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TROPICAL STORM NARDA DISCUSSION NUMBER   2
NATIONAL WEATHER SERVICE MIAMI FL
2 PM PDT SAT OCT 20 2001
 
AT 1730 UTC BOTH TAFB AND SAB GAVE SATELLITE INTENSITY ESTIMATES OF
35 KTS AND 30 KTS RESPECTIVELY.  DEEP CONVECTION CONTINUES TO BAND 
AROUND THE CENTER AND A BURST OF DEEP CONVECTION NEAR THE CENTER 
AROUND 1630 UTC SUGGESTS THAT THE SYSTEM CONTINUES TO GET BETTER 
ORGANIZED AND IS PROBABLY GETTING STRONGER.  UPPER LEVEL OUTFLOW 
REMAINS FAVORABLE AND THE SEA SURFACE IS WARM ENOUGH. BASED UPON 
THIS...THE SYSTEM HAS BECOME TROPICAL STORM NARDA...THE FOURTEENTH 
NAMED TROPICAL CYCLONE IN THE EASTERN PACIFIC BASIN THIS YEAR.

AT 1800 UTC SHIP ELZF9 ABOUT 130 MILES SOUTH OF THE CENTER REPORTED
A NORTHWEST WIND OF ABOUT 10 KTS.  HIS PRESSURE OF 1017 MB SEEMS TO
BE A BIT HIGH.  THIS CONFIRMS THAT WE HAVE A FAIRLY BROAD
CIRCULATION.  THE INITIAL 34 KT WIND RADII WILL BE 50 NM IN ALL
QUADS.

INITIAL MOTION IS 290/15.  THE STORM CONTINUES TO MOVE ON THE SOUTH
SIDE OF A HIGH PRESSURE RIDGE LOCATED TO THE NORTH.  MODEL GUIDANCE
REMAINS ABOUT THE SAME...MAINTAINING A WEST-NORTHWEST MOTION
THROUGHOUT THE FORECAST PERIOD.  THE OFFICIAL TRACK IS SIMILAR AND
SLIGHTLY TO THE RIGHT OF THE PREVIOUS PACKAGE.

SHIPS AND THE GFDL GRADUALLY INTENSIFY THE SYSTEM TO AROUND 50 TO 55
KTS IN ABOUT 36 HOURS BUT BEGIN WEAKENING THE SYSTEM AFTER 48
HOURS...WHEN UPPER-LEVEL WESTERLIES ARE FORECAST TO BEGIN SHEARING
THE SYSTEM.  SST VALUES WILL STILL BE IN THE 26C TO 27C RANGE AT 72
HOURS WITH THIS FORECAST TRACK...SO THE SYSTEM IS WEAKENED SLOWLY.
 
FORECASTER JARVINEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     20/2100Z 11.9N 127.0W    35 KTS
12HR VT     21/0600Z 12.9N 129.0W    45 KTS
24HR VT     21/1800Z 14.1N 131.3W    50 KTS
36HR VT     22/0600Z 15.4N 133.6W    55 KTS
48HR VT     22/1800Z 16.1N 136.1W    50 KTS
72HR VT     23/1800Z 17.5N 140.0W    45 KTS
 
 
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