793 
 WTPZ45 KNHC 030859
 TCDEP5
  
 TROPICAL STORM JOHN DISCUSSION NUMBER   3
 NWS NATIONAL HURRICANE CENTER MIAMI FL       EP102012
 200 AM PDT MON SEP 03 2012
  
 A BURST OF STRONG CONVECTION HAS DEVELOPED OVER AND SOUTHWEST OF THE
 LOW-LEVEL CENTER SINCE THE PREVIOUS ADVISORY. A 02/1730 UTC ASCAT
 OVERPASS INDICATED TROPICAL-STORM-FORCE WINDS EXISTED WITH THE
 SYSTEM IN THE NORTHEAST QUADRANT...BUT CONVECTION HAD WANED SHORTLY
 THEREAFTER. HOWEVER...BASED ON THE INCREASE IN DEEP CONVECTION NEAR
 THE CENTER OVER THE PAST 6 HOURS...ALONG WITH AN ADT ESTIMATE OF
 T2.5/35 KT...THE SYSTEM HAS BEEN UPGRADED TO TROPICAL STORM JOHN.
 MODERATE NORTH TO NORTHEASTERLY VERTICAL WIND SHEAR IS EXPECTED TO
 AFFECT THE CYCLONE THROUGHOUT THE FORECAST PERIOD. JOHN IS ALSO
 EXPECTED TO REACH SUB-24C SSTS IN ABOUT 36 HOURS. AS A RESULT...
 LITTLE OR NO STRENGTHENING SHOULD OCCUR FOR THE NEXT 48 HOURS...
 WITH STEADY WEAKENING EXPECTED AFTER THAT. THE OFFICIAL INTENSITY
 FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY...AND FOLLOWS THE
 SHIPS AND LGEM INTENSITY GUIDANCE.
 
 RECENT MICROWAVE FIXES SUGGEST THAT THE INITIAL MOTION IS 305/10.
 SINCE JOHN IS ON TRACK...THERE IS NO SIGNIFICANT CHANGE TO THE
 PREVIOUS FORECAST TRACK OR REASONING. JOHN IS EXPECTED TO MOVE
 GENERALLY NORTHWESTWARD AT A SLOWER FORWARD SPEED AROUND THE
 SOUTHWESTERN PERIPHERY OF A MID-TROPOSPHERIC RIDGE CENTERED OVER
 THE SOUTH-CENTRAL UNITED STATES DURING THE NEXT FEW DAYS. THE NHC
 TRACK FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY TRACK...AND LIES
 CLOSE TO THE MULTI-MODEL CONSENSUS. 
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  03/0900Z 19.4N 111.7W   35 KT  40 MPH
  12H  03/1800Z 20.4N 113.4W   35 KT  40 MPH
  24H  04/0600Z 21.7N 115.2W   35 KT  40 MPH
  36H  04/1800Z 22.8N 117.0W   30 KT  35 MPH
  48H  05/0600Z 23.7N 118.5W   30 KT  35 MPH
  72H  06/0600Z 25.0N 121.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
  96H  07/0600Z 26.0N 123.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 120H  08/0600Z...DISSIPATED
  
 $$
 FORECASTER STEWART