000
WTPZ44 KNHC 230238
TCDEP4
 
TROPICAL STORM DORA DISCUSSION NUMBER  19
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP042011
800 PM PDT FRI JUL 22 2011
 
A NOAA RESEARCH AIRCRAFT INVESTIGATING DORA LATE THIS AFTERNOON
FOUND THAT THE CYCLONE WAS NO LONGER A HURRICANE...WITH PEAK 850 MB
WINDS OF 69 KT AND PEAK SFMR WINDS OF 56 KT.  BASED ON THESE
DATA...THE INITIAL INTENSITY IS ESTIMATED TO BE 60 KT...WHICH ALSO
MATCHES AN AVERAGE OF THE CI INTENSITIES FROM TAFB AND SAB.  THE
AIRCRAFT DATA WERE ALSO VERY USEFUL IN DETERMINING THE EXTENT OF
TROPICAL-STORM-FORCE WINDS.  OVER THE PAST SEVERAL HOURS THE DEEP
CONVECTION HAS BEEN DECREASING IN INTENSITY AND COVERAGE AS DORA
MOVES OVER ROUGHLY 26C WATERS...AND A COMBINATION OF NORTHEASTERLY
SHEAR AND A TRACK OVER COOLER WATERS IS EXPECTED TO CONTINUE THE
WEAKENING TREND OBSERVED TODAY.  IN ANOTHER 36 HOURS OR SO DORA
SHOULD BE A REMNANT LOW OVER 22C WATERS.

THE INITIAL MOTION IS 315/7...ABOUT THE SAME AS BEFORE. THERE HAS
BEEN LITTLE CHANGE TO THE OFFICIAL FORECAST TRACK...WHICH IS IN
BEST AGREEMENT WITH THE GFS AND ECMWF MODELS.  OVER THE NEXT DAY OR
SO...MID-LEVEL RIDGING OVER MAINLAND MEXICO...AS WELL AS
UPPER-LEVEL NORTHEASTERLY FLOW OVER THE CYCLONE...WILL WORK TO
PREVENT DORA FROM APPROACHING THE BAJA PENINSULA AS LONG AS THE
STORM MAINTAINS DEEP CONVECTION AND A VERTICALLY COHERENT
CIRCULATION.  HOWEVER...SINCE THE TROPICAL-STORM-FORCE WINDS ARE
CURRENTLY PROGGED TO PASS WITHIN 60 MILES OF THE WARNING AREA...IT
SEEMS PRUDENT TO LEAVE THE WARNING IN PLACE FOR NOW.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  23/0300Z 20.4N 110.5W   60 KT  70 MPH
 12H  23/1200Z 21.1N 111.3W   50 KT  60 MPH
 24H  24/0000Z 22.1N 112.5W   35 KT  40 MPH
 36H  24/1200Z 23.2N 113.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  25/0000Z 24.5N 115.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  26/0000Z 26.0N 117.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  27/0000Z 27.0N 118.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  28/0000Z...DISSIPATED
 
$$
FORECASTER FRANKLIN