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TROPICAL DEPRESSION SIX DISCUSSION NUMBER   4
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT WED SEP 09 1998

SATELLITE IMAGERY SHOWS THAT ALTHOUGH THE COVERAGE OF DEEP
CONVECTION HAS INCREASED TROPICAL DEPRESSION SIX IS STILL
DISORGANIZED.  THE LATEST RECONNAISSANCE DATA RECEIVED FROM THE 
AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATES THAT THE
CENTER OF TROPICAL DEPRESSION SIX REMAINS BROAD AND ILL-DEFINED. 
THE AIRCRAFT WAS FINALLY ABLE TO CLOSE OFF A CENTER BUT REPORTS AN
ACCURACY OF 45 NMI. MEANWHILE A RADAR CENTER FIX ESTIMATE FROM THE
NATIONAL WEATHER SERVICE DOPPLER RADAR IS ABOUT 100 MILES NORTHWEST
OF THE AIRCRAFT POSITION.  SO...WITH THE CONTINUED UNCERTAINTY
SURROUNDING THE EXACT CENTER LOCATION WE WILL USE THE SAME CENTER
POSITION FROM THE 06Z ADVISORY UNTIL A MORE DEFINITIVE CENTER
EMERGES.  

RECON DATA SHOWS THAT THE MINIMUM CENTRAL PRESSURE HAS DROP 1 MB AND
IS NOW 998 MB.  MEANWHILE THE STRONGEST FLIGHT-LEVEL WINDS...35-39
KNOTS...ARE 60-90 MILES NORTHEAST OF THE CENTER.  12Z BUOY AND SHIP
DATA CONTINUES TO SHOW 20 TO 30 KNOT WINDS...WITH NCDC BUOY 42002 IS
REPORTING A EAST-NORTHEAST WIND OF 22 KNOTS AND A 999.9 MB PRESSURE.

THE SYSTEM WILL BE HELD AT TROPICAL DEPRESSION STATUS...30 KNOTS...
WITH GUSTS TO 45 KNOTS.  THE INTENSITY TREND FROM THE PREVIOUS
PACKAGE WILL BE MAINTAINED WITH THE SYSTEM FORECAST TO A TROPICAL
STORM WITHIN 12 HOURS. 

THE INITIAL MOTION ESTIMATE IS STATIONARY.  THE TRACK MODEL GUIDANCE
IS VERY SIMILAR TO THE 06Z SUITE SHOWING CONSIDERABLE SCATTER
ALTHOUGH THE CONSENSUS IS STILL WEST-NORTHWEST. THE GFDL...WHICH HAS
A LEFT BIAS IN THE GULF OF MEXICO... IS THE LEFT-MOST OF ALL THE
GUIDANCE SHOWING A SOUTHWEST HEADING.  THIS SEEMS INCONSISTENT WITH
THE SYNOPTIC PATTERN OF A MID-LEVEL NORTHWEST-SOUTHEAST ORIENTED
RIDGE.  DUE TO THE UNCERTAINTY SURROUNDING THE CENTER LOCATION THE
OFFICIAL FORECAST TRACK IS ALMOST IDENTICAL TO THE PACKAGE FROM 06Z.

THIS SEEMS TO BE THE PATH OF LEAST REGRET UNTIL WE CAN GET A MORE
CLEAR-CUT CENTER POSITION AND SUBSEQUENT MOTION.  THE TROPICAL STORM
WARNINGS REMAIN UNCHANGED.

THE NATIONAL WEATHER SERVICE DOPPLER RADAR CORPUS CHRISTI RADAR 24-
HOUR RAINFALL TOTAL OF NEAR 6 INCHES BETWEEN CORPUS AND BROWNSVILLE.
AFTER COORDINATION WITH CORPUS AND BROWNSVILLE A STATEMENT WILL BE
ADDED TO THE PUBLIC ADVISORY HIGHLIGHTING POSSIBLE HEAVY RAINFALL
WITH MORE DETAILS IN THE LOCAL STATEMENT ISSUED BY CORPUS CHRISTI. 

GUINEY
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     09/1500Z 25.6N  94.7W    30 KTS
12HR VT     10/0000Z 25.9N  95.5W    35 KTS
24HR VT     10/1200Z 26.2N  96.6W    40 KTS
36HR VT     11/0000Z 26.5N  97.6W    35 KTS...INLAND
48HR VT     11/1200Z 26.8N  98.7W    25 KTS...INLAND
72HR VT     12/1200Z 26.9N 100.0W    20 KTS...INLAND
 
 
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