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JTWC IS ISSUING 6 HOURLY WARNINGS AND 3 HOURLY SATELLITE BULLETINS ON 09W
WESTERN PACIFIC: STY 09W(BAVI). WARNING 18 ISSUED BY JTWC @ 05/0900 UTC
TC WARNING GRAPHIC
PROGNOSTIC REASONING
WDPN31 PGTW 050900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 09W (BAVI) WARNING NR
018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 13.4N 148.1E
INITIAL INTENSITY: 145 KTS
GEOGRAPHIC REFERENCE: 188 NM EAST OF ANDERSEN AFB
MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 09 KTS
SIGNIFICANT WAVE HEIGHT: 48 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN EXTREMELY
POWERFUL SUPER TYPHOON (STY) STEADILY APPROACHING THE MARIANA
ISLANDS. AFTER A BRIEF JOG TO THE NORTH, STY BAVI HAS RESUMED ITS
WEST-NORTHWEST MOTION AT A HIGHER RATE OF 9 KTS. THE 3-HOURLY JT
UPDATED POSITION PRODUCT (JTUP) WILL BE PRODUCED BEGINNING AT
040900Z. THE COLD CLOUD TOPS ASSOCIATED WITH THE CENTRAL DENSE
OVERCAST HAVE SIGNIFICANTLY COOLED, WITH A THICK RING OF THE CMG
SHADE IN THE BD CURVE-ENHANCED INFRARED IMAGE NEARLY ENCIRCLING THE
EYE. POSSESSING A DIAMETER OF 25 NM, THE EYE HAS CLEARED OUT, AND
GALE-FORCE WINDS NOW EXTEND 170 NM OUTWARD FROM THE CENTER. THE
PERFECTLY CIRCULAR EYE IS VISIBLE ON THE PGUA WSR-88D RADAR, AND
RAIN BANDS ARE SWEEPING OVER THE SOUTHERN MARIANA ISLANDS FROM
NORTH TO SOUTH. OBSERVATIONS FROM SAIPAN AND GUAM INDICATE THAT
GUSTS HAVE INCREASED TO NEAR 40 KTS. RECENT MICROWAVE RADIOMETER
PASSES FROM AMSR2 AT 050336Z AND SSMIS AT 050553Z PROVIDED EVIDENCE
THAT AN EYEWALL REPLACEMENT CYCLE (ERC) IS CURRENTLY NOT UNDERWAY
BY SHOWING IN THE 37 GHZ IMAGE MULTIPLE INCOMPLETE RINGS SPIRALING
INTO THE CENTER. HOWEVER, SUCH A CONVECTIVE STRUCTURE IS QUITE
SUSCEPTIBLE TO ADDITIONAL ERC EVENTS, AND THE FULL MODEL FROM THE
CIMSS MPERC ALGORITHM ESTIMATES A 62 PERCENT CHANCE OF ERC ONSET.
THE ENVIRONMENT IS HIGHLY CONDUCIVE FOR INTENSIFICATION,
CHARACTERIZED BY HIGH OCEAN HEAT CONTENT (OHC) OF 125 KJ PER SQUARE
CM, LOW VERTICAL WIND SHEAR (VWS), ABUNDANT DEEP-LAYER MOISTURE,
AND EXCELLENT RADIAL OUTFLOW. THE INITIAL POSITION IS ASSESSED WITH
HIGH CONFIDENCE BASED ON THE SHARPLY DEFINED EYE ON VISIBLE
HIMAWARI-9 IMAGERY. THE INITIAL INTENSITY IS RAISED TO 145 KTS WITH
HIGH CONFIDENCE BASED ON THE SUBSTANTIAL IMPROVEMENTS DISCUSSED
ABOVE AND A BLEND OF T7.0-7.5 SUBJECTIVE DVORAK FIXES FROM JTWC,
KNES, RJTD, AND RCTP.
INITIAL WIND RADII BASIS: SCATTEROMETER DATA
CURRENT STEERING MECHANISM: EASTERN EXTENSION OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTER NEAR OKINAWA
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T7.0 - 140 KTS
RJTD: T7.5 - 155 KTS
RCTP: T7.0 - 140 KTS
KNES: T7.0 - 140 KTS
CIMSS SATCON: 140 KTS AT 050600Z
CIMSS ADT: 137 KTS AT 050600Z
CIMSS AIDT: 137 KTS AT 050600Z
CIMSS D-MINT: 140 KTS AT 050553Z
CIMSS D-PRINT: 131 KTS AT 050600Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
VWS: 10-15 KTS
SST: 29-30 CELSIUS
OUTFLOW: STRONG RADIAL
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THE FORECAST TRACK AT THE TIME OF
PASSAGE THROUGH THE MARIANA ISLANDS HAS SHIFTED 15 NM POLEWARD, AND
THE NEAR-TERM INTENSITY FORECAST HAS BEEN INCREASED BY 10 KTS.
FORECAST DISCUSSION: STY 09W HAS BEGUN A FASTER RATE OF MOTION
TOWARDS THE WEST-NORTHWEST, WHICH WILL CONTINUE TO TAU 36 AS IT
APPROACHES A STRONG STR CENTERED OVER THE RYUKYU ISLANDS. THE RIDGE
WILL FLATTEN THE TRACK TO BE MORE WESTERLY FROM TAU 36 TO TAU 72.
AT THE END OF THE FORECAST PERIOD, THE SYSTEM WILL BEGIN TO ROUND
THE SOUTHWEST PERIPHERY OF THE STR AND TURN TOWARDS THE NORTHWEST.
THE ENVIRONMENT IS BECOMING EVEN MORE CONDUCIVE FOR
INTENSIFICATION. AN UPPER-LEVEL TROUGH UPSTREAM OF THE TYPHOON IS
ACTIVELY DRAWING MASS FROM THE TYPHOON AND ENHANCING WESTWARD AND
POLEWARD OUTFLOW. FURTHERMORE, STY 09W WILL MOVE OVER A POOL OF
HIGHER OHC IN EXCESS OF 150 KJ PER SQUARE CM AND WARMER SEA SURFACE
TEMPERATURE (SST) OF 30-31 DEGREES CELSIUS, WHILE THE UPPER-LEVEL
DIVERGENCE INCREASES AS A RESULT OF THE TROUGH. THESE FACTORS WILL
FUEL ADDITIONAL NEAR-TERM INTENSIFICATION AS THE LARGE CIRCULATION
APPROACHES AND PASSES THE SOUTHERN MARIANA ISLANDS. THE ONLY
INHIBITING FACTOR IS ERC POTENTIAL, THE TIMING, DURATION, AND
IMPACT OF WHICH CANNOT BE RELIABLY PREDICTED WITH HIGH FIDELITY.
SLOW WEAKENING WILL COMMENCE AT TAU 48 DUE TO INCREASING VWS AND
POSSIBLE ERC EXPLICITLY DEPICTED BY HAFS-A. AT TAUS 96 AND 120, THE
SYSTEM WILL WEAKEN MORE QUICKLY WHEN IT TRAVERSES OVER LOWER OHC IN
THE FACE OF MODERATE TO HIGH VWS. THE CIRCULATION OF 09W IS
EXPANDING, AND GALE-FORCE WINDS WILL EXTEND OUTWARD TO NEARLY 300
NM FROM THE CENTER AT TAU 120. IMPACTS WILL EXTEND FAR FROM THE
CENTER.
MODEL DISCUSSION: DUE TO A NORTHWARD JOG WITHIN THE PAST SIX HOURS,
THE GUIDANCE ENVELOPE HAS SHIFTED NORTHWARD, NECESSITATING A SLIGHT
POLEWARD ADJUSTMENT OF THE JTWC FORECAST TRACK FROM TAU 12 TO TAU
36. THE MODEL TRACKERS REMAIN TIGHTLY CLUSTERED TO TAU 72 WITH A
CROSS-TRACK SPREAD OF 110 NM. THE SPREAD INCREASES TO 225 NM AT TAU
120 WITH NAVGEM AND THE AI MODELS ON THE POLEWARD SIDE AND GALWEM
AND HWRF ON THE EQUATORWARD SIDE. NEARLY ALL OF THE GUIDANCE TAKES
THE STORM CENTER BETWEEN TINIAN AND ROTA. THE JTWC TRACK IS LAID
WITH HIGH CONFIDENCE NEAR THE MULTI-MODEL CONSENSUS, WHICH IS
CLOSEST TO JGSM, GFS, AND ECMWF. STY BAVI CONTINUES TO PERFORM
EXCEPTIONALLY WELL, INTENSIFYING TO LEVELS ABOVE THE SOLUTIONS FROM
NEARLY ALL OF THE RELIABLE INTENSITY AIDS. HAFS-A REMAINS THE MOST
AGGRESSIVE MEMBER AND DEPICTS A PEAK OF 155-160 KTS. GIVEN RECENT
TRENDS AND THE OPTIMAL ENVIRONMENT, A HIGHER PEAK THAN FORECAST IS
WELL WITHIN THE REALM OF POSSIBILITY. HAFS-A, COAMPS-TC, AND THE
EXPERIMENTAL GOOGLE DEEPMIND MODEL DEPICT A GRADUAL WEAKENING TREND
BY TAU 24-48 AND A STEADIER RATE BY 72-96. THE JTWC INTENSITY
FORECAST IS AT THE UPPER END OF THE RELIABLE GUIDANCE AND FOLLOWS
THE AVERAGE RATE OF DECLINE DEPICTED BY THESE MODELS.
FORECAST CONFIDENCE:
TRACK 00-72 HR: HIGH
TRACK 72-120 HR: HIGH
INTENSITY 00-72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//
NNNN
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 09W (BAVI) WARNING NR
018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 13.4N 148.1E
INITIAL INTENSITY: 145 KTS
GEOGRAPHIC REFERENCE: 188 NM EAST OF ANDERSEN AFB
MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 09 KTS
SIGNIFICANT WAVE HEIGHT: 48 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN EXTREMELY
POWERFUL SUPER TYPHOON (STY) STEADILY APPROACHING THE MARIANA
ISLANDS. AFTER A BRIEF JOG TO THE NORTH, STY BAVI HAS RESUMED ITS
WEST-NORTHWEST MOTION AT A HIGHER RATE OF 9 KTS. THE 3-HOURLY JT
UPDATED POSITION PRODUCT (JTUP) WILL BE PRODUCED BEGINNING AT
040900Z. THE COLD CLOUD TOPS ASSOCIATED WITH THE CENTRAL DENSE
OVERCAST HAVE SIGNIFICANTLY COOLED, WITH A THICK RING OF THE CMG
SHADE IN THE BD CURVE-ENHANCED INFRARED IMAGE NEARLY ENCIRCLING THE
EYE. POSSESSING A DIAMETER OF 25 NM, THE EYE HAS CLEARED OUT, AND
GALE-FORCE WINDS NOW EXTEND 170 NM OUTWARD FROM THE CENTER. THE
PERFECTLY CIRCULAR EYE IS VISIBLE ON THE PGUA WSR-88D RADAR, AND
RAIN BANDS ARE SWEEPING OVER THE SOUTHERN MARIANA ISLANDS FROM
NORTH TO SOUTH. OBSERVATIONS FROM SAIPAN AND GUAM INDICATE THAT
GUSTS HAVE INCREASED TO NEAR 40 KTS. RECENT MICROWAVE RADIOMETER
PASSES FROM AMSR2 AT 050336Z AND SSMIS AT 050553Z PROVIDED EVIDENCE
THAT AN EYEWALL REPLACEMENT CYCLE (ERC) IS CURRENTLY NOT UNDERWAY
BY SHOWING IN THE 37 GHZ IMAGE MULTIPLE INCOMPLETE RINGS SPIRALING
INTO THE CENTER. HOWEVER, SUCH A CONVECTIVE STRUCTURE IS QUITE
SUSCEPTIBLE TO ADDITIONAL ERC EVENTS, AND THE FULL MODEL FROM THE
CIMSS MPERC ALGORITHM ESTIMATES A 62 PERCENT CHANCE OF ERC ONSET.
THE ENVIRONMENT IS HIGHLY CONDUCIVE FOR INTENSIFICATION,
CHARACTERIZED BY HIGH OCEAN HEAT CONTENT (OHC) OF 125 KJ PER SQUARE
CM, LOW VERTICAL WIND SHEAR (VWS), ABUNDANT DEEP-LAYER MOISTURE,
AND EXCELLENT RADIAL OUTFLOW. THE INITIAL POSITION IS ASSESSED WITH
HIGH CONFIDENCE BASED ON THE SHARPLY DEFINED EYE ON VISIBLE
HIMAWARI-9 IMAGERY. THE INITIAL INTENSITY IS RAISED TO 145 KTS WITH
HIGH CONFIDENCE BASED ON THE SUBSTANTIAL IMPROVEMENTS DISCUSSED
ABOVE AND A BLEND OF T7.0-7.5 SUBJECTIVE DVORAK FIXES FROM JTWC,
KNES, RJTD, AND RCTP.
INITIAL WIND RADII BASIS: SCATTEROMETER DATA
CURRENT STEERING MECHANISM: EASTERN EXTENSION OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTER NEAR OKINAWA
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T7.0 - 140 KTS
RJTD: T7.5 - 155 KTS
RCTP: T7.0 - 140 KTS
KNES: T7.0 - 140 KTS
CIMSS SATCON: 140 KTS AT 050600Z
CIMSS ADT: 137 KTS AT 050600Z
CIMSS AIDT: 137 KTS AT 050600Z
CIMSS D-MINT: 140 KTS AT 050553Z
CIMSS D-PRINT: 131 KTS AT 050600Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
VWS: 10-15 KTS
SST: 29-30 CELSIUS
OUTFLOW: STRONG RADIAL
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THE FORECAST TRACK AT THE TIME OF
PASSAGE THROUGH THE MARIANA ISLANDS HAS SHIFTED 15 NM POLEWARD, AND
THE NEAR-TERM INTENSITY FORECAST HAS BEEN INCREASED BY 10 KTS.
FORECAST DISCUSSION: STY 09W HAS BEGUN A FASTER RATE OF MOTION
TOWARDS THE WEST-NORTHWEST, WHICH WILL CONTINUE TO TAU 36 AS IT
APPROACHES A STRONG STR CENTERED OVER THE RYUKYU ISLANDS. THE RIDGE
WILL FLATTEN THE TRACK TO BE MORE WESTERLY FROM TAU 36 TO TAU 72.
AT THE END OF THE FORECAST PERIOD, THE SYSTEM WILL BEGIN TO ROUND
THE SOUTHWEST PERIPHERY OF THE STR AND TURN TOWARDS THE NORTHWEST.
THE ENVIRONMENT IS BECOMING EVEN MORE CONDUCIVE FOR
INTENSIFICATION. AN UPPER-LEVEL TROUGH UPSTREAM OF THE TYPHOON IS
ACTIVELY DRAWING MASS FROM THE TYPHOON AND ENHANCING WESTWARD AND
POLEWARD OUTFLOW. FURTHERMORE, STY 09W WILL MOVE OVER A POOL OF
HIGHER OHC IN EXCESS OF 150 KJ PER SQUARE CM AND WARMER SEA SURFACE
TEMPERATURE (SST) OF 30-31 DEGREES CELSIUS, WHILE THE UPPER-LEVEL
DIVERGENCE INCREASES AS A RESULT OF THE TROUGH. THESE FACTORS WILL
FUEL ADDITIONAL NEAR-TERM INTENSIFICATION AS THE LARGE CIRCULATION
APPROACHES AND PASSES THE SOUTHERN MARIANA ISLANDS. THE ONLY
INHIBITING FACTOR IS ERC POTENTIAL, THE TIMING, DURATION, AND
IMPACT OF WHICH CANNOT BE RELIABLY PREDICTED WITH HIGH FIDELITY.
SLOW WEAKENING WILL COMMENCE AT TAU 48 DUE TO INCREASING VWS AND
POSSIBLE ERC EXPLICITLY DEPICTED BY HAFS-A. AT TAUS 96 AND 120, THE
SYSTEM WILL WEAKEN MORE QUICKLY WHEN IT TRAVERSES OVER LOWER OHC IN
THE FACE OF MODERATE TO HIGH VWS. THE CIRCULATION OF 09W IS
EXPANDING, AND GALE-FORCE WINDS WILL EXTEND OUTWARD TO NEARLY 300
NM FROM THE CENTER AT TAU 120. IMPACTS WILL EXTEND FAR FROM THE
CENTER.
MODEL DISCUSSION: DUE TO A NORTHWARD JOG WITHIN THE PAST SIX HOURS,
THE GUIDANCE ENVELOPE HAS SHIFTED NORTHWARD, NECESSITATING A SLIGHT
POLEWARD ADJUSTMENT OF THE JTWC FORECAST TRACK FROM TAU 12 TO TAU
36. THE MODEL TRACKERS REMAIN TIGHTLY CLUSTERED TO TAU 72 WITH A
CROSS-TRACK SPREAD OF 110 NM. THE SPREAD INCREASES TO 225 NM AT TAU
120 WITH NAVGEM AND THE AI MODELS ON THE POLEWARD SIDE AND GALWEM
AND HWRF ON THE EQUATORWARD SIDE. NEARLY ALL OF THE GUIDANCE TAKES
THE STORM CENTER BETWEEN TINIAN AND ROTA. THE JTWC TRACK IS LAID
WITH HIGH CONFIDENCE NEAR THE MULTI-MODEL CONSENSUS, WHICH IS
CLOSEST TO JGSM, GFS, AND ECMWF. STY BAVI CONTINUES TO PERFORM
EXCEPTIONALLY WELL, INTENSIFYING TO LEVELS ABOVE THE SOLUTIONS FROM
NEARLY ALL OF THE RELIABLE INTENSITY AIDS. HAFS-A REMAINS THE MOST
AGGRESSIVE MEMBER AND DEPICTS A PEAK OF 155-160 KTS. GIVEN RECENT
TRENDS AND THE OPTIMAL ENVIRONMENT, A HIGHER PEAK THAN FORECAST IS
WELL WITHIN THE REALM OF POSSIBILITY. HAFS-A, COAMPS-TC, AND THE
EXPERIMENTAL GOOGLE DEEPMIND MODEL DEPICT A GRADUAL WEAKENING TREND
BY TAU 24-48 AND A STEADIER RATE BY 72-96. THE JTWC INTENSITY
FORECAST IS AT THE UPPER END OF THE RELIABLE GUIDANCE AND FOLLOWS
THE AVERAGE RATE OF DECLINE DEPICTED BY THESE MODELS.
FORECAST CONFIDENCE:
TRACK 00-72 HR: HIGH
TRACK 72-120 HR: HIGH
INTENSITY 00-72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//
NNNN
JTWC TREND
JTWC TREND
RIPA Forecast
85 – 92 GHz Brightness Temperature @05/0815 UTC
Radius of Maximum Wind (RMW)
DVORAK ANALYSIS @ 05/0830 UTC
TPPN10 PGTW 050907
A. SUPER TYPHOON 09W (BAVI)
B. 05/0830Z
C. 13.58N
D. 147.67E
E. ONE/GK2A
F. T7.0/7.0/S0.0/24HRS STT: S0.0/03HRS
G. IR/EIR
H. REMARKS: 01A/PBO EYE/ANMTN. WMG EYE SURROUNDED BY W YIELDS AN E#
OF 6.0. ADDED 1.0 EYE ADJUSTMENT FOR W, TO YIELD A DT OF 7.0. MET
YIELDS 7.0. PT YIELDS 7.0. DBO DT.
I. ADDITIONAL POSITIONS:
05/0335Z 13.13N 148.53E AMS2
05/0553Z 13.42N 148.05E SSMS
THOMPSON
A. SUPER TYPHOON 09W (BAVI)
B. 05/0830Z
C. 13.58N
D. 147.67E
E. ONE/GK2A
F. T7.0/7.0/S0.0/24HRS STT: S0.0/03HRS
G. IR/EIR
H. REMARKS: 01A/PBO EYE/ANMTN. WMG EYE SURROUNDED BY W YIELDS AN E#
OF 6.0. ADDED 1.0 EYE ADJUSTMENT FOR W, TO YIELD A DT OF 7.0. MET
YIELDS 7.0. PT YIELDS 7.0. DBO DT.
I. ADDITIONAL POSITIONS:
05/0335Z 13.13N 148.53E AMS2
05/0553Z 13.42N 148.05E SSMS
THOMPSON
