Hurricane RICK
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HURRICANE RICK DISCUSSION NUMBER 12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP202009
200 AM PDT SUN OCT 18 2009
INFRARED SATELLITE IMAGES SHOW THAT RICK IS MAINTAINING AN EXTREMELY
WELL-DEFINED 15 N MI DIAMETER EYE EMBEDDED WITHIN VERY COLD CLOUD
TOPS. THE UPPER-TROPOSPHERIC OUTFLOW IS QUITE EXTENSIVE AS WELL.
BOTH OBJECTIVE AND SUBJECTIVE DVORAK T-NUMBERS ARE CLOSE TO 7.5
WHICH CONTINUE TO SUPPORT AN INTENSITY OF ABOUT 155 KT...I.E.
CATEGORY FIVE STRENGTH. MICROWAVE IMAGERY SUGGESTS THAT A
CONCENTRIC EYEWALL MAY BE TRYING TO FORM WHICH COULD PRESAGE AN
EYEWALL REPLACEMENT...AND POSSIBLY SOME WEAKENING. IN ANY EVENT...
RICK HAS PROBABLY REACHED ITS MAXIMUM INTENSITY AS IT WILL BE
MOVING INTO AN ENVIRONMENT THAT WILL GRADUALLY BECOME LESS
CONDUCIVE FOR STRENGTHENING. ALTHOUGH SEA SURFACE TEMPERATURES
SHOULD BECOME ONLY SLIGHTLY COOLER ALONG THE TRACK OF RICK...GLOBAL
MODEL FORECASTS INDICATE A GRADUAL INCREASE IN VERTICAL SHEAR. THE
SHIPS MODEL SHOWS SOUTHWESTERLY SHEAR OF 20-30 KT IN ITS 3-5 DAY
PREDICTION. THE OFFICIAL INTENSITY FORECAST IS BETWEEN THE SHIPS
AND LGEM GUIDANCE THROUGH 48 HOURS AND SOMEWHAT ABOVE THOSE MODELS
AND THE INTENSITY MODEL CONSENSUS THEREAFTER...TO ALLOW FOR THE
POSSIBILITY THAT THE HURRICANE WILL NOT BE AFFECTED SO MUCH BY THE
SHEAR.
THE INITIAL MOTION...285/12...CONTINUES ABOUT THE SAME AS BEFORE.
THERE ARE NO IMPORTANT CHANGES TO THE TRACK FORECAST SCENARIO.
RICK IS BEING STEERED BY THE FLOW TO THE SOUTH OF A WEAKENING
SUBTROPICAL RIDGE. A BREAK IN THE RIDGE...ASSOCIATED WITH A
MID-TROPOSPHERIC TROUGH MOVING OVER CALIFORNIA IN A DAY OR
TWO...SHOULD CAUSE THE HURRICANE TO GRADUALLY TURN TOWARD THE NORTH
OVER THE NEXT 48-72 HOURS. AFTERWARDS...THE TRACK MODELS ARE IN
REASONABLY GOOD AGREEMENT THAT RICK WILL TURN NORTH-NORTHEASTWARD
AND NORTHEASTWARD. THE U.K. MET OFFICE MODEL REMAINS THE OUTLIER
OF THE DYNAMICAL GUIDANCE IN THAT IT SHOWS LITTLE MOTION BEYOND 48
HOURS AND IS WELL TO THE SOUTHWEST OF THE MODEL CONSENSUS. THE NHC
FORECAST TRACK IS VERY SIMILAR TO THE PREVIOUS ONE...AND SHOWS A
TRACK OVER SOUTHERN BAJA AND WESTERN MAINLAND MEXICO IN THE LATTER
PART OF THE PERIOD. HOWEVER INTERESTS IN THESE AREAS SHOULD BEAR
IN MIND THAT SIGNIFICANT ERRORS IN LANDFALL LOCATION AND TIMING ARE
POSSIBLE IN THE 4- AND 5-DAY TIME FRAME.
ALTHOUGH THE HURRICANE IS NOT LIKELY TO MAINTAIN CATEGORY FIVE
STRENGTH WHEN IT APPROACHES BAJA CALIFORNIA...IT COULD STILL BE
QUITE POWERFUL BY THAT TIME. INTERESTS IN THAT AREA AND ALONG THE
SOUTHWEST COAST OF MAINLAND MEXICO SHOULD CLOSELY FOLLOW THE
PROGRESS OF THIS EXTREMELY DANGEROUS HURRICANE OVER THE NEXT
SEVERAL DAYS.
FORECAST POSITIONS AND MAX WINDS
INITIAL 18/0900Z 15.3N 107.2W 155 KT
12HR VT 18/1800Z 15.9N 109.0W 150 KT
24HR VT 19/0600Z 17.0N 110.7W 140 KT
36HR VT 19/1800Z 18.0N 111.7W 130 KT
48HR VT 20/0600Z 19.1N 112.0W 115 KT
72HR VT 21/0600Z 21.5N 111.0W 95 KT
96HR VT 22/0600Z 24.5N 109.0W 75 KT
120HR VT 23/0600Z 28.0N 104.0W 25 KT...DISSIPATING INLAND
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FORECASTER PASCH
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