SIO: AWO - Moderate Tropical Storm

[Subtrop]

91S INVEST 250805 0000 6.6S 66.8E SHEM 15 0

[StormWeather]

Is now 02S for a turn of the tables.

[sasha_B]

It's been looking like a tropical cyclone on vis/LWIR satellite imagery for a while with apparent banding and sustained central convection. Good to see it designated - this is now the second TS of the '25-'26 SIO season.

[StormWeather]

It's been looking like a tropical cyclone on vis/LWIR satellite imagery for a while with apparent banding and sustained central convection. Good to see it designated - this is now the second TS of the '25-'26 SIO season.

As far as I can tell by JTWC data, the last time we had a storm in both July and August in the Southern Hemisphere was the infamous 1996-97 season.

[Subtrop]

WTIO30 FMEE 071222
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER: 2/2/20252026
1.A MODERATE TROPICAL STORM 2 (AWO)

2.A POSITION 2025/08/07 AT 1200 UTC:
WITHIN 30 NM RADIUS OF POINT 7.3 S / 60.9 E
(SEVEN DECIMAL THREE DEGREES SOUTH AND
SIXTY DECIMAL NINE DEGREES EAST)
MOVEMENT: WEST 8 KT

3.A DVORAK ANALYSIS: 2.5/2.5/W 0.5/6 H

4.A CENTRAL PRESSURE: 1000 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 35 KT
RADIUS OF MAXIMUM WINDS (RMW): 37 KM

6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 0 SE: 140 SW: 175 NW: 110
34 KT NE: 0 SE: 0 SW: 95 NW: 0

7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1010 HPA / 700 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS (WINDS RADII IN KM):
12H: 2025/08/08 00 UTC: 7.5 S / 59.4 E, VENT MAX= 035 KT, MODERATE
TROPICAL STORM
28 KT NE: 0 SE: 220 SW: 165 NW: 0
34 KT NE: 0 SE: 130 SW: 95 NW: 0

24H: 2025/08/08 12 UTC: 7.3 S / 58.1 E, VENT MAX= 025 KT, REMNANT LOW

36H: 2025/08/09 00 UTC: 6.8 S / 57.0 E, VENT MAX= 025 KT, FILLING UP

48H: 2025/08/09 12 UTC: 6.0 S / 55.5 E, VENT MAX= 020 KT, FILLING UP

60H: 2025/08/10 00 UTC: 5.1 S / 53.7 E, VENT MAX= 020 KT, DISSIPATING

2.B LONGER-RANGE OUTLOOK:
NIL

2.C ADDITIONAL INFORMATION:
OVER THE LAST 6 HOURS, THE CLOUD PATTERN HAS EVOLVED INTO A SHEARED
PATTERN WITH CONVECTIVE ACTIVITY MAINLY LOCATED AT THE SOUTHWEST EDGE
NEAR THE ESTIMATED CENTER. CONVECTIVE ACTIVITY HAS CONTINUED TO
FRAGMENT OVER THE SOUTHEASTERN PART OF THE CIRCULATION, WHILE
MAINTAINING ACTIVITY AWAY FROM THE SYSTEM IN THE NORTHEAST QUADRANT.
IN THIS CONFIGURATION, A DVORAK ANALYSIS IN DT CAN BE PERFORMED AT
2.5, GIVING ESTIMATES OF 30KT, WHICH UNDERESTIMATES THE WIND VALUES
OF 35KT OBTAINED BY THE ASCAT PASS AT 0551UTC, AT THE SYSTEM LIMIT,
ARRIVING AFTER THE PREVIOUS ANALYSIS TIME. THE LATEST GCOM-W PASS AT
0942UTC ALSO SHOWS A CLEARER STRUCTURE IN THE SOUTHWEST SECTOR
DESPITE THE WEAKENING OF CONVECTION IN THE SOUTHEAST PART. BASED ON
THIS DATA, SYSTEM 02-20252026 WAS NAMED AWO AT 10UTC BY THE MAURITIUS
METEOROLOGICAL SERVICE. AWO IS THEREFORE A MODERATE TROPICAL STORM AT
12UTC WITH MAXIMUM WINDS OF ABOUT 35KT, MAINLY IN THE SOUTHWEST
SECTOR.

IN TERMS OF THE FORECAST TRACK, THERE IS NO CHANGE: THE DOMINANT FLOW
IS DETERMINED BY THE SUBTROPICAL RIDGE LOCATED IN THE
MID-TROPOSPHERE, INDUCTING A WESTERLY TRACK ON THURSDAY. WITH THE
WEAKENING OF THE SYSTEM AND THE DIRECTING FLOW IN THE MIDDLE
TROPOSPHERE, THE TRACK IS GRADUALLY BEING DRIVEN BY THE LOWER LAYERS.
THE TRACK IS THEREFORE HEADING WEST-NORTHWEST FROM FRIDAY, THEN
NORTHWEST BEFORE DEVELOPING INTO A RESIDUAL DEPRESSION. ON THIS
TRACK, THE SYSTEM WILL PASS OVER THE SEYCHELLES ARCHIPELAGO IN A
MUCH WEAKER STATE.

CURRENTLY, ENVIRONMENTAL CONDITIONS PRESENT A SHORT WINDOW FAVORABLE
FOR INTENSIFICATION WITH WEAKENING SHEAR AND WELL-DEFINED MOIST
SUPPLY N THE LOWER LAYERS. UNDER THESE CONDITIONS, THE SYSTEM HAS
REACHED THE THRESHOLD FOR A MODERATE TROPICAL STORM BUT IS NOT
EXPECTED TO SHOW ANY SIGNIFICANT POTENTIAL FOR INTENSIFICATION BY THE
END OF THE DAY ON THURSDAY. SUBSEQUENTLY, A RAPID WEAKENING IS
EXPECTED UNDER THE EFFECT OF INCREASED NORTHWEST SHEAR FOLLOWED BY AN
INTRUSION OF DRY AIR. CONVECTIVE ACTIVITY WILL THEN BE LIMITED TO THE
SOUTHERN SECTOR, OR EVEN FAR INTO THE EASTERN SECTOR, ALLOWING THE
SYSTEM TO CIRCULATE TOWARDS THE SEYCHELLES ARCHIPELAGO AS A
DEPRESSION THAT WILL FILL IN BY SATURDAY.

ALTHOUGH HEADING TOWARDS THE SEYCHELLES ARCHIPELAGO AND PASSING CLOSE
TO THE ISLAND OF COETIVY AT LESS THAN 100KM, THIS SYSTEM DOES NOT
PRESENT A THREAT TO INHABITED LANDS DUE TO ITS FUTURE WEAKENING. NO
SIGNIFICANT IMPACT IS EXPECTED ON INHABITED LAND OVER THE NEXT 72
HOURS.