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TROPICAL STORM NARDA DISCUSSION NUMBER   3
NATIONAL WEATHER SERVICE MIAMI FL
8 PM PDT SAT OCT 20 2001

CONVECTION ASSOCIATED WITH NARDA IS CONSOLIDATING THIS EVENING...
WITH A CENTRAL DENSE OVERCAST OF TOPS COLDER THAN -80C DEVELOPING
OVER THE LOW LEVEL CENTER.  SATELLITE INTENSITY ESTIMATES...WHICH
INCLUDE DVORAK CONSTRAINTS...ARE 35 KT FROM TAFB...SAB...AND AFWA.
THE INITIAL INTENSITY WILL BE INCREASED TO 40 KT BASED ON THE 
ESTIMATES AND THE INCREASE IN ORGANIZATION SINCE 00Z.

THE INITIAL MOTION IS 295/13.  SATELLITE IMAGERY INDICATES THAT
NARDA IS ON THE SOUTH SIDE OF A DEEP LAYER RIDGE...AND THAT A LARGE
MID/UPPER LEVEL TROUGH IS PRESENT TO THE EAST AND NORTHEAST OF THE
HAWAIIAN ISLANDS.  LARGE-SCALE MODELS INDICATE THAT THE MID-LEVEL
PORTION OF THE TROUGH WILL WEAKEN AND ALLOW RIDGING TO BUILD 
WESTWARD.  THIS PATTERN SHOULD MOVE NARDA ALONG A WEST-NORTHWEST TO
POSSIBLY WEST TRACK.  NHC HURRICANE GUIDANCE IS SOMEWHAT SPREAD...
WITH THE GFDL...UKMET AND BAMS FAVORING A WEST-NORTHWEST MOTION AND
BAMD...BAMM..AND LBAR FAVORING A SLOWER AND MORE NORTHWEST MOTION. 
GIVEN THE INITIAL MOTION...THE FORECAST TRACK WILL GO WITH THE
GFDL...UKMET...BAMS SOLUTION AND WILL BE AN UPDATE OF THE PREVIOUS
FORECAST.

NARDA IS SHOWING GOOD ANTICYCLONIC OUTFLOW...ESPECIALLY TO THE WEST
WHERE FOR THE MOMENT IT SEEMS TO BE REPELLING ONCOMING UPPER-LEVEL
WESTERLIES.  BASED ON THIS AND THE INCREASED CENTRAL CONVECTION...
THE SHORT-TERM INTENSITY FORECAST WILL BE RAISED A LITTLE.  IN THE
LONG-TERM...LARGE-SCALE MODELS FORECAST THAT THE WEAKENING OF THE
CENTRAL PACIFIC TROUGH SHOULD CREATE INCREASING UPPER-LEVEL
WESTERLY FLOW ACROSS THE PATH OF NARDA AFTER 36 HR...WHICH SHOULD
PRODUCE STRONG SHEAR.  THUS...SIGNIFICANT WEAKENING IS FORECAST 
AFTER THE 36 HR POINT.  IT IS POSSIBLE THAT DUE TO ITS SMALL SIZE
THAT NARDA COULD BOTH STRENGTHEN AND WEAKEN FASTER THAN CURRENTLY
FORECAST.

FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     21/0300Z 12.5N 128.1W    40 KTS
12HR VT     21/1200Z 13.4N 129.9W    50 KTS
24HR VT     22/0000Z 14.5N 132.0W    55 KTS
36HR VT     22/1200Z 15.5N 134.3W    60 KTS
48HR VT     23/0000Z 16.2N 136.4W    55 KTS
72HR VT     24/0000Z 17.5N 141.0W    40 KTS
 
 
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