ARB: INVEST 96A

[doomhaMwx]

96A INVEST 201120 1800 7.7N 56.3E IO 20 1006
96A INVEST 201120 1200 8.0N 56.2E IO 15 1010

[doomhaMwx]

ABIO10 PGTW 201800

AN AREA OF CONVECTION (INVEST 96A) HAS PERSISTED NEAR 8.0N 56.2E, APPROXIMATELY 302 NM SOUTH-SOUTHEAST OF SOCOTRA. ANIMATED ENHANCED INFRARED IMAGERY DEPICTS DISORGANIZED FLARING DEEP CONVECTION, HOWEVER A 201530Z SCATSAT PASS INDICATES A LOW LEVEL CIRCULATION CENTER (LLCC) HAS DEVELOPED ALONG THE WESTERN EXTENT OF A LARGE MONSOON TROUGH OVER THE NORTH ARABIAN SEA. THE CIMSS 850 MB VORTICITY PRODUCT ALSO INDICATES THE PRESENCE OF A DISTINCT VORTICITY CENTER IN THIS AREA. THERE IS CURRENTLY STRONG DIVERGENCE ALOFT PROVIDING GOOD OUTFLOW, HOWEVER, THIS IS PARTIALLY OFFSET BY MODERATE (15-20 KNOTS) VERTICAL WIND SHEAR. 27 DEGREE CELSIUS SEA SURFACE TEMPERATURES ARE FAVORABLE FOR FURTHER DEVELOPMENT. MODEL DEVELOPMENT IS NOT STRONGLY INDICATIVE OF TROPICAL CYCLONE FORMATION AT THIS TIME, AS INVEST 96A SPINS CYCLONICALLY AROUND THE BROADER CIRCULATION AND IS EVENTUALLY ABSORBED. 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.

[doomhaMwx]

 https://twitter.com/doomhaMwx/status/1330086670302121984

ABIO10 PGTW 210830

THE AREA OF CONVECTION (INVEST 96A) PREVIOUSLY LOCATED
NEAR 7.0N 56.1E IS NOW LOCATED NEAR 6.5N 56.5E, APPROXIMATELY 392 NM
SOUTH-SOUTHEAST OF SOCOTRA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
DEPICTS AN EXPOSED, WELL-DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC)
WITH FLARING DEEP CONVECTION SHEARED TO THE WEST. A 210621Z MHS
89GHZ MICROWAVE IMAGE INDICATES DISORGANIZED CONVECTION AND A WEAKLY-
DEFINED LLCC. A 210507Z ASCAT-A 25-KM BULLSEYE IMAGE REVEALS A
DEFINED CIRCULATION WITH 20-25 KNOT WINDS AND ISOLATED 25-30 KNOT
WINDS OVER THE NORTHWEST QUADRANT. UPPER-LEVEL ANALYSIS INDICATES A
MARGINAL ENVIRONMENT WITH 20-25 KNOT EASTERLY VERTICAL WIND SHEAR,
ASSOCIATED WITH INVEST 95A'S UPPER-LEVEL ANTICYCLONE, AND BROAD
DIFFLUENCE. INVEST 96A IS LOCATED ABOUT 316 NM SSW OF INVEST 95A AND
APPEARS TO BE UNDERGOING DIRECT CYCLONE INTERACTION (I.E., FUJIWARA)
WITH INCREASING APPROACH VELOCITIES. THE 21/00Z GFS RUN INDICATES
THAT INVEST 96A WILL CONTINUE DIRECT CYCLONE INTERACTION WITH THE
DOMINANT SYSTEM, INVEST 95A, AND WILL TRACK CYCLONICALLY AND GET
ABSORBED INTO THE EASTERN PERIPHERY OF INVEST 95A WITHIN THE NEXT 36
HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 MB.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS UPGRADED TO MEDIUM.

[doomhaMwx]

ABIO10 PGTW 220630

THE AREA OF CONVECTION (INVEST 96A) PREVIOUSLY LOCATED
NEAR 7.1N 58.0E HAS DISSIPATED AND IS NO LONGER SUSPECT FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE IN THE NEXT 24 HOURS.

[AJC3]

This sure looked like it briefly reached minimal TS strength before getting absorbed by what became VSCS Gati.

[doomhaMwx]

Indeed. While it didn't really look like much as it was sheared throughout its lifetime, ASCAT passes on 11/21 ~06Z clearly show a TC, with the Metop-B finding a few 35kt barbs underneath the deep convection.




Satellite images at that time.




Another ASCAT hit ~10hrs later shows the system was no longer a TC as it began interacting with what was soon-to-be 03A/Gati.





This is one of some probable short-lived TSs in the Arabian Sea this year that were missed by IMD (and JTWC). What's worse is that there was no mention from IMD at all about this system, not even as a LPA!

JTWC BT

96A INVEST 201122 0000 7.5N 59.1E IO 20 1007
96A INVEST 201121 1800 7.1N 58.0E IO 20 1007
96A INVEST 201121 1200 6.7N 57.1E IO 25 1004
96A INVEST 201121 0600 6.5N 56.6E IO 25 1004
96A INVEST 201121 0000 6.6N 56.1E IO 25 1004
96A INVEST 201120 1800 6.9N 55.9E IO 20 1006