TC 19S(GOMBE): crossing Northern Madagascar, intensity at landfall likely under-estimated//Invest 96P: subtropical, 08/03utc

JTWC IS ISSUING 12HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TC 19S(GOMBE).

08/0215UTC.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY. FORECAST DISCUSSION: TC GOMBE WILL MAKE LANDFALL OVER THE NEXT FEW HOURS, TRACK WEST-NORTHWESTWARD UNDER THE STEERING SUBTROPICAL RIDGE (STR), EXIT INTO THE MOZAMBIQUE CHANNEL BY 36H, DRIFT WEST-SOUTHWESTWARD, THEN SOUTHWARD BY 96H AS IT ROUNDS THE WESTERN EDGE OF THE STR AXIS. INTERACTION WITH THE RUGGED TERRAIN ACROSS NORTHERN MADAGASCAR WILL WEAKEN THE CYCLONE DOWN TO 30KTS UP TO 36H. AFTERWARD, THE WARM SST IN THE MOZAMBIQUE CHANNEL PLUS CONTINUED FAVORABLE VWS AND OUTFLOW WILL FUEL STEADY INTENSIFICATION TO A PEAK OF 65KTS/CAT 1 US BY 96H. AFTERWARD, INCREASING VWS WILL OFFSET THE OTHER DYNAMICS AND WEAKEN THE CYCLONE DOWN TO 45KTS BY 120H.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A MEDIUM-SIZED, FAIRLY SYMMETRICAL SYSTEM WITH MINIMAL RAIN BANDS THAT HAS SIGNIFICANTLY DEEPENED AS IT IS ABOUT TO MAKE LANDFALL OVER NORTHEASTERN MADAGASCAR. THE INITIAL INTENSITY IS BASED WITH MEDIUM CONFIDENCE ON A PARTLY EXPOSED LOW LEVEL CIRCULATION FEATURE IN THE 071810Z AMSU-B MICROWAVE IMAGE. THE INITIAL INTENSITY OF 35KTS IS HELD SLIGHTLY HIGHER THAN THE 30-KT MAX INTENSITY INDICATED IN THE 071456Z SMAP PASS AND MORE IN LINE WITH THE FMEE DVORAK ESTIMATE OF T2.5. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH LOW TO MODERATE (15-2OKT) VWS, MODERATE RADIAL OUTFLOW, AND WARM SST OFFSET BY LAND INTERACTION WITH MADAGASCAR. THE CYCLONE IS TRACKING SLOWLY ALONG THE NORTHERN PERIPHERY OF THE STR TO THE SOUTH.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT BUT GIVEN THE UNCERTAINTIES IN THE INITIAL TRACK OVER LAND, THERE IS OVERALL MEDIUM CONFIDENCE IN THE JTWC TRACK FORECAST.