGUE OF COLD WATER LESS THAN 24C...
AND DEEP CONVECTION HAS WEAKENED AND BECOME LESS ORGANIZED AS A
RESULT. AVERAGE SATELLITE INTENSITY ESTIMATES HAVE DECREASED TO
45-50 KT...SO THE INITIAL INTENSITY HAS BEEN LOWERED TO 50 KT.
OCTAVE IS EXPECTED TO STEADILY WEAKEN THROUGHOUT THE FORECAST
PERIOD AS IT REMAINS OVER SUB-24C SSTS AND ENCOUNTERS INCREASING
VERTICAL WIND SHEAR OF MORE THAN 30 KT BY 24 HOURS. HOWEVER...THE
CYCLONE WILL ALSO BE PASSING CLOSE ENOUGH TO A TIGHT SST GRADIENT
AND WARMER WATER JUST TO ITS EAST THAT COULD KEEP AN INFLUX OF
MOIST UNSTABLE AIR FLOWING INTO THE NORTHEAST QUADRANT...WHICH
WOULD HELP MAINTAIN CONVECTION AND TROPICAL STORM INTENSITY A
LITTLE LONGER THAN PREVIOUSLY EXPECTED. IN ADDITION...SHIP PINX-
WESTERDAM THAT HAS BEEN TRAVERSING THE SOUTHWESTERN COAST OF
BAJA THIS MORNING HAS RECENTLY REPORTED 31-KT WINDS...INDICATING
THAT OROGRAPHIC ENHANCEMENT OF THE WIND FIELD IN THE EASTERN
SEMICIRCLE IS NOW OCCURRING. GIVEN THE UNCERTAINTY IN THE EXACT
TIMING...STRENGTH...AND SIZE OF THE OUTER WINDFIELD OF OCTAVE AT
LANDFALL...A TROPICAL STORM WARNING HAS BEEN ISSUED FOR POTIONS OF
THE CENTRAL AND SOUTHWESTERN COAST OF THE BAJA CALIFORNIA PENINSULA.
EVEN IF TROPICAL STORM CONDITIONS ARE NOT OBSERVED ALONG THE
IMMEDIATE COAST...STRONGER WINDS WILL LIKELY OCCUR AT HIGHER
ELEVATIONS.
 
THE PRIMARY THREAT FROM OCTAVE WILL BE HEAVY RAINFALL AND FLASH
FLOODS AND MUDSLIDES...ESPECIALLY IN MOUNTAINOUS TERRAIN.
THEREFORE...INTERESTS ACROSS THE BAJA CALIFORNIA PENINSULA AND
MAINLAND MEXICO SHOULD MONITOR FORECASTS AND STATEMENTS ISSUED BY
THE METEOROLOGICAL SERVICE OF MEXICO.

FORECAST POSITIONS AND MAX WINDS
 
INIT  14/1500Z 22.6N 113.7W   50 KT  60 MPH
 12H  15/0000Z 24.2N 113.4W   40 KT  45 MPH
 24H  15/1200Z 25.4N 112.9W   35 KT  40 MPH
 36H  16/0000Z 26.0N 112.4W   30 KT  35 MPH...POST-TROP/REMNT LOW
 48H  16/1200Z 26.0N 112.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  17/1200Z...DISSIPATED
 
$$
FORECASTER STEWART