TC 19S(GOMBE): rapid intensification next 24h up to dangerous CAT 3 at landfall over Mozambique, major flooding possible,10/03utc

JTWC IS ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TC 19S(GOMBE).

10/02UTC.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 19S IS TRACKING WESTWARD UNDER THE STEERING INFLUENCE OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE SOUTH, AND IS EXPECTED TO TRACK GENERALLY WESTWARD OVER THE NEXT 48 HOURS. VERY FAVORABLE ENVIRONMENTAL CONDITIONS SUPPORT RAPID INTENSIFICATION THROUGH LANDFALL NEAR 24H OVER THE EASTERN COAST OF MOZAMBIQUE WITH A PEAK INTENSITY OF 100 KNOTS/CAT 3 AT 24H. AFTER 48H, THE STEERING RIDGE IS EXPECTED TO WEAKEN WITH THE APPROACH OF A DEEP MIDLATITUDE TROUGH AND, CONSEQUENTLY, TC 19S SHOULD SLOW OVER MOZAMBIQUE WHICH WILL LIKELY LEAD TO SIGNIFICANT RAINFALL AND MAJOR FLOODING AS THE SYSTEM STALLS. TC 19S WILL DISSIPATE QUICKLY OVERLAND, HOWEVER, AFTER 72H, THE STR WILL RE-ORIENT NORTH-SOUTH AND WILL PRODUCE A SOUTHWARD TO SOUTH-SOUTHEASTWARD TRACK WITH THE SYSTEM REMNANTS EXPECTED TO RE-EMERGE OVER THE MOZAMBIQUE CHANNEL. THERE IS MODERATE PROBABILITY THAT THE SYSTEM MAY RE-DEVELOP INTO A WEAK TROPICAL CYCLONE UNDER GENERALLY FAVORABLE CONDITIONS.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A COMPACT SYSTEM WITH AN IRREGULAR CENTRAL DENSE OVERCAST OBSCURING THE LOW-LEVEL CIRCULATION CENTER (LLCC) AND SPIRAL BANDING OVER THE WESTERN PERIPHERY. A 092253Z AMSR2 89GHZ MICROWAVE IMAGE, HOWEVER, SHOWS A DEVELOPING EYEWALL WITH A SMALL MICROWAVE EYE FEATURE WHICH SUPPORTS THE INITIAL POSITION WITH HIGH CONFIDENCE, AND ALSO PROVIDES ADDITIONAL EVIDENCE THAT THE SYSTEM HAS CONTINUED TO CONSOLIDATE. THE 34-KNOT AND 50-KNOT WIND RADII WERE ADJUSTED SLIGHTLY BASED ON THE AMSR2 25KM RESOLUTION WINDSPEED PRODUCT THAT SHOWS NUMEROUS 50-55 KNOT WINDS OVER THE NORTHERN SEMI-CIRCLE. THE INITIAL INTENSITY OF 60 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON AN AVERAGE OF DVORAK ESTIMATES RANGING FROM 55 TO 65 KNOTS. RECENT ADT AND SATCON ESTIMATES REMAIN SLIGHTLY LOWER AT 53-54 KNOTS. ENVIRONMENTAL CONDITIONS REMAIN VERY FAVORABLE WITH LOW VERTICAL WIND SHEAR, WARM SST (29-30C) AND NEAR-RADIAL OUTFLOW.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE SUPPORTS THE JTWC FORECAST TRACK WITH HIGH CONFIDENCE THROUGH 48H WITH A 65KM TO 85KM SPREAD IN SOLUTIONS FROM 36H TO 48H. AFTER 72H, MODEL GUIDANCE DIVERGES WITH LOW OVERALL TRACK CONFIDENCE DUE TO THE RAPIDLY WEAKENING STR AND INITIAL INTERACTION WITH THE MIDLATITUDE TROUGH. RELIABLE INTENSITY GUIDANCE SUPPORTS THE JTWC FORECAST PHILOSOPHY WITH HWRF AND COAMPS-TC (GFS VERSION) INDICATING A PEAK OF 90-95 KNOTS BY 24H. ADDITIONALLY, RAPID INTENSIFICATION AIDS HAVE TRIGGERED SUPPORTING THE INCREASING PROBABILITY OF RAPID INTENSIFICATION (RI) OCCURRING WITHIN THE NEXT 24 HOURS. THE JTWC INTENSITY FORECAST IS POSITIONED ABOVE THE JTWC INTENSITY CONSENSUS (ICNW), WHICH PEAKS AT 83 KNOTS. THE LATEST COAMPS-TC ENSEMBLE GUIDANCE (091800Z) INDICATES A 70 TO 75 PERCENT PROBABILITY OF RI OCCURRING WITHIN THE NEXT 24 HOURS, WHICH FURTHER BOLSTERS THE JTWC INTENSITY FORECAST PHILOSOPHY. JTWC INTENSITY GUIDANCE IS MIXED ON REGENERATION WITH SOME GUIDANCE INDICATING A 35- 40 KNOT INTENSITY AT DAY 5. THE COAMPS-TC ENSEMBLE ALSO SHOWS A 20 TO 40 PERCENT PROBABILITY OF MODERATE INTENSIFICATION.