SOUTH INDIAN: 24S(HABANA) set to re-intensify after 48hours and 25S(IMAN) analysed at 45knots, 07/21utc updates

24S(HABANA) AND 25S(IMAN). ON THE RIGHT END 24S LOST IT EYE FEATURE WHICH HAS BEEN BACK RECENTLY. 25S HAS INTENSIFIED BUT HAS A SHEARED PATTERN. CLICK TO ANIMATE IF NEEDED.

24S(HABANA).WARNING 8 ISSUED AT 07/21UTC.TC 24S HAS WEAKENED STEADILY OVER THE PAST TWELVE HOURS, AND TEMPORARILY LOST ITS EYE, UNDER THE INFLUENCE OF A SHORT-TERM INCREASE IN VERTICAL WIND SHEAR AND COOLING OCEAN WATER BENEATH THE SLOW-MOVING SYSTEM. TC 24S IS TURNING POLEWARD UNDER THE INFLUENCE OF A SHIFTING STEERING PATTERN, WITH SUBTROPICAL RIDGING BUILDING TO THE EAST. VERTICAL WIND HAS EASED A BIT OVER THE PAST SIX HOURS (10- 15 KTS), SEA SURFACE TEMPERATURES ARE MODERATELY FAVORABLE (26-28C) AND STRONG POLEWARD OUTFLOW IS EVIDENT IN SATELLITE-DERIVED, UPPER- LEVEL WIND VECTOR DATA. TC 24S IS EXPECTED TO TURN WESTWARD OVER THE NEXT 24 TO 36 HOURS AS SUBTROPICAL RIDGING BUILDS TO THE SOUTH AND TAKES OVER AS THE DOMINANT STEERING MECHANISM. THE SYSTEM WILL CONTINUE FOLLOWING THE FLOW ASSOCIATED WITH THIS RIDGE, TURNING POLEWARD BY 120H. FURTHER NEAR-TERM WEAKENING IS EXPECTED BEFORE PASSAGE OVER WARM WATER, ROBUST OUTFLOW AND LOW VERTICAL WIND SHEAR DRIVE A DISTINCT INTENSIFICATION TREND WITH POSSIBLE RAPID INTENSIFICATION AFTER 36H.

24S(HABANA). WITH THE EXCEPTION OF THE NAVGEM TRACK, WHICH LIES SLIGHTLY TO THE SOUTH OF THE ENVELOPE, AND THE ECMWF ENSEMBLE MEAN, WHICH LIES SLIGHTLY TO THE NORTH OF THE MODEL ENVELOPE, NUMERICAL MODEL GUIDANCE IS IN VERY GOOD AGREEMENT, LENDING HIGH CONFIDENCE TO THE CURRENT JTWC FORECAST TRACK.

24S(HABANA). 07/2045UTC. THE EYE FEATURE IS CLEARLY APPARENT ONCE AGAIN SINCE 07/2015UTC.

24S(HABANA). 07/1637UTC. THE CURRENT POSITION IS SITUATED NEAR A LOW-LEVEL CENTER FEATURE EVIDENT IN A 071637Z METOP-C ASCAT PASS.

24S(HABANA). CIMSS Vertical Shear Magnitude : 6.6 m/s (12.8 kts) Direction : 34.4 deg CIMSS Experimental Vertical Shear and TC Intensity Trend Estimates: NEUTRAL OVER 24H

25S(IMAN). NUMERICAL MODEL GUIDANCE IS IN EXCELLENT AGREEMENT REGARDING THE FORECAST TRACK, WHICH IS PLACED NEAR THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE.

25S(IMAN). WARNING 1 ISSUED AT 07/21UTC.25S(IMAN) HAS CONSOLIDATED AND INTENSIFIED OVER THE PAST SIX HOURS WHILE TRACKING EAST-SOUTHEASTWARD IN THE GRADIENT BETWEEN SUBTROPICAL RIDGING TO THE NORTHEAST AND AN APPROACHING, DEEP-LAYER TROUGH TO THE SOUTHWEST. THE SYSTEM IS EXPECTED TO CONTINUE TRACKING GENERALLY SOUTHEASTWARD OVER THE NEXT 36 HOURS AND COMPLETE EXTRATROPICAL TRANSITION AS THE APPROACHING TROUGH OVERTAKES THE SYSTEM. WHILE POLEWARD OUTFLOW IS STRONG AND SEA SURFACE TEMPERATURE IS MARGINALLY FAVORABLE AT AROUND 27C, VERTICAL WIND SHEAR IS VERY HIGH (GREATER THAN 30 KNOTS). THE CONTINUED IMPACT OF STRONG VERTICAL WIND SHEAR AND PASSAGE OVER COOL WATER ARE EXPECTED TO WEAKEN THE SYSTEM THROUGHOUT THE FORECAST PERIOD, WITH NO OFFSETTING BAROCLINIC SUPPORT FROM INTERACTION WITH THE AFOREMENTIONED TROUGH.

25S(IMAN). 07/2015UTC.

25S(IMAN). THE CURRENT POSITION AND INTENSITY ARE BASED ON A 071724Z METOP-B ASCAT PASS WHICH READ 45KNOT WINDS.

07/21UTC. JTWC IS ISSUING 12HOURLY WARNINGS ON 24S(HABANA) AND 25S(IMAN). 3HOURLY SATELLITE BULLETINS ARE ISSUED FOR BOTH SYSTEMS. THEY WERE DISCONTINUED FOR 23P(NIRAN) AND 22S(MARIAN).