000
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