TC 13S(DINGANI) to peak at 70knots/CAT 1 US by 36h//TC 11S(FREDDY) to reach CAT 3 US by 36h//12P(GABRIELLE) subtropical//1109utc

JTWC IS ISSUING 12HOURLY WARNINGS ON TC 11S(FREDDY) AND TC 13S(DINGANI).3HOURLY SATELLITE BULLETINS ARE ISSUED ON TC 11S, TC 13S AND STS 12P(GABRIELLE).

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS CONVECTIVE BANDING WRAPPING TIGHTLY INTO A DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC). ANIMATED ENHANCED INFRARED SATELLITE IMAGERY INDICATES A MORE ILL-DEFINED LLCC WITH DEEP CONVECTION DISPLACED PRIMARILY OVER THE WESTERN SEMICIRCLE DUE TO THE NORTHEASTERLY VERTICAL WIND SHEAR. AN 110423Z GMI 89GHZ MICROWAVE IMAGE REVEALS A WEAK MICROWAVE EYE FEATURE WITH FRAGMENTED CONVECTIVE BANDING. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE MSI AND GMI IMAGE. THE INITIAL INTENSITY OF 50 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON AN AVERAGE OF THE DVORAK CURRENT INTENSITY ESTIMATES, WHICH IS CONSISTENT WITH THE MICROWAVE EYE STRUCTURE.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 13S IS FORECAST TO TURN WEST-SOUTHWESTWARD TO SOUTHWESTWARD AS IT TRACKS ALONG THE NORTHWESTERN PERIPHERY OF THE STR OVER THE NEXT 48 HOURS. TC 13S IS EXPECTED TO INTENSIFY TO A PEAK INTENSITY OF 70 KNOTS DUE TO ENHANCED POLEWARD OUTFLOW INTO AN APPROACHING UPPER-LEVEL SHORT-WAVE TROUGH. ADDITIONALLY, VERTICAL WIND SHEAR (VWS) WILL REMAIN LOW WITH FAVORABLE SST VALUES OF 27-28C. AFTER TAU 48, ENVIRONMENTAL CONDITIONS WILL DEGRADE QUICKLY AS THE SYSTEM FIRST INTERACTS WITH THE SHORTWAVE TROUGH THEN TRACKS UNDER STRONG NORTHWESTERLY FLOW WITH HIGH (30 TO 40 KNOTS) VWS. CONSEQUENTLY, TC 13S WILL WEAKEN STEADILY THROUGH THE REMAINDER OF THE FORECAST PERIOD. THE SYSTEM SHOULD SLOW NEAR TAU 120 AS IT ENCOUNTERS A STRONG LOW- LEVEL HIGH EXPECTED TO BUILD TO THE SOUTH.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN TIGHT AGREEMENT THROUGH TAU 48 WITH A 65NM SPREAD IN SOLUTIONS AT TAU 48. AFTER TAU 48, THERE IS INCREASING UNCERTAINTY WITH A 415NM SPREAD IN SOLUTIONS AT TAU 120. THE BULK OF THE DETERMINISTIC AND PROBABILISTIC GUIDANCE SUPPORTS THE JTWC FORECAST TRACK WITH A MORE SOUTHWESTWARD TRACK. HOWEVER, ABOUT 15 PERCENT OF THE 110000Z ECMWF ENSEMBLE SOLUTIONS, AS WELL AS THE NVGI AND AEMI TRACKERS, INDICATE A MORE WESTWARD TO WEST-SOUTHWESTWARD TRACK TOWARD LA REUNION AND MAURITIUS. THIS SCENARIO IS CURRENTLY ASSESSED AS UNLIKELY AS THESE SOLUTIONS TRACK THE SYSTEM DIRECTLY INTO THE AFOREMENTIONED UPPER-LEVEL TROUGH. DUE TO THIS, THESE SOLUTIONS GENERALLY WEAKEN THE SYSTEM TO TROPICAL DEPRESSION STRENGTH.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A COMPACT SYSTEM THAT HAS MAINTAINED OVERALL SYMMETRICAL CONVECTIVE SIGNATURE WITH SHORT SHALLOW FEEDER BANDS WRAPPED CLOSE TO THE CORE. THE CENTRAL DENSE OVERCAST HAS SLIGHTLY DEEPENED OVER THE LAST 12 HRS. THE INITIAL POSITION IS EXTRAPOLATED WITH HIGH CONFIDENCE FROM A MICROWAVE EYE FEATURE IN THE 102206Z SSMIS 89GHZ IMAGES. THE INITIAL INTENSITY IS ALSO PLACED WITH HIGH CONFIDENCE BASED ON AN OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE SLIGHT 12-HR IMPROVEMENT. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH WARM SST, LOW VWS, AND WITH MODERATE RADIAL OUTFLOW.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC FREDDY WILL CONTINUE ON A GENERALLY WESTWARD TO WEST-SOUTHWESTWARD TRACK UNDER THE STEERING STR. THE FAVORABLE ENVIRONMENT WILL FUEL A STEADY INTENSIFICATION TO 100KTS BY 36. AFTERWARD, INCREASING VWS WILL OFFSET THE FAVORABLE SST AND OUTFLOW AND TEMPORARILY WEAKEN THE SYSTEM DOWN TO 75KTS BY TAU 72. AFTER TAU 72, VWS WILL ONCE AGAIN RELAX PROMOTING ANOTHER INTENSIFICATION PHASE AND BY TAU 120, THE INTENSITY WILL REACH 100KTS.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY GOOD AGREEMENT WITH AN EVEN AND GRADUAL SPREAD TO 234NM BY TAU 120, LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. THE INTENSITY FORECAST IS AT MEDIUM CONFIDENCE FOR THE DURATION OF THE FORECAST DUE TO THE UP-AND-DOWN INTENSITY CHANGES.