Hurricane NORA

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HURRICANE NORA DISCUSSION NUMBER  15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 AM PDT SUN OCT 05 2003
 
THE EYE IS NO LONGER DISCERNIBLE IN IR SATELLITE IMAGERY. 
HOWEVER...A 0459 UTC SSMI MICROWAVE DATA DETECTED A SMALL EYE THAT
WAS OPEN TO THE NORTHWEST.  DVORAK DATA T-NUMBERS HAVE BEGUN TO
DECREASE EVEN THOUGH THE CURRENT INTENSITIES ESTIMATES REMAIN
UNCHANGED DUE TO DVORAK CONSTRAINTS.  BASED ON THE LOWER DATA
T-NUMBERS...THE INITIAL INTENSITY WILL BE LOWERED SLIGHTLY TO 85
KT.  

THE TRACK FORECAST HAS BECOME SOMEWHAT COMPLICATED.  THE GLOBAL
MODELS SHOW A SIMILAR EVOLUTION OF THE SYNOPTIC PATTERN OVER THE
NEXT FEW DAYS.  THE MODELS AGREE THAT THE TROUGH SEEN CURRENTLY IN
WATER VAPOR IMAGERY OFF THE COAST OF NORTH-CENTRAL CALIFORNIA WILL
CUT-OFF AND DROP SOUTHWARD TO JUST WEST OF THE NORTHERN BAJA 
COAST IN 48 TO 72 HOURS.  

WHAT THE MODELS DO NOT AGREE ON IS THE FUTURE TRACK OF NORA. THE 
GFS INITIALIZED A MUCH WEAKER SYSTEM WHICH MOVES NORTHWEST...THEN 
IS PULLED EASTWARD TOWARD THE CIRCULATION OF TROPICAL STORM OLAF. 
THE UKMET AND NOGAPS ALSO INDICATE SOME INTERACTION BETWEEN THE
TROPICAL CYCLONES WITH NORA MOVING NORTH THEN ABRUPTLY
EAST-NORTHEAST AROUND OLAF. THE GFDL SEEMS REASONABLE IN MOVING
NORA NORTHWARD THEN NORTHEAST TOWARD BAJA BUT IS VERY SLOW.  GIVEN
THE FORECAST AMPLITUDE OF THE TROUGH ALONG THE BAJA PENINSULA...ONE
WOULD ASSUME THAT THE NORA SHOULD MOVE NORTH THEN NORTHEASTWARD
AHEAD OF THE TROUGH.  THE OFFICIAL FORECAST FOLLOWS THIS PHILOSOPHY
AND MOVES NORA A LITTLE FASTER AND TO THE RIGHT OF THE PREVIOUS
TRACK. THE FORECAST TRACK ASSUMES THAT THERE WILL BE LITTLE
INTERACTION BETWEEN NORA AND OLAF.

SHIPS GUIDANCE GRADUALLY WEAKENS NORA DURING THE NEXT 48 HOURS.
ON DAYS 3 THROUGH 5 WEAKENING SHOULD OCCUR MUCH FASTER DUE TO
INCREASING VERTICAL SHEAR AND COOLER SSTS.
 
FORECASTER BROWN/JARVINEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      05/0900Z 18.8N 113.2W    85 KT
 12HR VT     05/1800Z 19.5N 113.7W    80 KT
 24HR VT     06/0600Z 20.4N 114.0W    75 KT
 36HR VT     06/1800Z 21.1N 114.0W    70 KT
 48HR VT     07/0600Z 22.0N 114.0W    60 KT
 72HR VT     08/0600Z 23.5N 113.5W    45 KT
 96HR VT     09/0600Z 25.0N 113.0W    40 KT
120HR VT     10/0600Z 27.0N 112.0W    25 KT...INLAND
 
 
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