Invest 97W rapid intensification likely after intial consolidation//TC 19S(FABIEN) slow weakening next 72hours//1909utc

JTWC IS ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TC 19S(FABIEN). 3HOURLY SATELLITE BULLETINS ARE ISSUED ON INVEST 97W.

THE AREA OF CONVECTION (INVEST 97W) PREVIOUSLY LOCATED NEAR 5.2N 147.7E IS NOW LOCATED NEAR 4.6N 149.1E, APPROXIMATELY 588 NM SOUTH- SOUTHEAST OF GUAM, USA. ANIMATED ENHANCED MULTISPECTRAL SATELLITE IMAGERY AND A 182327Z AMSU-B 89GHZ MICROWAVE PASS DEPICT GRADUALLY CONSOLIDATING CONVECTIVE CLOUD LINES GRADUALLY WRAPPING INTO A MOSTLY OBSCURED LOW LEVEL CIRCULATION CENTER (LLCC). ENVIRONMENTAL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH LOW TO MODERATE (10-15KT) VWS, WARM SEA SURFACE TEMPERATURE (30-31C), AND MODERATE POLEWARD OUTFLOW ALOFT. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 97W WILL TRACK NORTH-NORTHWESTWARD AS IT CONSOLIDATES OVER THE NEXT 12-24 HOURS. THERE IS SIGNIFICANT UNCERTAINTY ASSOCIATED WITH WHERE THE PRIMARY LLCC WILL EVENTUALLY DEVELOP. HOWEVER, ONCE THE LLCC IS ESTABLISHED, IT IS LIKELY THAT THE SYSTEM WILL BECOME A RAPIDLY INTENSIFYING TROPICAL CYCLONE. ANY SUBSEQUENT WARNING AND ASSOCIATED TRACK FORECAST WILL BE HIGHLY CONTINGENT UPON THE LOCATION OF THE LLCC ONCE IT BECOMES ESTABLISHED. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS HIGH.

GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 97W WILL TRACK NORTH-NORTHWESTWARD AS IT CONSOLIDATES OVER THE NEXT 12-24 HOURS.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY AND MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICT AN UNRAVELLING, SLOW-MOVING SYSTEM. THE CONVECTIVE STRUCTURE IS NEARLY NON-EXISTENT AND REMAINS SOLELY ON THE SOUTHERN SECTOR OF THE LLCC AS INDICATED ON THE 230041Z SSMIS 91GHZ IMAGE. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE USING BOTH THE MICROWAVE IMAGERY FROM THE 230041Z SSMIS 91GHZ AND 37GHZ IMAGES, ALONG WITH THE MSI LOOP. THE LACK OF CONVECTION IS MAINLY DUE TO THE SLOW PROGRESSION, COMBINED WITH THE UPWELLING AND THE DRY-AIR AS DISCUSSED IN PREVIOUS FORECASTS. THE INITIAL INTENSITY OF 65KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON MULTIPLE AGENCY DVORAK INTENSITY AND OBJECTIVE AUTOMATED INTENSITY ESTIMATES. ENVIRONMENTAL CONDITIONS REMAIN MARGINALLY UNFAVORABLE WITH MODERATE (20-25KTS) VWS, WARM (28-29C) SSTS, AND MODERATE POLEWARD OUTFLOW.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 19S (FABIEN) WILL SLOWLY MIGRATE UNDER THE WEAK STEERING FROM THE STR TO THE SOUTH AND TRACK WEST-SOUTHWESTWARD. THE CONVECTION WILL AGAIN DEVELOP SLIGHTLY AS THE SUN RISES OVER THE INDIAN OCEAN AND TC 19S MOVES OVER WARMER WATER. AS THE SYSTEM TRACKS TO THE WEST, IT WILL MAINTAIN THE 65KTS INTENSITY UNTIL TAU 24. THEREAFTER, THE SYSTEM WILL WEAKEN STEADILY AND TURN POLEWARD BY TAU 36 INTO A HIGHER WIND-SHEAR ENVIRONMENT. THE SYSTEM WILL TRANSITION TO A NEW PRIMARY STEERING INFLUENCE FROM A BUILDING STR OVER MADAGASCAR BETWEEN TAUS 24 AND 36. THE SYSTEM WILL THEN MOVE INTO AN EVEN GREATER WIND SHEAR ENVIRONMENT, WHICH WILL SIGNIFICANTLY DECREASE THE INTENSITY TO 35KTS BY TAU 120, IF NOT SOONER.

MODEL DISCUSSION: EXCLUDING AFUM AND NAVGEM FROM THE MODEL GUIDANCE ENHANCES THE CROSS-TRACK SPREAD. THE MODELS ARE NEAR IDENTICAL IN THE CROSS-TRACK OUT TO TAU 36 AND ONLY HAVE A 16NM SPREAD. HOWEVER, THE ALONG-TRACK TIMING FOR STORM TO TURN POLEWARD IS IN POOR AGREEMENT. THE MEMBERS ARE STILL TRYING TO RESOLVE THE COMPLEX STEERING PATTERN DISCUSSED ABOVE, AND FOR THIS REASON, THE JTWC FORECAST TRACK IS PLACED WITH ONLY MEDIUM CONFIDENCE INITIALLY AND WITH LOW CONFIDENCE IN THE EXTENDED TRACK FORECAST. THE MODEL INTENSITY GUIDANCE IS IN FAIR AGREEMENT WITH A BULK OF THE GUIDANCE. MOST MODELS GRADUALLY DECLINE THE INTENSITY FROM TAU 00 THROUGH TAU 120. HOWEVER, THE SYSTEM MAY DEGRADE FASTER THAN THE JTWC INTENSITY FORECAST, WHICH IS PLACED CLOSE TO THE MULTI-MODEL CONSENSUS WITH MEDIUM CONFIDENCE IN THE NEAR TAUS AND LOW IN THE LATTER HALF.