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Tropical Storm OLAF (Text)

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TROPICAL STORM OLAF DISCUSSION NUMBER   6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP182009
200 PM PDT FRI OCT 02 2009
 
SATELLITE IMAGERY SHOWS THAT CLOUD TOPS HAVE WARMED IN ASSOCIATION
WITH OLAF OVER THE PAST FEW HOURS...AS THE SSTS OF LESS THAN 25C
ARE TAKING A TOLL ON THE CYCLONE. ALSO...THE LOW-LEVEL CIRCULATION
CENTER APPEARS TO BE DECOUPLING FROM THE MID-LEVEL CIRCULATION...
LIKELY DUE TO THE 15-20 KNOTS OF SOUTHWESTERLY SHEAR SEEN IN
ANALYSES FROM UW-CIMSS. GIVEN THE DEGRADED SATELLITE APPEARANCE...
THE INITIAL INTENSITY IS LOWERED TO 35 KT. THIS IS IN AGREEMENT WITH
DVORAK CI-NUMBERS FROM TAFB AND SAB AND A 32-KT WIND OBSERVED BY
SHIP 3FXY2 ABOUT 150 MILES NORTH OF THE CENTER AT 1800 UTC. FURTHER
WEAKENING IS EXPECTED DUE TO COOL WATERS AND THE SHEAR INCREASING TO
MORE THAN 30 KT IN 24 HOURS...AS INDICATED BY THE SHIPS MODEL. THE
OFFICIAL FORECAST IS IN CLOSE AGREEMENT WITH THE ICON INTENSITY
CONSENSUS...AND SHOWS OLAF BECOMING A REMNANT LOW BY 36 HOURS AND
DISSIPATING BY 48 HOURS...ALTHOUGH THIS COULD OCCUR SOONER.
 
THE INITIAL MOTION ESTIMATE IS 010/08...A LITTLE TO THE RIGHT OF
PREVIOUS ESTIMATES AND THE PREVIOUS FORECAST. THE MODEL GUIDANCE IS
IN GOOD AGREEMENT ON THE OVERALL TRACK SCENARIO...WITH OLAF TURNING
TOWARD THE NORTHEAST AND EAST-NORTHEAST AHEAD OF A MID-LEVEL TROUGH
APPROACHING THE CALIFORNIA COAST IN THE NEXT DAY OR SO. THE TRACK
FORECAST IS ADJUSTED TOWARD THE NEW MODEL CONSENSUS...BUT IS SLOWER
THAN MOST OF THE GUIDANCE BASED ON THE ASSUMPTION THAT THE
LOW-LEVEL CIRCULATION WILL CONTINUE TO DECOUPLE. WHAT IS LEFT OF
THE CIRCULATION SHOULD DISSIPATE OVER THE RUGGED TERRAIN OF THE
BAJA PENINSULA BY 48 HOURS.
 
RAINFALL ASSOCIATED WITH OLAF WILL SPREAD INTO CENTRAL PORTIONS OF
THE BAJA PENINSULA TONIGHT AND SATURDAY.

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      02/2100Z 23.8N 117.2W    35 KT
 12HR VT     03/0600Z 24.8N 116.7W    30 KT
 24HR VT     03/1800Z 26.0N 115.4W    25 KT
 36HR VT     04/0600Z 27.0N 113.4W    20 KT...REMNANT LOW
 48HR VT     04/1800Z...DISSIPATED
 
$$
FORECASTER BRENNAN
 
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