Hurricane RINA
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HURRICANE RINA DISCUSSION NUMBER 17
NWS NATIONAL HURRICANE CENTER MIAMI FL AL182011
400 AM CDT THU OCT 27 2011
RINA HAS BECOME LESS WELL ORGANIZED ON SATELLITE IMAGERY OVER THE
PAST SEVERAL HOURS...WITH THE EXTENT OF COLD CLOUD TOPS DIMINISHING
WITHIN A RAGGED-LOOKING CDO FEATURE. THIS SUGGESTS THAT SOME
WEAKENING HAS TAKEN PLACE...AND INDEED THE AIR FORCE HURRICANE
HUNTERS FOUND THAT THE CYCLONE IS NOW BARELY OF HURRICANE STRENGTH
WITH THE PEAK SFMR-OBSERVED SURFACE WINDS OF 62 KT. THE INITIAL
WIND SPEED IS SET...PERHAPS GENEROUSLY...AT 65 KT. SOUTH-
SOUTHWESTERLY SHEAR OVER RINA IS EXPECTED TO GRADUALLY INCREASE...
AND THIS ALONG WITH THE INTERACTION WITH THE YUCATAN PENINSULA AND
DRIER AIR SHOULD CAUSE THE SYSTEM TO WEAKEN THROUGHOUT THE FORECAST
PERIOD. THE OFFICIAL INTENSITY FORECAST SHOWS MORE WEAKENING THEN
THE PREVIOUS ONE FOR DAYS 1-3 AND IS THE SAME AT DAYS 4-5. THIS IS
SIMILAR TO THE STATISTICAL-DYNAMICAL DSHIPS MODEL FORECAST.
RINA IS MOVING ALONG THE WESTERN SIDE OF A MID-LEVEL HIGH PRESSURE
AREA AT ABOUT 325/5. THE TRACK GUIDANCE IS IN GENERAL AGREEMENT ON
A NORTHWARD TURN DURING THE NEXT DAY OR SO. IN 36-48 HOURS...THE
NORTHWARD MOTION IS EXPECTED TO END AS WEAK MID-LEVEL RIDGING
DEVELOPS TO THE WEST OF RINA. BY THE END OF THE FORECAST
PERIOD...THE WEAKENING CYCLONE IS LIKELY TO BE DRIVEN SOUTHWARD BY
LOW-LEVEL NORTHERLY FLOW ASSOCIATED WITH A FRONT THAT PUSHES
THROUGH THE GULF OF MEXICO. THE OFFICIAL TRACK FORECAST IS
SOMEWHAT TO THE SOUTH AND WEST OF THE PREVIOUS ONE...BUT NOT NEARLY
AS MUCH AS SHOWN BY THE PREPONDERANCE OF THE DYNAMICAL MODELS.
FORECAST POSITIONS AND MAX WINDS
INIT 27/0900Z 18.8N 86.9W 65 KT 75 MPH
12H 27/1800Z 19.8N 87.0W 60 KT 70 MPH
24H 28/0600Z 21.0N 87.1W 55 KT 65 MPH...INLAND
36H 28/1800Z 21.6N 86.8W 50 KT 60 MPH
48H 29/0600Z 21.9N 86.3W 45 KT 50 MPH
72H 30/0600Z 22.0N 85.5W 40 KT 45 MPH
96H 31/0600Z 21.5N 85.5W 35 KT 40 MPH
120H 01/0600Z 21.0N 85.5W 25 KT 30 MPH
$$
FORECASTER PASCH
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