[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 302043
TCDAT1

HURRICANE OPHELIA DISCUSSION NUMBER  33
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL162011
500 PM AST FRI SEP 30 2011

OPHELIA HAS MAINTAINED A DISTINCT EYE ON SATELLITE IMAGES DURING THE
DAY. THE INTENSITY OF THE CONVECTION SURROUNDING THE EYE HAS BEEN
FLUCTUATING AND THERE IS A SALIENT THUNDERSTORM BAND WRAPPING AROUND
THE NORTH AND EAST OF THE CENTRAL DENSE OVERCAST. SUBJECTIVE
T-NUMBERS HAVE NOT CHANGED WHILE THE ADT OBJECTIVE ESTIMATES FROM
UW-CIMSS HAVE BEEN NEAR 5.9 DURING THE PAST FEW HOURS. THE AVERAGE
OF THESE TWO ESTIMATES SUPPORT KEEPING THE INITIAL INTENSITY AT 100
KNOTS.

SOME INTENSITY FLUCTUATIONS ARE ANTICIPATED DURING THE NEXT DAY OR
SO WHILE OPHELIA IS OVER WARM WATERS AND EMBEDDED WITHIN A LOW
SHEAR ENVIRONMENT AS DIAGNOSED BY THE SHIPS MODELS. THEREAFTER...
THE HURRICANE SHOULD BE MOVING INTO INCREASING SHEAR AND ENCOUNTER
COLD WATERS...RESULTING IN WEAKENING. OPHELIA SHOULD BECOME A
POST-TROPICAL CYCLONE AS IT MOVES TO THE SOUTHEAST OF NEWFOUNDLAND
IN 72 HOURS AND THEN BECOME ABSORBED BY A LARGER FRONTAL SYSTEM.

OPHELIA IS MOVING TOWARD THE NORTH OR 350 DEGREES AT 12 KNOTS
EMBEDDED WITHIN THE FLOW BETWEEN THE ATLANTIC SUBTROPICAL HIGH AND
A LARGE MID-LATITUDE TROUGH OVER THE EASTERN UNITED STATES. THIS
PATTERN SHOULD FORCE OPHELIA TO CONTINUE MOVING NORTHWARD DURING
THE NEXT 24 HOURS AND THEN RECURVE WITH AN INCREASE IN FORWARD
SPEED...AS THE CORE OF THE CYCLONE PASSES EAST OF BERMUDA.
THE CONFIDENCE IN THE NHC TRACK FORECAST REMAINS HIGH SINCE THE
TRACK GUIDANCE IS TIGHTLY CLUSTERED. AS INDICATED IN PREVIOUS
ADVISORIES...THE WESTERN EDGE OF THE TRACK ENVELOPE CONTINUES TO BE
EAST OF BERMUDA.


FORECAST POSITIONS AND MAX WINDS

INIT  30/2100Z 24.7N  63.0W  100 KT 115 MPH
 12H  01/0600Z 26.5N  63.2W  100 KT 115 MPH
 24H  01/1800Z 29.8N  62.8W  100 KT 115 MPH
 36H  02/0600Z 34.0N  62.0W   90 KT 105 MPH
 48H  02/1800Z 39.0N  60.0W   85 KT 100 MPH
 72H  03/1800Z 48.0N  47.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
 96H  04/1800Z...ABSORBED BY A FRONTAL SYSTEM

$$
FORECASTER AVILA



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