Western Pacific: 09W(IN-FA) is bearing down on Ishigakijima as a potential CAT 3 Typhoon, 10W(CEMPKAKA) could be back over water by 24h, 22/03utc updates

JTWC HAS BEEN ISSUING 6HOURLY WARNINGS ON 09W AND 10W. 3HOURLY SATELLITE BULLETINS ARE ISSUED FOR BOTH SYSTEMS.

09W(IN-FA). WARNING 24 ISSUED AT 22/03UTC.THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: A STRONG UPPER LEVEL HEIGHT CENTER PEAKING OVER THE SEA OF JAPAN HAS FORCED THE SYSTEM A LITTLE EQUATORWARD OF THE EXPECTED TRACK OVER THE PAST SIX HOURS BUT THE PRESSURE IS BEGINNING TO LIFT AND TY 09W WILL BEND POLEWARD IN THE NEAR FUTURE. ONCE ON ITS NORTHWESTWARD LEG, IT WILL ROAR OVER ISHIGAKIJIMA AT ITS PEAK INTENSITY OF 100KTS/CAT 3. BEYOND THE SENKAKUS SEA SURFACE TEMPERATURES WILL COOL SLIGHTLY AND WIND SHEAR WILL INCREASE, SENDING THE SYSTEM ON A PERMANENT DOWNWARD INTENSITY TREND UNTIL ITS LANDFALL SOUTH OF SHANGHAI.

09W(IN-FA). SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND A 212247Z SSMIS SERIES INDICATE THAT TY 09W IS IN THE MIDDLE OF AN EYEWALL REPLACEMENT CYCLE (ERC) AND THAT DEEP CONVECTION IS LACKING OVER THE NORTHEASTERN QUADRANT. THE ERC AND UPWELLING CAUSED BY THE RELATIVELY SLOW MOVEMENT OF THE SYSTEM HAS KEPT THE INTENSITY TREND FLAT OVER THE PAST 12 HOURS EVEN THOUGH THE UPPER LEVEL ENVIRONMENT IS IMPROVING. THE INTENSITY ASSESSMENT IS BASED ON AVERAGE OF 3 AGENCY DVORAK ESTIMATES AND THE POSITION IS BASED ON AN EYE FIX ON 28KM RAGGED EYE. A 212331UTC ASCAT PASS CONFIRMS GALE FORCE EASTERLIES EXTEND TO NORTH OF OKINAWA AND GALE FORCE NORTHERLIES OVER THE SENKAKUS. ANIMATED WATER VAPOR IMAGERY INDICATES SOME PRESSURE ON THE PERIPHERY OF THE NORTHWEST QUADRANT BUT FOR THE MOST PART THE SYSTEM IS COCOONED AND ABLE TO GENERATE MODERATE OUTFLOW IN ALL QUADRANTS.

09W(IN-FA).MODEL DISCUSSION: A MINORITY OF MEMBERS OF THE ECMWF ENSEMBLE KEEP THE SYSTEM SEAWARD OF SHANGHAI WHILE DECAYING IT, BUT THERE IS INCREASING CONFIDENCE IN THE LANDFALL SCENARIO. VORTEX TRACKERS ARE IN REASONABLY TIGHT AGREEMENT THROUGH 48H BUT BEYOND THE 27TH LATITUDE THE MEMBERS OF CONSENSUS DIVERGE SUBSTANTIALLY, WITH GFS, THE AMERICAN ENSEMBLE, AND COAMPS TC STAYING SEAWARD OF SHANGHAI. ECMWF, JGSM, AND THE JAPANESE ENSEMBLE STAY WELL WEST OF SHANGHAI. THE JTWC TRACK FORECAST STAYS WITH THE LATTER GROUPING AND CLOSE TO THE MULTI-MODEL CONSENSUS. THE INTENSITY FORECAST STAYS ON THE HIGH SIDE OF THE GUIDANCE ENVELOPE AND THEN DROPS SHARPLY BELOW CONSENSUS AS THE STORM MAKES LANDFALL, AS THE INTENSITY GUIDANCE FROM THOSE MODELS REMAINING OVER WATER IS PULLING THE INTENSITY CONSENSUS FALSELY HIGHER.

09W(IN-FA).TY 09W IS IN THE MIDDLE OF AN EYEWALL REPLACEMENT CYCLE (ERC). ONCE ON ITS NORTHWESTWARD LEG, IT WILL ROAR OVER ISHIGAKIJIMA AT ITS PEAK INTENSITY OF 100KTS/CAT 3.

10W(CEMPAKA). WARNING 15 ISSUED AT 22/03UTC.THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TD 10W MAY RE-ENTER THE GULF OF TONKIN NEAR 24H. THE FORECASTING ISSUE WITH TD 10W REMAINS HOW MUCH OF THE CORE WILL BE LEFT WHEN AND IF IT MAKES IT TO THE COAST. ONCE OUT TO SEA IN THE GULF OF TONKIN, THE SYSTEM WILL RE-GENERATE IN THE VERY WARM 30-31C WATERS AND FAVORABLE UPPER LEVEL ENVIRONMENT, BUT WILL AGAIN RUN INTO THE RUGGED TERRAIN OF HAINAN ISLAND. IF IT MAKES IT ACROSS HAINAN ISLAND, IT WILL ENCOUNTER VISCIOUS WIND SHEAR DUE TO THE NEAR GALE FORCE GRADIENT FLOW OVER THE SOUTH CHINA SEA UNDERNEATH NORTHEASTERLY UPPER LEVEL WINDS ASSOCIATED WITH OUTFLOW FROM TY 09W. THE SURVIVAL OF THE SYSTEM TURNS ON A NUMBER OF NUANCES SUCH AS EXACTLY WHERE IT ENTERS THE GULF OF TONKIN AND HOW MUCH TIME IT SPENDS OVER THE GULF OF TONKIN, AND HOW MUCH, IF ANY, OF THE VORTEX IS LEFT WHEN IT ENTERS THE SOUTH CHINA SEA. THERE IS INCREASING CONVICTION THAT THE SYSTEM WILL NOT SURVIVE VERY FAR BEYOND HAINAN ISLAND IF IT EVEN MAKES IT THAT FAR.

10W(CEMPAKA).SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DECREASING CONVECTION AND ORGANIZATION OVER TD 10W. THE MAJORITY OF DEEP CONVECTION IS FORMING ALONG THE IMMEDIATE COASTLINE DUE TO ON-SHORE FLOW. SURFACE REPORTS AND RADAR ANIMATION INDICATE THE VORTEX REMAINS INTACT AND HAS TURNED BACK TOWARDS THE COAST.

10W(CEMPAKA).MODEL DISCUSSION: GUIDANCE IS CONSISTENT IN INDICATING AN OFF-SHORE MOVEMENT NORTHEAST OF HANOI, VIETNAM AND A CYCLONIC LOOP TOWARDS THE WEST COAST OF HAINAN ISLAND. INTENSITY GUIDANCE INDICATES MODERATE DEVELOPMENT TO NEAR TROPICAL STORM STRENGTH WHILE OVER THE GULF OF TONKIN WITH A SHARP DROP IN INTENSITY AFTERWARDS.

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