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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