Tropical Depression THIRTEEN-E

ZCZC MIATCDEP3 ALL
TTAA00 KNHC DDHHMM
 
TROPICAL DEPRESSION THIRTEEN-E DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP132012
800 PM PDT FRI SEP 21 2012
 
THE WELL-DEFINED LOW PRESSURE SYSTEM LOCATED ABOUT 375 N MI
SOUTH-SOUTHWEST OF MANZANILLO MEXICO HAS ACQUIRED SUFFICIENT
CONVECTIVE ORGANIZATION TO BE CLASSIFIED AS A TROPICAL DEPRESSION.
THE INITIAL INTENSITY IS SET AT 30 KT BASED ON A BLEND OF DVORAK
CLASSIFICATIONS FROM TAFB AND SAB. THE DEPRESSION SHOULD HAVE A FEW
DAYS TO GAIN STRENGTH AS IT IS EXPECTED TO REMAIN OVER 28-29C
WATERS AND STAY IN AN FAIRLY LOW WIND SHEAR ENVIRONMENT. IN
FACT...THE SHIPS MODEL RI INDEX INDICATES ABOUT A 40 PERCENT CHANCE
OF 30-KT STRENGTHENING DURING THE NEXT 24 HOURS. AFTER A FEW
DAYS...THE GLOBAL MODELS SHOW AN INCREASE IN WESTERLY SHEAR IN
ASSOCIATION WITH AN UPPER-LEVEL TROUGH OFF THE CALIFORNIA COAST.
THESE LESS FAVORABLE ATMOSPHERIC CONDITIONS COMBINED WITH COOLER
WATERS SHOULD CAUSE A WEAKENING TREND.
 
THE DEPRESSION IS MOVING WESTWARD AT ABOUT 10 KT TO THE SOUTH OF A
MID-LEVEL RIDGE LOCATED OVER THE SOUTHWESTERN UNITED STATES. THIS
RIDGE IS EXPECTED TO WEAKEN AND BE REPLACED BY A SHORTWAVE TROUGH
IN A FEW DAYS...CAUSING THE CYCLONE TO SLOW DOWN AND TURN
WEST-NORTHWESTWARD. THE NHC FORECAST LIES BETWEEN THE GFS AND ECMWF
MODELS THROUGHOUT THE ENTIRE PERIOD. BASED ON THE CURRENT
MODEL GUIDANCE...THIS SYSTEM IS NOT EXPECTED TO BE A THREAT TO LAND.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/0300Z 13.7N 107.5W   30 KT  35 MPH
 12H  22/1200Z 13.9N 108.8W   35 KT  40 MPH
 24H  23/0000Z 14.3N 110.4W   45 KT  50 MPH
 36H  23/1200Z 14.9N 111.8W   55 KT  65 MPH
 48H  24/0000Z 15.7N 113.1W   60 KT  70 MPH
 72H  25/0000Z 17.5N 116.0W   75 KT  85 MPH
 96H  26/0000Z 18.5N 118.0W   70 KT  80 MPH
120H  27/0000Z 19.5N 120.0W   65 KT  75 MPH
 
$$
FORECASTER CANGIALOSI
 
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