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JTWC IS ISSUING 6HOURLY WARNINGS ON TC 18S. 3HOURLY SATELLITE BULLETINS ARE ISSUED ON TC 18S AND INVEST 90W.
SOUTH INDIAN OCEAN/WESTERN AUSTRALIA: TC 18S(ILSA). CURRENT ESTIMATED INTENSITY IS 115 KNOTS CAT 4 US AT 13/00UTC.
1823041118 155S1204E 80
1823041200 157S1199E 80
1823041206 160S1197E 90
1823041212 165S1195E 100
1823041218 171S1193E 105
1823041300 177S1191E 115
1823041200 157S1199E 80
1823041206 160S1197E 90
1823041212 165S1195E 100
1823041218 171S1193E 105
1823041300 177S1191E 115
WARNING 18 ISSUED AT 13/03UTC.
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SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A LARGE, HIGHLY SYMMETRICAL SYSTEM WITH A DIMPLED EYE. CENTRAL CONVECTION RAPIDLY DEEPENED AND RAIN BANDS WRAPPED TIGHTER INTO THE CENTER OVER THE LAST SIX HOURS. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE DIMPLED EYE, ADJUSTED FOR A SLIGHT WESTWARD TILT. THE INITIAL INTENSITY OF 115KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE HIGH END OF AUTOMATED INTENSITY ESTIMATES OPEN-AIIR AND DMN THAT ARE MORE IN LINE WITH THE IMPROVED 6-HR CONVECTIVE SIGNATURE. THE ENVIRONMENT REMAINS HIGHLY FAVORABLE WITH STRONG RADIAL OUTFLOW AND VERY WARM SST OFFSETTING THE MEDIUM VWS.
DVORAK ANALYSIS AT 13/0250UTC.
FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: A SHORTWAVE TROUGH APPROACHING FROM THE SOUTHWEST HAS BEGUN TO WEAKEN THE STEERING STR. THIS WILL ALLOW THE CYCLONE TO TRACK SOUTHWARD THEN SOUTHEASTWARD, MAKING LANDFALL APPROXIMATELY 90NM ENE OF PORT HEADLAND SHORTLY BEFORE TAU 18, THEN TRACK RAPIDLY INTO THE CENTRAL AUSTRALIAN OUTBACK. THE HIGHLY FAVORABLE CONDITIONS, COUPLED WITH INCREASED EASTWARD OUTFLOW ASSOCIATED WITH THE STRONG WESTERLIES AHEAD OF THE TROUGH, WILL SUSTAIN ITS RAPID INTENSIFICATION (RI) TO A PEAK OF 130KTS BY TAU 12 PRIOR TO LANDFALL. AFTERWARD, INCREASING VWS AND LAND INTERACTION WILL RAPIDLY ERODE THE SYSTEM TO DISSIPATION BY TAU 48.
FORECAST LANDFALL AREA
MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT WITH AN EVEN SPREAD TO 230NM BY TAU 48, LENDING HIGH CONFIDENCE IN THE JTWC TRACK FORECAST. THERE IS ONLY MEDIUM CONFIDENCE IN THE INTENSITY FORECAST DUE TO THE VARIABLES ASSOCIATED WITH RI AND LAND PASSAGE.
RIPA Forecast
HWRF 10m Wind Speed & Sea Level Pressure AT 12/18UTC: 141KNOTS AT +18H.
Multiplatform Satellite Surface Wind Analysis (Experimental)
RCM2 AT 12/2132UTC: 108 KNOTS( 1 MINUTE AVERAGE).
WESTERN NORTH PACIFIC/PHILIPPINE SEA: INVEST 90W. ESTIMATED LOCATION AND INTENSITY AT 13/00UTC. ADVISORY(ABPW) ISSUED AT 13/06UTC.
THE AREA OF CONVECTION (INVEST 90W) PREVIOUSLY LOCATED NEAR 13.5N 124.3E IS NOW LOCATED NEAR 14.8N 121.9E, APPROXIMATELY 56 NM EAST OF MANILA, PHILIPPINES. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A FULLY EXPOSED LLCC WITH FLARING CONVECTION TO THE SOUTHWEST. THERE IS NO DEEP CONVECTIVE STRUCTURE, BUT 90W HAS LOW LEVEL CLOUD LINES WRAPPING INTO A WELL DEFINED LLCC. A 130154Z ASCAT-B IMAGE SHOWS A DEFINED CIRCULATION CENTER WITH 15KT WINDS OVER POLILLO ISLAND, PHILIPPINES. 90W IS IN A PREDOMINANTLY UNFAVORABLE ENVIRONMENT DUE TO LAND INTERACTION, DESPITE LOW (10-15KTS) VERTICAL WIND SHEAR, WEAK DIVERGENCE ALOFT, EQUATORWARD OUTFLOW, AND WARM (28-29C) SST. GLOBAL MODELS INDICATE THAT 90W WILL DISSIPATE OVER LUZON IN THE NEXT 36 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.
GLOBAL MODELS INDICATE THAT 90W WILL DISSIPATE OVER LUZON IN THE NEXT 36 HOURS.
