Green Alert Country(s) or Province(s)
Madagascar
probability for TS is 50% currently
Note that
Green Alert (Low) is TS to between 31% and 50% probability.
TS means Tropical Storm strength winds of at least 39 mph, 63 km/h or 34 knots 1-min sustained.
For graphical forecast information and further details please visit http://www.tropicalstormrisk.com/
170300Z POSITION NEAR 22.8S 42.3E. TROPICAL CYCLONE (TC) 09S (DELIWE), LOCATED APPROXIMATELY 325 NM SOUTHWEST OF ANTANANARIVO, MADAGASCAR, HAS TRACKED SOUTHWESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THE SYSTEM HAS FURTHER CONSOLIDATED, ALBEIT MARGINALLY, AS THE CENTRAL DENSE OVERCAST FEATURE DEEPENED. THE SAME ANIMATION ALSO SHOWS A PERSISTENTLY STRONG POLEWARD OUTFLOW CHANNEL; HOWEVER, THE NORTHWESTWARD CHANNEL HAS ALL BUT EXTINGUISHED. THE INITIAL INTENSITY AND POSITION ARE BASED ON CLOSELY-GROUPED AND CONGRUENT DVORAK FIX ESTIMATES FROM PGTW, KNES, AND FMEE. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS IN THE VICINITY OF A RIDGE AXIS IN AN AREA OF MODERATE (20-25 KNOT) VERTICAL WIND SHEAR (VWS). HOWEVER, THE SAME RIDGE IS PRIMARILY RESPONSIBLE FOR THE STRONG POLEWARD OUTFLOW THAT IS ENHANCING THE DEEP CONVECTION. THE CYCLONE IS TRACKING ALONG THE WESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) CENTERED JUST EAST OF MADAGASCAR. OVER THE NEXT 24 HOURS, IT IS EXPECTED TO CONTINUE DRIFTING GENERALLY SOUTHWESTWARD TOWARDS A COL AREA WHERE IT WILL SIGNIFICANTLY SLOW DOWN AS A NEW STR - ANCHORED OVER SOUTH AFRICA - WILL COMPETE FOR STEERING. AFTER TAU 48, THE NEW STR WILL ASSUME STEERING AND SLOWLY NUDGE THE CYCLONE NORTHWESTWARD. EVEN AS THE POLEWARD OUTFLOW CHANNEL IS EXPECTED TO REMAIN SOLID THROUGHOUT THE FORECAST PERIOD, INCREASING VWS - CONCURRENT WITH THE POLEWARD MOTION OF THE CYCLONE - WILL STIFLE ANY SIGNIFICANT INTENSIFICATION. TC DELIWE IS FORECAST TO FLAT-LINE AT 45 KNOTS BEFORE GRADUALLY WEAKENING AFTER TAU 48 DUE TO DIMINISHING OUTFLOW WITH THE ONSET OF THE NEW STEERING STR. THE AVAILABLE NUMERIC GUIDANCE IS IN FAIR AGREEMENT; HOWEVER, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST DUE TO THE STEERING UNCERTAINTY IN THE COL AREA. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 170000Z IS 10 FEET.
- tropicalstormalert.com + JTWC
