Tropical Storm NORA

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TROPICAL STORM NORA DISCUSSION NUMBER   7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 AM PDT FRI OCT 03 2003
 
WATER VAPOR IMAGERY DEPICTS IMPROVING OUTFLOW OVER NORA PARTICULARLY
OVER THE SOUTH SEMICIRCLE. ENHANCED INFRARED IMAGERY IS SHOWING
CONVECTIVE BAND DEVELOPMENT OVER THE SAME AREA...AND RAGGED
DEVELOPMENT OVER THE NORTH QUADRANT. DVORAK SATELLITE INTENSITY
ESTIMATES REMAIN AT 55 KT FROM SAB...45 KT FROM TAFB AND KGWC.
BECAUSE OF THE IMPROVED OUTFLOW PRESENTATION...COLDER TOPS AND THE
DEVELOPING BANDING FEATURES...THE OFFICIAL INTENSITY IS INCREASED
TO 55 KT. A 0138Z QUIKSCAT PASS WAS USED TO ADJUST THE WIND RADII.

INITIAL MOTION IS STATIONARY. NORA IS CURRENTLY SITUATED WITHIN THE
SOUTHWEST EXTENT OF A WEAK MID LEVEL RIDGE CENTERED OVER MEXICO.
THE TROPICAL CYCLONE IS FORECAST TO TURN TOWARD THE NORTHWEST OVER
THE NEXT 24 HOURS INTO A DEVELOPING WEAKNESS IN THE SUBTROPICAL
RIDGE. THIS NORTHWESTWARD MOTION IS EXPECTED TO CONTINUE DURING THE
NEXT 72 HOURS. NOGAPS MOVES THE TROPICAL CYCLONE INTO THE WEAKNESS
CONSIDERABLY FASTER THAN THE UKMET/GFDN/GFDL CONSENSUS. THE GFS
STILL REMAINS TO THE LEFT OF THE AFOREMENTIONED MODELS. BEYOND 72
HOURS...THE MODELS INDICATE ANOTHER SHORT WAVE TROUGH APPROACHING
FROM THE NORTHWEST CREATING A SLOW NORTH TO NORTHEAST TURN TOWARD
BAJA. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS
ADVISORY...AND IS CLOSE TO THE GUNS ENSEMBLE.
 
MODEL GUIDANCE SUGGESTS THAT VERTICAL SHEAR IS EXPECTED TO REMAIN
LOW FOR THE NEXT FEW DAYS. THE SHIPS AND NOW THE GFDL MODELS
INTENSIFY NORA TO A HURRICANE IN 24 AND 12 HOURS RESPECTIVELY. BOTH
MODELS INDICATE A WEAKENING TREND COMMENCING ABOUT THE 72 HOUR POINT
AS INCREASING SOUTHWESTERLY SHEAR AND COOLER SEA SURFACE TEMPS
BEGIN TO AFFECT THE TROPICAL CYCLONE. 
 
FORECASTER ROBERTS/AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      03/0900Z 15.0N 109.3W    55 KT
 12HR VT     03/1800Z 15.5N 109.7W    60 KT
 24HR VT     04/0600Z 16.2N 110.3W    65 KT
 36HR VT     04/1800Z 17.3N 111.1W    70 KT
 48HR VT     05/0600Z 18.5N 112.0W    70 KT
 72HR VT     06/0600Z 20.5N 113.5W    60 KT
 96HR VT     07/0600Z 21.5N 114.0W    50 KT
120HR VT     08/0600Z 23.0N 114.5W    30 KT
 
 
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