772 
 WTPZ44 KNHC 220248
 TCDEP4
  
 HURRICANE DORA DISCUSSION NUMBER  15
 NWS NATIONAL HURRICANE CENTER MIAMI FL       EP042011
 800 PM PDT THU JUL 21 2011
  
 A FEW HOURS AGO...THE EYE OF DORA ABRUPTLY DISAPPEARED ON
 GEOSTATIONARY SATELLITE IMAGES AND DEEP CONVECTION BECAME MUCH LESS
 SYMMETRIC ABOUT THE CENTER.  THIS INDICATES A SIGNIFICANT WEAKENING
 OF THE HURRICANE.  DVORAK T-NUMBERS AND CURRENT INTENSITY NUMBERS
 ARE 5.5 AND 6.5 RESPECTIVELY FROM BOTH TAFB AND SAB.  USING A BLEND
 OF THESE NUMBERS GIVES A RATHER UNCERTAIN WIND SPEED ESTIMATE OF
 110 KT.  THE HURRICANE IS BEGINNING TO CROSS THE SST GRADIENT AND
 IS HEADING FOR COOLER WATERS...ALTHOUGH IT IS CURRENTLY OVER WATERS
 OF ABOUT 28 DEGREES CELSIUS.  SOME OF THE WEAKENING IS LIKELY DUE
 TO STRONG NORTHERLY SHEAR OVER THE CYCLONE.  AN EVEN MORE RAPID
 WEAKENING IS LIKELY TO COMMENCE AS SOON AS DORA TRAVERSES MUCH
 COOLER WATERS.  THE OFFICIAL INTENSITY FORECAST IS FAIRLY CLOSE TO
 THE LATEST STATISTICAL-DYNAMICAL...LGEM...GUIDANCE.
 
 THE INITIAL MOTION...315/8...IS ONLY SLIGHTLY TO THE RIGHT OF THE
 EARLIER ESTIMATES.  DORA IS BEING STEERED BY A MID-LEVEL RIDGE OVER
 NORTHWESTERN MEXICO...AND THIS REGIME IS LIKELY TO PERSIST FOR THE
 NEXT FEW DAYS.  THE OFFICIAL FORECAST HAS BEEN ADJUSTED SOMEWHAT TO
 THE RIGHT OF THE PREVIOUS FORECAST AND IS CLOSE TO THE LATEST
 DYNAMICAL MODEL CONSENSUS.  THIS RATHER SMALL SHIFT IN THE NHC
 TRACK NOW TAKES DORA NEAR ENOUGH TO THE SOUTHERN BAJA CALIFORNIA
 PENINSULA TO BRING TROPICAL STORM FORCE WINDS TO THAT AREA. 
 CONSEQUENTLY..THE TROPICAL STORM WATCH HAS BEEN CHANGED TO A
 TROPICAL STORM WARNING FOR EXTREME SOUTHERN BAJA CALIFORNIA.
 
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  22/0300Z 18.3N 108.1W  110 KT 125 MPH
  12H  22/1200Z 19.0N 109.0W  100 KT 115 MPH
  24H  23/0000Z 20.0N 110.1W   85 KT 100 MPH
  36H  23/1200Z 21.1N 111.1W   70 KT  80 MPH
  48H  24/0000Z 22.0N 112.2W   55 KT  65 MPH
  72H  25/0000Z 24.0N 115.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
  96H  26/0000Z 26.0N 118.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 120H  27/0000Z 27.0N 120.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
  
 $$
 FORECASTER PASCH