SIO: INVEST 91S

[cycloneye]

91S INVEST 210520 0000 8.0S 59.5E SHEM 15 1010

[Nancy Smar]

ABIO10 PGTW 201430
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN OCEAN
/REISSUED/201430Z-201800ZMAY2021//
RMKS/
1. NORTH INDIAN OCEAN AREA (MALAY PENINSULA WEST TO COAST OF AFRICA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY: NONE.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
2. SOUTH INDIAN OCEAN AREA (135E WEST TO COAST OF AFRICA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) AN AREA OF CONVECTION (INVEST 91S) HAS PERSISTED NEAR 9.6S
62.8E, APPROXIMATELY 589 NM WEST-SOUTHWEST OF DIEGO GARCIA. ANIMATED
ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A FULLY EXPOSED
LOW LEVEL CIRCULATION (LLC) WITH PERSISTENT CONVECTION IN THE
NORTHWESTERN PERIPHERY AND FLARING CONVECTION BEGINNING TO FORM IN
THE SOUTHEASTERN PERIPHERY. A 201225Z SSMIS 91GHZ SATELLITE IMAGE
REVEALS DEEP CONVECTION DISPLACED TO THE NORTHEAST OF THE LLC.
ANALYSIS INDICATES A MARGINAL ENVIRONNMENT FOR DEVELOPMENT
CHARACTERIZED BY WARM (29-30C) SEA SURFACE TEMPERATURES, AND
POLEWARD OUTFLOW WITH A DEVELOPING EQUATORWARD OUTFLOW CHANNEL,
OFFSET BY MODERATE TO HIGH (20-30KT) VERTICAL WIND SHEAR (VWS).
GLOBAL MODELS GENERALLY AGREE THAT INVEST 91S WILL LOSE STRENGTH AND
BECOME LESS ORGANIZED AS IT PROPAGATES EASTWARD. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1010 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS LOW.
(2) NO OTHER SUSPECT AREAS.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: ADDED AREA IN PARA 2.B.(1) AS LOW.//
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