436 
 WTNT42 KNHC 040250
 TCDAT2
  
 TROPICAL STORM KATIA DISCUSSION NUMBER  24
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122011
 1100 PM AST SAT SEP 03 2011
  
 ONCE AGAIN TONIGHT...THERE IS AN INCREASE IN ORGANIZATION OF THE
 CLOUD PATTERN WITH THE FORMATION OF A ROUND CENTRAL DENSE OVERCAST
 AND A BETTER DEFINED OUTFLOW IN CONVENTIONAL IR IMAGES. I HAVE BEEN
 LUCKY ENOUGH TO HAVE SEVERAL MICROWAVE PASSES OVER KATIA TONIGHT. 
 THESE DATA SHOW A MUCH BETTER ORGANIZED INNER CORE STRUCTURE THAN
 IN EARLIER PASSES...BUT THE CIRCULAR RING OF CONVECTION
 REPRESENTING THE MID-LEVEL EYE FEATURE CONTINUES TO BE DISPLACED TO
 THE NORTH OF THE LOW-LEVEL CENTER DUE TO SHEAR. THIS SUGGESTS THAT
 THE CYCLONE MIGHT NOT BE AS WELL ORGANIZED AS IT SEEMS IN
 CONVENTIONAL IMAGERY.  HAVING SAID THAT...THE INITIAL INTENSITY HAS
 BEEN KEPT AT 60 KNOTS BASED ON A BLEND OF THE LATEST DVORAK
 T-NUMBERS.  AS STATED IN THE PREVIOUS ADVISORY...KATIA COULD REACH
 HURRICANE STATUS AGAIN AT ANY TIME...AND SINCE THE SHEAR SHOULD
 BEGIN TO RELAX IN ABOUT 12 TO 24 HOURS ACCORDING TO THE SHIPS
 MODEL...A GRADUAL INTENSIFICATION IS INDICATED IN THE OFFICIAL
 FORECAST.  
 
 SINCE THE OVERALL STEERING PATTERN HAS NOT CHANGED...THERE IS NOT
 TOO MUCH TO ADD TO THE DISCUSSION.  KATIA CONTINUES TO MOVE TOWARD
 THE NORTHWEST OR 305 DEGREES AT 9 KNOTS AROUND THE SOUTHERN EDGE OF
 THE SUBTROPICAL RIDGE. GUIDANCE HAS BEEN SHIFTING SLIGHTLY EASTWARD
 OR WESTWARD DEPENDING ON HOW EACH MODEL REPRESENTS THE MID-LEVEL
 TROUGH OVER THE EASTERN UNITED STATES IN EACH RUN.  IT INTERESTING
 TO NOTE THAT TONIGHT...THE GFS DEFINES THE EASTERN SIDE OF THE
 GUIDANCE ENVELOPE AND THE ECMWF THE WESTERN EDGE. THE OFFICIAL
 FORECAST IS A THE MIDDLE OF THESE TWO EXTREME SOLUTIONS. IN
 GENERAL...MODEL SOLUTIONS ARE TO KEEP KATIA ON A TRACK BETWEEN THE
 WEST-NORTHWEST AND NORTHWEST FOR THE NEXT 3 TO 4 DAYS AND THEN TURN
 THE CYCLONE MORE TO THE NORTH THEREAFTER. 
 
 NOAA BUOY 41044...LOCATED A LITTLE MORE THAN 100 N MI TO THE
 NORTHWEST OF KATIA RECENTLY REPORTED WINDS OF 33 KNOTS AND 18-FOOT
 WAVES. 
  
 
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  04/0300Z 20.3N  57.4W   60 KT  70 MPH
  12H  04/1200Z 21.0N  58.6W   65 KT  75 MPH
  24H  05/0000Z 22.3N  60.3W   65 KT  75 MPH
  36H  05/1200Z 23.5N  62.0W   70 KT  80 MPH
  48H  06/0000Z 24.5N  63.5W   75 KT  85 MPH
  72H  07/0000Z 27.0N  67.0W   85 KT 100 MPH
  96H  08/0000Z 29.1N  70.0W   90 KT 105 MPH
 120H  09/0000Z 32.0N  71.0W   85 KT 100 MPH
  
 $$
 FORECASTER AVILA