Hurricane KATIA

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HURRICANE KATIA DISCUSSION NUMBER  26
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122011
1100 AM AST SUN SEP 04 2011
 
EARLIER THIS MORNING...THE CENTER OF KATIA MOVED JUST TO THE SOUTH
OF NOAA BUOY 41044...WHICH MEASURED A PEAK 1-MINUTE WIND OF 78
KT...A GUST TO 93 KT...AND A MINIMUM PRESSURE OF 968.3 MB.
SUBJECTIVE DVORAK INTENSITY ESTIMATES HAVE RISEN TO BETWEEN 65 AND
77 KT FROM TAFB AND SAB...BUT THE LATEST UW-CIMSS ADT ESTIMATES
HAVE BEEN HOVERING AROUND 85 KT.  BASED ON THESE DATA...KATIA IS
INITIALIZED AS AN 85-KT HURRICANE.  AN EYE IS BECOMING APPARENT IN
VISIBLE SATELLITE IMAGERY...YET THE INFRARED IMAGERY DOES NOT SHOW
THE DEEP CONVECTION VERY SYMMETRICAL.
 
KATIA APPEARS TO BE ON TRACK WITH AN INITIAL MOTION OF 305/10 KT.
ALTHOUGH A LOT OF UNCERTAINTY REMAINS IN THE 3 TO 5 DAY FORECAST
PERIOD...LITTLE CHANGE WAS MADE ON THIS FORECAST RELATIVE TO THE
PREVIOUS ONE.  THE ECMWF...UKMET...AND HWRF MODELS REMAIN ON THE
SOUTHWESTERN SIDE OF THE GUIDANCE WHILE THE GFS AND GFDL ARE A
LITTLE FASTER AND FARTHER NORTH BY DAY 5.  MUCH OF THIS DIFFERENCE
APPEARS TO BE DUE TO THE POSITIONING OF THE CLOSED MID- TO
UPPER-LEVEL LOW FORECAST TO DEVELOP OVER THE EASTERN UNITED STATES
IN 4-5 DAYS...WHICH THE GFS SHOWS ABOUT 300 N MI FARTHER TO THE
EAST AND DEEPER THAN IN THE ECMWF AND UKMET AT DAY 5.  THE OFFICIAL
FORECAST IS VERY CLOSE TO THE MULTI-MODEL CONSENSUS AND STILL KEEPS
THE HURRICANE AT OR EAST OF 72W.
 
DESPITE THE QUICK STRENGTHENING OVER THE PAST 6 TO 12 HOURS...ADT
ESTIMATES HAVE LEVELED OFF AT 85 KT...AND IT IS HARD TO TELL IF THE
CYCLE OF RAPID INTENSIFICATION IS GOING TO CONTINUE DURING THE DAY.
THE SHIPS MODEL IS STILL DIAGNOSING ABOUT 15 KT OF SOUTH TO
SOUTHWESTERLY VERTICAL SHEAR OVER KATIA...BUT THE HURRICANE MAY BE
BENEFITING FROM UPPER-LEVEL DIVERGENCE ASSOCIATED WITH OUTFLOW
JETS TO ITS NORTH AND NORTHEAST.  THE OFFICIAL INTENSITY FORECAST
IS AT THE HIGHER RANGE OF THE INTENSITY GUIDANCE...FOLLOWING CLOSE
TO THE GFDL AND HWRF MODELS.  HOWEVER...THE ENVIRONMENT APPEARS
SUFFICIENTLY CONDUCIVE FOR INTENSIFICATION...AND KATIA COULD STILL
STRENGTHEN MORE THAN INDICATED HERE.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  04/1500Z 21.9N  59.2W   85 KT 100 MPH
 12H  05/0000Z 22.9N  60.6W   95 KT 110 MPH
 24H  05/1200Z 24.1N  62.4W  100 KT 115 MPH
 36H  06/0000Z 25.2N  64.0W  100 KT 115 MPH
 48H  06/1200Z 26.2N  65.6W  105 KT 120 MPH
 72H  07/1200Z 28.0N  68.5W  105 KT 120 MPH
 96H  08/1200Z 30.0N  71.5W  105 KT 120 MPH
120H  09/1200Z 33.0N  72.0W   95 KT 110 MPH
 
$$
FORECASTER BERG
 
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