Tropical Storm AGATHA

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TROPICAL STORM AGATHA DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 AM PDT SAT MAY 22 2004

THE CLOUD PATTERN OF THE TROPICAL CYCLONE HAS CONTINUED TO BECOME
BETTER ORGANIZED.  SATELLITE IMAGES SUGGESTED TWO HOOKING
CONVECTIVE BANDS EAST AND NORTHWEST OF THE ESTIMATED
CENTER...ALTHOUGH THE CONVECTION IS NOW WEAKENING OVER THE WESTERN
PORTION OF THE CIRCULATION.  DVORAK INTENSITY ESTIMATES ARE 35 KT
FROM TAFB...SAB...AND AFWA.  THEREFORE THE SYSTEM IS UPGRADED TO
TROPICAL STORM AGATHA.  SOME ADDITIONAL STRENGTHENING IS FORECAST
SINCE VERTICAL SHEAR IS EXPECTED TO REMAIN WEAK FOR THE NEXT DAY OR
SO.  LATER...COOLER WATERS AND INCREASED STABILITY SHOULD BRING
ABOUT WEAKENING.  THE CYCLONE IS LIKELY TO BE A REMNANT LOW BY THE
END OF THE FORECAST PERIOD. 

THE CENTER IS NOT EASY TO LOCATE...AND THE BEST GUESS FOR INITIAL
MOTION IS 300/8.  DYNAMICAL GUIDANCE INDICATES THAT THE MID-LEVEL
RIDGE TO THE NORTH OF THE STORM WILL GRADUALLY WEAKEN...RESULTING
IN A COLLAPSE OF THE STEERING CURRENT OVER THE NEXT FEW DAYS. 
ACCORDINGLY...THE OFFICIAL FORECAST SHOWS LITTLE MOTION IN THE
SECOND HALF OF THE FORECAST PERIOD.  THE FORECAST TRACK FOR THIS
ADVISORY IS A LITTLE NORTH OF THE PREVIOUS NHC FORECAST...AND THE
DYNAMICAL MODEL TRACKS ARE SLIGHTLY EAST OF MY TRACK.

THE 26 DEG C SST ISOTHERM IS NEAR 18N LATITUDE.  THUS IF AGATHA
TAKES A MORE NORTHWARD COURSE THAN EXPECTED...IT WOULD PROBABLY
WEAKEN FASTER THAN SHOWN HERE.

FORECASTER PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      22/1500Z 15.9N 109.6W    35 KT
 12HR VT     23/0000Z 16.6N 110.1W    40 KT
 24HR VT     23/1200Z 17.2N 110.7W    45 KT
 36HR VT     24/0000Z 17.7N 111.2W    45 KT
 48HR VT     24/1200Z 18.0N 111.7W    40 KT
 72HR VT     25/1200Z 18.0N 112.0W    35 KT
 96HR VT     26/1200Z 18.0N 112.0W    25 KT
120HR VT     27/1200Z 18.0N 112.0W    25 KT...REMNANT LOW
 
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