WTPZ42 KNHC 152037 RRA

TCDEP2



TROPICAL STORM TARA DISCUSSION NUMBER   6

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP222018

400 PM CDT MON OCT 15 2018



TARA IS NOW A TINY TROPICAL STORM CONSISTING OF A SMALL, CIRCULAR

AREA OF INTENSE CONVECTION THAT CONTINUES TO GO THROUGH BURSTING

PHASES. TWO RECENT ASCAT SCATTEROMETER PASSES REVEALED THAT THE

PERSISTENT COLD OVERSHOOTING CLOUD TOPS OF -85C TO -90C NEAR THE

CENTER HAS APPARENTLY STRETCHED THE VORTEX COLUMN VERTICALLY,

CAUSING THE INTENSITY TO INCREASE AND WIND FIELD TO SHRINK. THE

34-KT WIND RADII HAVE CONTRACTED DOWN TO ABOUT 20 NMI, AND THE

OUTERMOST CIRCULATION HAS DECREASED TO ONLY ABOUT 140 NMI WIDE. THE

HIGHEST ASCAT WIND SPEED VALUE MEASURED WAS 40 KT ON BOTH PASSES.

HOWEVER, ACTUAL PEAK WINDS WERE LIKELY UNDERSAMPLED GIVEN THAT THEY

WERE OBSERVED AT A DISTANCE OF ONLY 10 NMI FROM THE CENTER. THE

INITIAL INTENSITY HAS BEEN INCREASED TO 45 KT BASED ON A DVORAK

SATELLITE INTENSITY ESTIMATE OF T3.0/45 KT FROM BOTH TAFB AND SAB,

AN OBJECTIVE UW-CIMSS ADT ESTIMATE OF T3.4/53 KT AND A SATCON

ESTIMATE OF 48 KT, AND THIS ESTIMATE IS PROBABLY CONSERVATIVE.



THE INITIAL MOTION ESTIMATE IS AN UNCERTAIN 305/02 KT. TARA'S

CENTER HAS LIKELY RE-DEVELOPED CLOSER TO THE STRONG CONVECTIVE

BURSTS THAT HAD BEEN OCCURING JUST NORTH OF THE PREVIOUS LOW-LEVEL

CENTER. AS SUCH, THE EXACT DIRECTION AND SPEED OF THE TINY TROPICAL

CYCLONE IS DIFFICULT TO ASCERTAIN. RECENT SCATTEROMETER AND VISIBLE

SATELLITE DATA SUGGEST THAT TARA MAY HAVE BECOME STATIONARY OR IS

MAKING A TIGHT LOOP. ALL OF THE GLOBAL AND REGIONAL MODELS NOW KEEP

THE TINY TROPICAL CYCLONE OFFSHORE FOR THE ENTIRE 120-H FORECAST