TC 07P intensifying//TC 06S(ANGGREK) re-intensifying//TCFA issued for Invest 92S//3 Week Tropical Cyclone Formation Probability//2403utc

JTWC IS ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS TC 07P. 12HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ARE ISSUED ON TC 06S. 3HOURLY SATELLITE BULLETINS ARE ISSUED ON INVEST 92S.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS LIMITED, FRAGMENTED DEEP CONVECTION CONFINED PRIMARILY TO THE NORTHERN AND WESTERN PERIPHERIES OF A BROAD CIRCULATION WITH MULTIPLE EMBEDDED LOW-LEVEL MESOVORTICES. THE INITIAL POSITION IS PLACED WITH LOW CONFIDENCE BASED ON RECENT SATELLITE FIXES FROM PGTW AND KNES AND A PARTIAL 232029Z SSMIS MICROWAVE SENSOR PASS. THE INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH MEDIUM CONFIDENCE AND SET SLIGHTLY ABOVE A CONSENSUS OF SUBJECTIVE DVORAK AND AUTOMATED INTENSITY ESTIMATES BASED ON WINDS EXCEEDING 35 KNOTS EVIDENT WITHIN THE SOUTHEASTERN PERIPHERY IN A PARTIAL 232222Z METOP-B ASCAT PASS. ALTHOUGH CONVECTION REMAINS DISORGANIZED AND COVERAGE HAS DECREASED, AN EXPANDING CIRRUS SHIELD OVER THE SYSTEM REFLECTS AN EXPANSION OF OUTFLOW, PARTICULARLY TO THE WEST, AS WELL AS THE DISSIPATION OF A WEAK UPPER-LEVEL LOW THAT WAS PREVIOUSLY INHIBITING DEVELOPMENT.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 07P WILL ACCELERATE WEST-SOUTHWESTWARD OVER THE NEXT 36 HOURS AS THE STR CONTINUES TO BUILD TO THE SOUTH AND REMAINS THE DOMINANT STEERING MECHANISM. SLOW BUT STEADY INTENSIFICATION IS LIKELY OVER THE NEXT 36 HOURS AS IMPROVING OUTFLOW AND PASSAGE OVER WARM WATER SUPPORT SOME DEVELOPMENT OF THE BROAD AND DISORGANIZED CIRCULATION. RAPID INTENSIFICATION IS VERY UNLIKELY AS THE BROAD CIRCULATION HAS ONLY LIMITED TIME TO CONSOLIDATE. THE SYSTEM WILL RAPIDLY WEAKEN AS IT TRACKS INLAND AFTER TAU 36 AND WILL DISSIPATE BY TAU 72.

MODEL DISCUSSION: NUMERICAL MODEL TRACK FORECAST GUIDANCE IS IN VERY GOOD AGREEMENT WITH RESPECT TO THE FORECAST TRACK. HOWEVER, GIVEN THE BROAD NATURE OF THE CIRCULATION, THE STRONGEST CONVECTION AND WINDS WILL LIKELY CONTINUE TO BE DISPLACED FROM THE CIRCULATION CENTER PRIOR TO LANDFALL. CONSENSUS DYNAMICAL AND STATISTICAL- DYNAMICAL MODELS ALL DEPICT A SLOW UPWARD TREND TOWARD A PEAK INTENSITY IN THE 45 TO 55 KNOT RANGE PRIOR TO LANDFALL. GIVEN THE STRAIGHTFORWARD STEERING PATTERN DEVELOPMENT FACTORS, CONFIDENCE IN BOTH THE TRACK AND INTENSITY FORECASTS IS HIGH.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: FORECAST INTENSITIES IN THE EXTENDED PERIOD HAVE INCREASED BY ABOUT 20 KNOTS RELATIVE TO THE PREVIOUS FORECAST CONSISTENT WITH CHANGES IN THE NUMERICAL FORECAST GUIDANCE PACKAGE. HOWEVER, THE OVERALL FORECAST PHILOSOPHY HAS NOT CHANGED SIGNIFICANTLY. FORECAST DISCUSSION: TC 06S WILL TRACK SOUTHWESTWARD TO WEST-SOUTHWESTWARD THROUGH THE DURATION OF THE FORECAST ALONG THE NORTHERN PERIPHERY OF BUILDING SUBTROPICAL RIDGING TO THE SOUTH AND EAST. TRANSLATIONAL SPEED WILL INCREASE STEADILY AS THE STEERING RIDGE BUILDS. WITH POLEWARD OUTFLOW INCREASING AND THE SYSTEM MOVING OVER WARMER WATER, STEADY NEAR-TERM INTENSIFICATION IS LIKELY. IN THE EXTENDED RANGE, A MORE RESTRICTED OUTFLOW PATTERN AND SLIGHT INCREASE IN VERTICAL WIND SHEAR IS EXPECTED TO HALT THE INTENSIFICATION TREND.

BOTH DETERMINISTIC AND ENSEMBLE MODEL FORECASTS ARE IN VERY GOOD AGREEMENT REGARDING THE TRACK, PARTICULARLY FOR THE FIRST 72 HOURS OF THE FORECAST PERIOD, REFLECTING THE RELATIVELY STRAIGHTFORWARD STEERING PATTERN. IN CONTRAST, INTENSITY FORECAST GUIDANCE DIVERGES SIGNIFICANTLY, WITH HAFS AND COAMPS-TC INDICATING THE POTENTIAL FOR PRONOUNCED INTENSIFICATION AT DIFFERENT POINTS IN THE FORECAST PERIOD AND THE REMAINDER OF THE GUIDANCE PREDICTING A SMOOTHER INTENSIFICATION TREND AS REFLECTED IN THE CURRENT JTWC OFFICIAL FORECAST. RAPID DEVIATIONS IN INTENSITY ARE NOT UNUSUAL FOR A SMALL SYSTEM LIKE TC 06S, SO ADDITIONAL UPDATES TO THE INTENSITY FORECAST MAY BE WARRANTED IN SUBSEQUENT FORECASTS.

THE AREA OF CONVECTION (INVEST 92S) PREVIOUSLY LOCATED NEAR 19.6S 58.8E IS NOW LOCATED NEAR 20.1S 57.9E, APPROXIMATELY 23 NM EAST-NORTHEAST OF MAURITIUS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) AND A PARTIAL 2317157Z METOP-B ASCAT DEPICT A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH THE STRONGEST WIND ASSOCIATED WITH PERSISTENT FLARING CONVECTION PLACED TO THE WEST- NORTHWEST. A RECENT MAURITIUS OBSERVATION SHOWS A DYNAMIC DROP IN PRESSURE BY 7 MB IN THE LAST 24 HOURS. WHILE A SHIP OBSERVATION TO SOUTHWEST IS SHOWS SOUTHERLY WINDS AT 28 KNOTS. ENVIRONMENTAL ANALYSIS INDICATES THAT 92S IS IN A MARGINALLY FAVORABLE ENVIRONMENT FOR FURTHER DEVELOPMENT WITH WEAK EQUATORWARD OUTFLOW ALOFT, LOW TO MODERATE (15-20 KTS) VERTICAL WIND SHEAR, AND WARM (28-29 C) SEA SURFACE TEMPERATURES. MODEL GUIDANCE INDICATES THAT THE SYSTEM IS CURRENTLY PASSING MAURITIUS AND WILL CONTINUE TO BECOME MORE ORGANIZED OVER THE NEXT 24 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 998 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO HIGH.

MODEL GUIDANCE INDICATES THAT THE SYSTEM IS CURRENTLY PASSING MAURITIUS AND WILL CONTINUE TO BECOME MORE ORGANIZED OVER THE NEXT 24 HOURS.

Last Updated - 01/23/24 Valid - 01/31/24 - 02/13/24 Following a period of competing interference with other modes of tropical variability, the MJO became more coherent as it propagated eastward over the Maritime Continent and into the Western Pacific. Good agreement exists in the dynamical models looking ahead, which initially favor a high amplitude MJO signal over the Western Pacific that weakens and slows after the week-1 period. Enhanced convection associated with MJO activity is expected to provide favorable conditions for Tropical Cyclone (TC) development over the South Pacific Ocean, while a lingering potential for TC activity for the western Indian Ocean remains despite an unfavorable position of the MJO. The extratropical response with wintertime Maritime Continent and West Pacific MJO events typically leads to the development of warmer than normal temperatures over the central and eastern U.S. Strong subtropical westerly flow is forecast both near the surface and aloft, potentially leading to atmospheric river activity to affect the West Coast of the U.S. during the week-2 period. There has been one TC that formed in the last week. On January 23 TC 07P formed in the Coral Sea several hundred kilometers southeast of New Guinea. Current forecasts favor a southwest track towards the northeastern coast of Australia, while increasing modestly in intensity. For the latest information on TC 07P please refer to the Joint Typhoon Warning Center (JTWC). Model consensus for the week-2 period places the MJO in either phase 6 or 7, with enhanced convection moving from the Maritime Continent into the Western Pacific, resulting in elevated probabilities for TC formation for the South Pacific. The ECMWF extended range TC genesis forecast reflects this with probabilities of formation well over 40% for both weeks 2-3. During week-2 the highest probabilities (>40% chance) for TC genesis are centered over the Coral Sea with lower probabilities extending westward to the Gulf of Carpentaria. The GEFS extended range forecasts also indicate the enhanced potential for TC development in the Coral Sea. The South Indian Ocean has seen increased TC activity recently, and the Joint Typhoon Warning Center is currently monitoring an area of disturbed weather east of Madagascar, which is favored to become a TC in the near future. Extended range solutions from the ECMWF favor a continuation of enhanced probabilities for TC formation during week-2 for the southwestern Indian Ocean. Ensemble model solutions suggest a slowing in MJO propagation during week-3 with the RMM-index remaining in phase 6 or 7. Velocity potential anomaly forecasts indicate that the MJO should shift eastward at least modestly though, thus the moderate risk for TC genesis from week-2 continues but is shifted slightly eastward in week-3. In the South Indian Ocean, the ECMWF continues to indicate an enhanced potential for increased TC activity during the week-3 time period despite an unfavorable position of the MJO.