Tropical Storm AGATHA

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TROPICAL STORM AGATHA DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP012010
200 PM PDT SAT MAY 29 2010
 
ALTHOUGH VISIBLE AND INFRARED SATELLITE IMAGERY INDICATE SOME
EROSION OF THE CENTRAL CONVECTION...MICROWAVE IMAGERY INDICATES THAT
BANDING FEATURES HAVE CONTINUED TO IMPROVE EAST AND SOUTH OF THE
CENTER.  THE INITIAL INTENSITY IS INCREASED TO 40 KT BASED ON A
SATELLITE INTENSITY ESTIMATE OF 35 KT FROM BOTH TAFB AND SAB AND
THE TIGHTER BANDING FEATURES NOTED IN MICROWAVE IMAGERY.
 
THE INITIAL MOTION ESTIMATE IS 055/06 KT...WHICH MAY BE A LITTLE
SLOW. AGATHA IS EXPECTED TO CONTINUE MOVING IN A NORTHEASTWARD OR 
EAST-NORTHEASTWARD DIRECTION FOR THE NEXT 24 HOURS AS THE CYCLONE
MOVES AROUND THE WEST SIDE OF A BROAD MID-LEVEL RIDGE THAT LIES
ALONG 12N LATITUDE. LANDFALL IS EXPECTED TO OCCUR ALONG THE
GUATEMALAN COAST BY SUNDAY MORNING. AFTER LANDFALL...THE
MOUNTAINOUS TERRAIN JUST INLAND FROM THE COAST IS EXPECTED TO CAUSE
THE LOW-LEVEL CIRCULATION TO DECOUPLE FROM THE MID- TO UPPER-LEVEL
CIRCULATION...WITH THE LATTER CONTINUING NORTHEASTWARD TOWARD THE
YUCATAN PENINSULA OR THE NORTHWESTERN CARIBBEAN SEA. SIMILAR TO THE
PREVIOUS ADVISORY...THE OFFICIAL TRACK IS CLOSE TO THE MODEL
CONSENSUS...TVCN.
 
THERE IS STILL SOME ROOM FOR SLIGHT ADDITIONAL STRENGTHENING BEFORE
AGATHA MAKES LANDFALL...BUT THE WINDOW OF OPPORTUNITY IS QUICKLY
CLOSING NOW DUE TO THE FASTER FORWARD SPEED. AFTER LANDFALL...RAPID
WEAKENING OF THE SURFACE WINDS SHOULD OCCUR. HOWEVER...VERY MOIST
SOUTHWESTERLY FLOW ON THE EAST SIDE OF AGATHA WILL CONTINUE TO
SPREAD ACROSS MUCH OF GUATEMALA AND EL SALVADOR...WHICH WILL
CONTINUE THE HEAVY RAINFALL THREAT EVEN AFTER THE SYSTEM CEASES TO
EXIST AS A TROPICAL CYCLONE.
 
DUE TO THE SLOW FORWARD SPEED AND INTERACTION WITH HIGH TERRAIN...
THE MAIN IMPACT FROM AGATHA WILL 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      29/2100Z 13.9N  92.4W    40 KT
 12HR VT     30/0600Z 14.1N  91.9W    45 KT
 24HR VT     30/1800Z 14.5N  91.2W    30 KT...INLAND
 36HR VT     31/0600Z 14.9N  90.8W    25 KT...DISSIPATING INLAND
 48HR VT     31/1800Z 15.2N  90.8W    20 KT...DISSIPATING INLAND
 72HR VT     01/1800Z...DISSIPATED INLAND
 
$$
FORECASTER STEWART/KIMBERLAIN
 
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