INVEST 90S// INVEST 91S// ECMWF 10 Day Storm Tracks// 3 Week Tropical Cyclone Formation Probability//0809utc

JTWC IS ISSUING 3HOURLY SATELLITE BULLETINS ON INVEST 90S AND ON INVEST 91S.

THE AREA OF CONVECTION (INVEST 90S) PREVIOUSLY LOCATED NEAR 22.8S 41.4E IS NOW LOCATED NEAR 23.0S 42.0E, APPROXIMATELY 103 NM SOUTHEAST OF EUROPA ISLAND. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) AND A 071605Z SSMIS 91GHZ MICROWAVE IMAGE DEPICT A PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH FLARING CONVECTION DISPLACED TO THE NORTHEAST OF THE CIRCULATION. ENVIRONMENTAL ANALYSIS REVEALS A MARGINALLY FAVORABLE ENVIRONMENT FOR FURTHER DEVELOPMENT WITH LOW (10-15 KTS) VWS, GOOD UPPER-LEVEL OUTFLOW EQUATORWARD, AND WARM (28-30C) SEA SURFACE TEMPERATURES (SST). HOWEVER, A DEEP-LAYER DRY AIR MASS WRAPPING INTO 90S FROM THE WEST IS THE PRIMARY LIMITING FACTOR IN INTENSIFICATION. GLOBAL DETERMINISTIC MODELS ARE IN GOOD AGREEMENT THAT 90S WILL CONTINUE TO WEAKEN IN THE MOZAMBIQUE CHANNEL AS IT APPROACHES THE EAST COAST OF AFRICA OVER THE NEXT 24 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 22 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.

A DEEP-LAYER DRY AIR MASS WRAPPING INTO 90S FROM THE WEST IS THE PRIMARY LIMITING FACTOR IN INTENSIFICATION.

GLOBAL DETERMINISTIC MODELS ARE IN GOOD AGREEMENT THAT 90S WILL CONTINUE TO WEAKEN IN THE MOZAMBIQUE CHANNEL AS IT APPROACHES THE EAST COAST OF AFRICA OVER THE NEXT 24 HOURS.

AN AREA OF CONVECTION (INVEST 91S) HAS PERSISTED NEAR 10.5S 93.2E, APPROXIMATELY 238 NM WEST-NORTHWEST OF COCOS ISLAND. ANIMATED MULTISPECTRAL SATELLITE IMAGERY(MSI) AND A 072353Z SSMIS 91GHZ MICROWAVE IMAGE DEPICT A BROAD LOW LEVEL CIRCULATION (LLC) WITH CENTRALIZED FLARING CONVECTION EXTENDING OUTWARDS TO THE NORTHWESTERN PERIPHERY. ENVIRONMENTAL ANALYSIS REVEALS A MARGINALLY UNFAVORABLE ENVIRONMENT FOR FURTHER DEVELOPMENT WITH MODERATE TO HIGH (20-25KTS) VWS, WEAK TO MODERATE UPPER-LEVEL OUTFLOW, OFFSET BY WARM (29-30C) SEA SURFACE TEMPERATURES (SST). GLOBAL DETERMINISTIC MODELS ARE IN GOOD AGREEMENT THAT 91S WILL CONTINUE ON AN EASTWARD TRACK INTO A MORE FAVORABLE ENVIRONMENT WHILE CONSOLIDATING AND STRENGTHENING OVER THE NEXT 48 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 22 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 LOW.

GLOBAL DETERMINISTIC MODELS ARE IN GOOD AGREEMENT THAT 91S WILL CONTINUE ON AN EASTWARD TRACK INTO A MORE FAVORABLE ENVIRONMENT WHILE CONSOLIDATING AND STRENGTHENING OVER THE NEXT 48 HOURS.

GTH Outlook Discussion Last Updated - 03/05/24 Valid - 03/13/24 - 03/26/24 The Madden-Julian Oscillation (MJO) strengthened at the beginning of March as a more coherent wave-1 pattern of anomalous upper-level divergence (convergence) developed over the Indian Ocean (eastern Pacific). The RMM-based MJO index gained amplitude since the end of February and is currently shifting from phases 3 to 4. Dynamical models remain consistent and in good agreement that a moderate to strong MJO propagates eastward to the Pacific Ocean during mid to late March. Given this predicted evolution, MJO precipitation and tropical cyclone composites for phases 5, 6, and 7 were used as guidance in the weeks 2 and 3 GTH outlook. Although enhanced convection recently weakened near the Date Line due to the suppressed phase of the MJO, sea surface temperatures remain above-normal across the central and eastern equatorial Pacific and El Nino is expected to continue playing a role in global tropical rainfall. No tropical cyclones (TCs) formed from February 28 to March 5 but the large-scale environment is likely to become more favorable for development initially over the Indian Ocean and then shift eastward to northern Australia. Prior to week-2, the GFS and ECMWF models are depicting multiple TCs forming over the Mozambique Channel, South Indian Ocean, and offshore of the Kimberley Coast of Australia. Dynamical model output and MJO composites support a greater than 60 percent chance of TC development near the Kimberley Coast of Australia and Gulf of Carpentaria during week-2 (March 13-19). A broader 20 to 60 percent chance extends from the South Indian Ocean to the Coral Sea. By week-3 (March 20 to 26), the GEFS has the strongest signal for TC genesis over the Gulf of Carpentaria and based on the predicted MJO progression, a greater than 40 percent chance is justified. A 20 to 40 percent chance of TC development continues near the Kimberley Coast of Australia and MJO composites support a large favored TC genesis area from the Coral Sea to the South Pacific. Since powerful tropical cyclone Jasper in December 2023, six TCs have formed in the South Pacific but all were relatively weak.