JTWC IS ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON 28W(RAI). 3HOURLY SATELLITE BULLETINS WERE DISCONTINUED AT 17/1430UTC ON 29W.
18/0130UTC.
WESTERN NORTH PACIFIC/SOUTH CHINA SEA: TY 28W(RAI). WARNING 21 ISSUED AT 18/03UTC.
FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TY RAI IS EXPECTED TO INCREASE IN SURFACE SPEED AS IT APPROACHES THE SUBTROPICAL RIGE AXIS (STR) OVER THE NEXT 24 HOURS. AS IT DOES, THE SYSTEM WILL CONTINUE TO BE IN A FAVORABLE ENVIRONMENT AND WILL MAINTAIN ITS MAX INTENSITY OF 110 KTS/CAT 3. AFTER 24H, TY RAI WILL CROSS THE 25C ISOTHERM AND WILL REMAIN OVER RELATIVELY COOLER WATERS FOR THE REMAINDER OF THE FORECAST PERIOD. BY 36H, TY 28W WILL MAKE ITS TURN NORTHWARD AS IT ROUNDS THE RIDGE AXIS AND WILL ALSO BEGIN TO APPROACH A BROAD AREA OF INCREASED VWS THAT WILL ONLY INCREASE IN SHEAR OVER THE DURATION OF THE FORECAST PERIOD. BY 48H, TY RAI WILL MAKES ITS TURN NORTHEASTWARD TO THE OPEN WATERS OF THE NORTHERN SOUTH CHINA SEA AND WILL BEGIN TO LOSE ITS MOISTURE AS DRIER AIR FROM THE WEST BEGINS TO GET WRAPPED INTO THE CENTER THROUGH THE SOUTHERN PERIPHERY. AT THIS TIME, THE SYSTEM WILL FALL UNDER THE INFLUENCE OF STRONG WESTERLIES AND BEGIN DISSIPATION. TY RAI IS FORECAST TO BE COMPLETELY DISSIPATED BY 96H, WITH THE POSSIBILITY OF DISSIPATION OCCURRING SOONER.
CLICK ON THE IMAGERY BELOW TO GET IT ANIMATED AND ENLARGED.
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS CONTINUING DEEP CONVECTION ROTATING OVER AN ASSESSED LOW LEVEL CIRCULATION CENTER. A 172318Z SSMIS 91GHZ IMAGE SHOWS A WELL-DEFINED MICROWAVE EYE WITH THE STRONGEST CONVECTION SEEN IN THE WESTERN SEMI-CIRCLE. TY RAI IS IN A FAVORABLE ENVIRONMENT FOR ONGOING DEVELOPMENT WITH STRONG WESTWARD AND POLEWARD OUTFLOW ALOFT, LOW (5-10 KT) VERTICAL WIND SHEAR (VWS), AND WARM (28-29 C) SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED MICROWAVE IMAGERY. THE INITIAL INTENSITY OF 110 KTS/CAT 3 IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON ANALYSIS OF MICROWAVE STRUCTURE AND HEDGED HIGHER THAN MUTLI-AGENCY AND AUTOMATED DVORAK ESTIMATES.
THE EYE FEATURE IS NOW WELL DEPICTED ON VISIBLE IMAGERY.
HWRF AT 17/18UTC: 108KNOTS AT +18H.
GFS ENSEMBLE AT 17/18UTC.
ECMWF ENSEMBLE AT 17/18UTC.
NORTH INDIAN OCEAN/BAY OF BENGAL: INVEST 94B. STILL LOW. ADVISORY(ABIO) ISSUED AT 17/18UTC.
AN AREA OF CONVECTION (INVEST 94B) PREVIOUSLY LOCATED NEAR 4.4N 87.4E IS NOW LOCATED NEAR 5.4N 88.4E APPROXIMATELY 950 KM EAST OF COLOMBO, SRI LANKA. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN AREA OF MID-LEVEL TURNING WITH FLARING CONVECTION IS OVER A BROAD LOW LEVEL CIRCULATION (LLC). A 171554Z ASCAT-B PASS REVEALS PRIMARILY 15 KT WINDS IN THE NORTHERN PERIPHERY OF THE AFOREMENTIONED LLC. ENVIRONMENTAL ANALYSIS INDICATES INVEST 94B IS IN AN UNFAVORABLE ENVIRONMENT WITH LITTLE UPPER LEVEL OUTFLOW AND HIGH (30-40 KT) VERTICAL WIND SHEAR, OFFSET BY FAVORABLE, WARM (29- 30 C) SEA SURFACE TEMPERATURES. GLOBAL MODELS ARE IN AGREEMENT THAT INVEST 94B WILL TRACK EASTWARD TOWARD MYANMAR OVER THE NEXT 24-48HRS WITH LITTLE TO NO DEVELOPMENT AS A TROPICAL SYSTEM. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1010 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.
GLOBAL MODELS ARE IN AGREEMENT THAT INVEST 94B WILL TRACK EASTWARD TOWARD MYANMAR OVER THE NEXT 24-48HRS WITH LITTLE TO NO DEVELOPMENT AS A TROPICAL SYSTEM.
