211 
 WTPZ43 KNHC 240242
 TCDEP3
  
 HURRICANE MIRIAM DISCUSSION NUMBER   9
 NWS NATIONAL HURRICANE CENTER MIAMI FL       EP132012
 800 PM PDT SUN SEP 23 2012
  
 MIRIAM HAS STRENGTHENED RAPIDLY DURING THE LAST 6 HOURS OR SO. AN
 EYE...WHICH HAD BEEN EVIDENT IN MICROWAVE DATA EARLIER TODAY...
 BECAME APPARENT IN GEOSTATIONARY SATELLITE IMAGES A FEW HOURS AGO.
 THE OVERALL CLOUD PATTERN IS WELL ORGANIZED WITH COLD CLOUD TOPS
 SURROUNDING THE RAGGED EYE AND BANDING FEATURES LOCATED IN ALL
 QUADRANTS. SATELLITE INTENSITY ESTIMATES HAVE INCREASED TO 4.0/65
 KT FROM TAFB...4.5/77 KT FROM SAB...AND 4.7/82 KT FROM UW-CIMSS.
 THE INITIAL WIND SPEED IS SET AT 80 KT...NEAR THE HIGH END OF THE
 ESTIMATES GIVEN THE IMPROVED SATELLITE PRESENTATION SINCE THE TIME
 OF THE DVORAK CLASSIFICATIONS.
  
 ADDITIONAL STRENGTHENING SEEMS LIKELY DURING THE NEXT DAY OR SO AS
 MIRIAM IS EXPECTED TO REMAIN OVER SEA SURFACE TEMPERATURES OF
 27-28C AND IN A FAVORABLE UPPER-LEVEL WIND PATTERN. IN 36 TO 48
 HOURS...HOWEVER...MIRIAM IS FORECAST TO BE MOVING OVER COOL WATERS
 AND IN MODERATE SOUTHWESTERLY WIND SHEAR. THESE UNFAVORABLE
 CONDITIONS SHOULD END THE STRENGTHENING TREND...AND CAUSE THE
 CYCLONE TO WEAKEN. THE NHC INTENSITY FORECAST IS HIGHER THAN THE
 PREVIOUS ONE FOR THE FIRST 36 HOURS AND THEN FALLS IN LINE WITH THE
 OLD ONE AFTER THAT.
  
 MIRIAM IS MOVING NORTHWESTWARD AT ABOUT 10 KT. THIS GENERAL HEADING
 WITH A SLIGHT REDUCTION IN FORWARD SPEED IS EXPECTED OVER THE NEXT
 24 TO 36 HOURS AS THE RIDGE TO THE NORTHEAST OF MIRIAM WEAKENS.
 AFTER THAT...A TURN TO THE NORTH AT AN EVEN SLOWER FORWARD SPEED IS
 FORECAST AS THE HURRICANE MOVES INTO A WEAKNESS CAUSED BY A TROUGH
 OVER THE WESTERN UNITED STATES. THE NHC TRACK FORECAST IS BASICALLY
 AN UPDATE OF THE PREVIOUS ONE...AND REMAINS NEAR THE RIGHT SIDE OF
 THE GUIDANCE ENVELOPE BETWEEN THE CONSENSUS AIDS TO THE WEST AND
 THE GFS AND ECMWF MODELS TO THE EAST.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  24/0300Z 16.8N 111.3W   80 KT  90 MPH
  12H  24/1200Z 17.6N 112.5W   95 KT 110 MPH
  24H  25/0000Z 18.5N 113.9W   95 KT 110 MPH
  36H  25/1200Z 19.2N 114.8W   90 KT 105 MPH
  48H  26/0000Z 19.8N 115.2W   80 KT  90 MPH
  72H  27/0000Z 21.2N 115.9W   60 KT  70 MPH
  96H  28/0000Z 22.5N 116.0W   45 KT  50 MPH
 120H  29/0000Z 24.0N 115.5W   30 KT  35 MPH
  
 $$
 FORECASTER CANGIALOSI