912 
 WTPZ45 KNHC 160837
 TCDEP5
 TROPICAL STORM RICK DISCUSSION NUMBER   3
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP202009
 200 AM PDT FRI OCT 16 2009
  
 RICK CONTINUES TO INTENSIFY QUICKLY. OVER THE PAST SEVERAL
 HOURS...DEEP CONVECTION HAS INCREASED IN INTENSITY AND COVERAGE IN
 A LARGE CURVED BAND THAT WRAPS ABOUT THREE-QUARTERS OF THE WAY
 AROUND THE CENTER. IN ADDITION...THERE ARE INDICATIONS OF A
 RAGGED EYEWALL DEVELOPING IN THE LAST FEW INFRARED IMAGES.  BASED
 ON THE IMPROVING SATELLITE PRESENTATION...THE INITIAL INTENSITY IS
 RAISED TO 55 KT IN AGREEMENT WITH A DVORAK CI-NUMBER OF 3.5 FROM
 TAFB. 
 
 ENVIRONMENTAL CONDITIONS APPEAR TO BE FAVORABLE FOR CONTINUED
 STRENGTHENING DURING THE NEXT 2 OR 3 DAYS...AS THE SHIPS MODEL
 FORECASTS SHEAR TO BE LESS THAN 10 KT AND RICK TRAVERSES WATERS
 NEAR 30C. THE HWRF SHOWS RAPID INTENSIFICATION TO A MAJOR HURRICANE
 IN 36 HOURS AND THE GFDL IS ONLY SLIGHTLY SLOWER IN BRINGING RICK
 TO MAJOR HURRICANE STATUS. USING A BLEND OF THESE DYNAMICAL MODELS
 AND THE STATISTICAL GUIDANCE...THE OFFICIAL FORECAST SHOWS RICK
 REACHING HURRICANE INTENSITY WITHIN THE NEXT 12 HOURS AND BECOMING
 A MAJOR HURRICANE IN A COUPLE OF DAYS. THEREAFTER...SOUTHERLY TO
 SOUTHWESTERLY SHEAR IS EXPECTED TO INCREASE AND WATERS COOL A
 COUPLE OF DEGREES ALONG THE FORECAST TRACK. THIS SHOULD CAUSE SOME
 WEAKENING BY DAYS 4 AND 5...AS FORECAST BY MOST OF THE GUIDANCE.
 
 RICK IS MOVING TOWARD THE WEST-NORTHWEST OR 285/8 IN RESPONSE TO A
 MID-LEVEL RIDGE SITUATED OVER MEXICO AND THE EASTERN PACIFIC. THIS
 RIDGE SHOULD CONTINUE TO STEER RICK WEST-NORTHWESTWARD OVER THE
 NEXT COUPLE OF DAYS WITH A SLIGHT INCREASE IN FORWARD SPEED...AND
 THE MODELS ARE IN GOOD AGREEMENT ON THIS SCENARIO. AT DAY 3 AND
 BEYOND...THE MODELS DIVERGE CONSIDERABLY DUE TO DIFFERENCES IN THE
 TIMING AND AMPLITUDE OF A SHORTWAVE MID-TO UPPER-LEVEL TROUGH
 MOVING INTO THE WESTERN UNITED STATES. THE REGIONAL HURRICANE
 MODELS...HWRF AND GFDL...REMAIN FARTHEST TO THE RIGHT WITH A TRACK
 TOWARD THE SOUTHERN BAJA PENINSULA BY DAY 5. HOWEVER...SEVERAL OF
 THE GLOBAL MODELS...INCLUDING THE GFS...UKMET AND NOGAPS...REMAIN
 ON THE LEFT SIDE OF THE GUIDANCE ENVELOPE AND SHOW LESS OF A
 NORTHWARD TURN...OR NONE AT ALL. OVERALL...THE MODEL CONSENSUS HAS
 SHIFTED SLIGHTLY SOUTHWARD AT THESE LATER TIME PERIODS...AND THE
 OFFICIAL FORECAST HAS BEEN NUDGED IN THAT DIRECTION. BY DAY 5...A
 SLOW NORTHWARD MOTION IS FORECAST GIVEN THE LARGE SPREAD IN THE
 GUIDANCE AT THAT TIME.
 
 THE 34-KT WIND RADIUS IN THE NORTHEASTERN QUADRANT WAS MODIFIED
 BASED ON A 40-KT WIND OBSERVATION FROM SHIP A8BZ6 LOCATED ABOUT 40
 MILES NORTHEAST OF THE CENTER AT 0600 UTC.
 
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      16/0900Z 12.5N  98.7W    55 KT
  12HR VT     16/1800Z 12.7N  99.6W    70 KT
  24HR VT     17/0600Z 13.3N 101.1W    80 KT
  36HR VT     17/1800Z 13.8N 103.2W    90 KT
  48HR VT     18/0600Z 14.4N 105.6W   100 KT
  72HR VT     19/0600Z 16.0N 110.0W   115 KT
  96HR VT     20/0600Z 18.0N 112.0W   110 KT
 120HR VT     21/0600Z 20.0N 112.5W   100 KT
  
 $$
 FORECASTER CANGIALOSI/BRENNAN
  
 

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