000
WTPZ41 KNHC 291459
TCDEP1
TROPICAL STORM AGATHA DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP012010
800 AM PDT SAT MAY 29 2010
 
SATELLITE IMAGERY THIS MORNING CONTINUES TO SHOW INCREASED
CONVECTIVE ORGANIZATION.  THAT...COMBINED WITH 35-KT WIND VECTORS
NOTED IN AN EARLIER ASCAT OVERPASS...IS THE BASIS ON WHICH THE
DEPRESSION HAS BEEN UPGRADED TO TROPICAL STORM AGATHA. ALTHOUGH THE
CONVECTIVE CLOUD PATTERN IS ELONGATED SLIGHTLY NORTHEAST-
SOUTHWEST...THE UPPER-LEVEL OUTFLOW PATTERN HAS IMPROVED AND ALSO
BECOME MORE SYMMETRICAL.

THE INITIAL MOTION ESTIMATE IS 060/04 KT. THERE IS NO SIGNIFICANT
CHANGE TO THE PREVIOUS FORECAST TRACK REASONING. AGATHA IS EXPECTED
TO REMAIN EMBEDDED IN WEAK SOUTHWESTERLY FLOW ON THE WEST SIDE OF A
BROAD LOW-LATITUDE RIDGE THAT EXTENDS WESTWARD ACROSS THE
SOUTHWESTERN CARIBBEAN SEA AND INTO SOUTHEASTERN CENTRAL AMERICA.
THE MAJORITY OF THE NHC MODEL GUIDANCE...WITH THE EXCEPTION OF
HWRF...IS IN GENERAL AGREEMENT ON AN EAST-NORTHEASTWARD OR
NORTHEASTWARD MOTION TOWARD GUATEMALA FOR THE NEXT 36 HOURS. THE
OFFICIAL TRACK REMAINS A LITTLE TO THE LEFT OF THE MODEL
CONSENSUS...TVCN...DUE TO THE SHARP EASTWARD TRACK INTO THE
LOW-LATITUDE RIDGE FORECAST BY THE HWRF MODEL...A SCENARIO WHICH
HAS BEEN DISCOUNTED AT THIS TIME.
 
SINCE AGATHA WILL BE MOVING SLOWLY OVER VERY WARM SSTS OF AT LEAST
30C AND WITHIN A REGION OF LOW VERTICAL WIND SHEAR...ADDITIONAL
STRENGTHENING SEEMS REASONABLE. THE SHIPS MODEL IS INDICATING A
NEAR 40 PERCENT CHANCE OF RAPID STRENGTHENING DURING THE NEXT 24
HOURS...AND THIS POSSIBILITY WILL BE CLOSELY ASSESSED FOR THE NEXT
FORECAST PACKAGE IF THE RECENT CONVECTIVE DEVELOPMENT TREND
CONTINUES INTO THE AFTERNOON HOURS WHEN THUNDERSTORM ACTIVITY
OFTENTIMES WEAKENS.
 
DUE TO THE SLOW FORWARD SPEED AND INTERACTION WITH HIGH TERRAIN...
THE MAIN IMPACT FROM AGATHA IS EXPECTED TO BE EXTREMELY HEAVY
RAINFALL. THESE RAINS COULD PRODUCE LIFE-THREATENING FLASH FLOODS
AND MUD SLIDES OVER SOUTHEASTERN MEXICO...GUATEMALA...EL
SALVADOR...AND AS FAR INLAND AS HONDURAS.
 

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      29/1500Z 13.1N  93.2W    35 KT
 12HR VT     30/0000Z 13.4N  92.6W    45 KT
 24HR VT     30/1200Z 13.8N  91.9W    55 KT
 36HR VT     31/0000Z 14.3N  91.2W    50 KT...INLAND
 48HR VT     31/1200Z 14.6N  91.1W    30 KT...DISSIPATING INLAND
 72HR VT     01/1200Z 15.0N  91.5W    20 KT...DISSIPATING INLAND
 96HR VT     02/1200Z...DISSIPATED
 
$$
FORECASTER STEWART