000
WTPZ43 KNHC 092034
TCDEP3
 
TROPICAL STORM CALVIN DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP032011
200 PM PDT SAT JUL 09 2011
 
VISIBLE AND MICROWAVE SATELLITE IMAGERY SHOWS THAT CALVIN CONTINUES
TO WEAKEN QUICKLY...WITH THE CENTER NOW EXPOSED TO THE EAST OF A
DIMINISHING AREA OF CONVECTION. THE INITIAL INTENSITY IS SET AT 40
KT USING A BLEND OF DVORAK CI AND FINAL-T NUMBERS FROM TAFB AND
SAB...AND A 1745 UTC ASCAT PASS THAT SHOWED A SMALL PATCH OF 35-40
KT WINDS EAST OF THE CENTER. CONTINUED WEAKENING IS FORECAST AS THE
CYCLONE MOVES OVER EVEN COLDER WATERS AND THE OFFICIAL FORECAST
SHOWS CALVIN BECOMING A REMNANT LOW BY TOMORROW IN AGREEMENT WITH
THE SHIPS AND LGEM. DISSIPATION IS EXPECTED WITHIN 48 TO 72
HOURS...BUT COULD OCCUR SOONER.
 
THE CENTER IS LOCATED A LITTLE NORTHEAST OF PREVIOUS ESTIMATES...BUT
THE INITIAL MOTION REMAINS TOWARD THE WEST-NORTHWEST OR 285 DEGREES
AT 8 KNOTS.  AS CALVIN CONTINUES TO WEAKEN...IT WILL BE STEERED
GENERALLY WEST-NORTHWESTWARD BY THE LOW-LEVEL FLOW UNTIL
DISSIPATION.  THE NEW NHC FORECAST IS ESSENTIALLY AN UPDATE OF THE
PREVIOUS ONE AFTER ADJUSTING FOR THE INITIAL POSITION.
 
THE 34-KT WIND RADII HAVE BEEN ADJUSTED INWARD BASED ON 09/1734Z
ASCAT SCATTEROMETER DATA.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  09/2100Z 17.4N 111.7W   40 KT  45 MPH
 12H  10/0600Z 17.8N 113.0W   30 KT  35 MPH
 24H  10/1800Z 18.3N 114.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  11/0600Z 18.8N 116.2W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  11/1800Z 19.3N 117.6W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  12/1800Z...DISSIPATED
 
$$
FORECASTER BRENNAN/STEWART
 


000
WTPZ43 KNHC 092034
TCDEP3
 
TROPICAL STORM CALVIN DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP032011
200 PM PDT SAT JUL 09 2011
 
VISIBLE AND MICROWAVE SATELLITE IMAGERY SHOWS THAT CALVIN CONTINUES
TO WEAKEN QUICKLY...WITH THE CENTER NOW EXPOSED TO THE EAST OF A
DIMINISHING AREA OF CONVECTION. THE INITIAL INTENSITY IS SET AT 40
KT USING A BLEND OF DVORAK CI AND FINAL-T NUMBERS FROM TAFB AND
SAB...AND A 1745 UTC ASCAT PASS THAT SHOWED A SMALL PATCH OF 35-40
KT WINDS EAST OF THE CENTER. CONTINUED WEAKENING IS FORECAST AS THE
CYCLONE MOVES OVER EVEN COLDER WATERS AND THE OFFICIAL FORECAST
SHOWS CALVIN BECOMING A REMNANT LOW BY TOMORROW IN AGREEMENT WITH
THE SHIPS AND LGEM. DISSIPATION IS EXPECTED WITHIN 48 TO 72
HOURS...BUT COULD OCCUR SOONER.
 
THE CENTER IS LOCATED A LITTLE NORTHEAST OF PREVIOUS ESTIMATES...BUT
THE INITIAL MOTION REMAINS TOWARD THE WEST-NORTHWEST OR 285 DEGREES
AT 8 KNOTS.  AS CALVIN CONTINUES TO WEAKEN...IT WILL BE STEERED
GENERALLY WEST-NORTHWESTWARD BY THE LOW-LEVEL FLOW UNTIL
DISSIPATION.  THE NEW NHC FORECAST IS ESSENTIALLY AN UPDATE OF THE
PREVIOUS ONE AFTER ADJUSTING FOR THE INITIAL POSITION.
 
THE 34-KT WIND RADII HAVE BEEN ADJUSTED INWARD BASED ON 09/1734Z
ASCAT SCATTEROMETER DATA.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  09/2100Z 17.4N 111.7W   40 KT  45 MPH
 12H  10/0600Z 17.8N 113.0W   30 KT  35 MPH
 24H  10/1800Z 18.3N 114.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  11/0600Z 18.8N 116.2W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  11/1800Z 19.3N 117.6W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  12/1800Z...DISSIPATED
 
$$
FORECASTER BRENNAN/STEWART