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JTWC IS ISSUING 6 HOURLY WARNINGS AND 3 HOURLY SATELLITE BULLETINS ON 09W
WESTERN PACIFIC: TY 09W(BAVI). WARNING 31 ISSUED BY JTWC @ 08/1500 UTC
TC WARNING GRAPHIC
PROGNOSTIC REASONING
WDPN31 PGTW 081500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (BAVI) WARNING NR 031//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 17.3N 131.8E
INITIAL INTENSITY: 125 KTS
GEOGRAPHIC REFERENCE: 595 NM SOUTH-SOUTHEAST OF KADENA AB
MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 12 KTS
SIGNIFICANT WAVE HEIGHT: 50 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON
09W (BAVI) ATTEMPTING TO UNDERGO ANOTHER EYEWALL REPLACEMENT CYCLE
(ERC) WITH CLEAR SEPARATION BETWEEN THE INNER-CORE AND A VERY LARGE
SECONDARY EYEWALL, PARTICULARLY WITHIN THE NORTHERN SEMICIRCLE. IN
RESPONSE TO THE ERC, THE OVERALL CONVECTIVE STRUCTURE HAS CLEARLY
DEGRADED OVER THE PAST 6 HOURS AND HAS CAUSED A LOWERING IN
INTENSITY. THE ERC WAS CAPTURED WELL BY THE 080913Z SSMIS 37 GHZ
MICROWAVE IMAGE WHICH REVEALED A WIDE MOAT FEATURE SEPARATING THE
TWO EYEWALLS. THE INNER EYEWALL DOES APPEAR TO BE RESTRUCTURING AT
AROUND 081400Z, SUGGESTING THAT THE ERC MAY NOT BE ABLE TO ENTIRELY
COMPLETE. A 080910Z RADARSAT-2 SAR IMAGE SHOWED A VMAX PEAK OF 126
KTS WITHIN THE NORTHERN PORTION OF THE EYEWALL AND AN R64 OF OVER
100 NM FROM THE CENTER IN ALL QUADRANTS. THE INITIAL INTENSITY OF
125 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE SAR DATA
ALONG WITH THE AGENCY DVORAK AND CIMSS INTENSITY ESTIMATES LISTED
BELOW. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON
THE EYE IN ANIMATED EIR IMAGERY. ENVIRONMENTAL ANALYSIS INDICATES
THAT 09W REMAINS IN A MARGINALLY FAVORABLE ENVIRONMENT
CHARACTERIZED BY STRONG RADIAL OUTFLOW ALOFT AND WARM (29-30 C) SEA
SURFACE TEMPERATURES OFFSET BY MODERATE TO HIGH (20-25 KTS)
NORTHEASTERLY VERTICAL WIND SHEAR AND SLIGHT DRY AIR INTRUSION.
INITIAL WIND RADII BASIS: 080910Z RADARSAT-2 SAR DATA
CURRENT STEERING MECHANISM: A COMBINED STEERING INFLUENCE FROM THE
WESTERN EXTENSION OF A SUBTROPICAL RIDGE (STR) POSITIONED TO THE
NORTHEAST AND THE SOUTHWESTERN EXTENSION OF A SEPARATE STR CENTERED
OVER SOUTHERN JAPAN.
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T6.5 - 127 KTS
RJTD: T6.5 - 127 KTS
RCTP: T6.5 - 127 KTS
KNES: T6.5 - 127 KTS
CIMSS SATCON: 137 KTS AT 081200Z
CIMSS ADT: 112 KTS AT 081200Z
CIMSS AIDT: 114 KTS AT 081200Z
CIMSS D-MINT: 136 KTS AT 080914Z
CIMSS D-PRINT: 123 KTS AT 081200Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
VWS: 20-25 KTS
SST: 29-30 CELSIUS
OUTFLOW: STRONG RADIAL
OTHER FACTORS: SLOT OF RELATIVELY DRY AIR WRAPPING INTO THE CORE
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: 09W IS FORECAST TO BEGIN TRACKING
NORTHWESTWARD AS THE STR THAT IS CURRENTLY POSITIONED OVER SOUTHERN
JAPAN MERGES WITH THE STR THAT IS SITUATED TO THE NORTHEAST OF 09W
OVER THE NEXT 6-12 HOURS. A NORTHWESTWARD TRACK IS THEN EXPECTED TO
PERSIST THROUGH TAU 96 AS 09W TRACKS ALONG THE SOUTHWESTERN
PERIPHERY OF THE RESULTING STR. A PASSAGE OVER THE YAEYAMA ISLANDS
IS FORECAST TO OCCUR JUST BEFORE TAU 60 AS THE SYSTEM CONTINUES TO
HEAD TOWARD THE EASTERN COAST OF CHINA. A FINAL LANDFALL IS
FORECAST TO TAKE PLACE SOON AFTER TAU 72 NEAR WENZHOU, CHINA.
THROUGHOUT THE TRACK LEADING UP TO THE FINAL LANDFALL, THE WIND
FIELD OF 09W IS EXPECTED TO REMAIN VERY LARGE WITH GALE-FORCE WINDS
EXTENDING UP TO 300 NM FROM THE CENTER. 09W WILL THEN TRACK FURTHER
INLAND INTO MAINLAND CHINA THROUGH TAU 96 BEFORE MAKING A NORTHWARD
TURN AS THE SYSTEM ATTEMPTS TO ROUND THE WESTERN EXTENT OF THE STR.
IN TERMS OF INTENSITY, 09W IS FORECAST TO CONTINUE SLIGHTLY
WEAKENING THROUGH TAU 12 UNDER THE INFLUENCE OF THE MODERATE
NORTHEASTERLY VERTICAL WIND SHEAR AND POTENTIAL EYEWALL REPLACEMENT
CYCLE. FROM TAU 24 THROUGH TAU 48, THE INTENSITY IS EXPECTED TO
MORE OR LESS BE MAINTAINED AS SHEAR DROPS TO BELOW 15 KTS. NEAR TAU
60, 09W IS EXPECTED TO ENTER AN AREA OF MUCH LOWER OCEAN HEAT
CONTENT (BELOW 25 KJ), TRIGGERING ANOTHER BOUT OF WEAKENING AS THE
SYSTEM APPROACHES THE COAST OF CHINA. AFTER LANDFALL, TERRAIN
INTERACTION WILL CAUSE THE VORTEX TO RAPIDLY DETERIORATE WITH
DISSIPATION FORECAST TO OCCUR AROUND TAU 120, WEST OF SHANGHAI.
MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT THROUGH TAU 72 WITH NO SIGNIFICANT OUTLIERS AND A
CROSS-TRACK SPREAD OF AROUND 100 NM. THE EC-AIFS AND EXPERIMENTAL
GOOGLE DEEPMIND ARE NOTABLY ON THE EASTERN END OF THE GUIDANCE
ENVELOPE, SUGGESTING A TRACK DIRECTLY OVER ISHIGAKIJIMA WHILE THE
PHYSICS-BASED MODELS TRACK THE VORTEX CLOSER TO THE NORTHERN TIP OF
TAIWAN. AFTER TAU 72, THE CROSS-TRACK SPREAD THEN OPENS UP TO ABOUT
280 NM AT TAU 120. THE JTWC TRACK FORECAST IS PLACED CLOSE TO THE
MULTI-MODEL CONSENSUS THROUGH TAU 72 WITH HIGH CONFIDENCE AND THEN
CLOSER TO THE GOOGLE DEEPMIND THROUGH TAU 120 WITH MEDIUM
CONFIDENCE. INTENSITY GUIDANCE AGREES ON GRADUAL WEAKENING THROUGH
TAU 60 FOLLOWED BY A MORE RAPID RATE OF WEAKENING AFTERWARD WITH NO
SIGNIFICANT VARIATION BETWEEN THE RELIABLE INTENSITY GUIDANCE. THE
JTWC INTENSITY FORECAST IS PLACED CLOSE TO THE CONSENSUS WITH
OVERALL MEDIUM CONFIDENCE DUE TO INHERENT UNCERTAINTIES REVOLVING
AROUND THE POTENTIAL EYEWALL REPLACEMENT CYCLE.
FORECAST CONFIDENCE:
TRACK 00-72 HR: HIGH
TRACK 72-120 HR: MEDIUM
INTENSITY 00-72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//
NNNN
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (BAVI) WARNING NR 031//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 17.3N 131.8E
INITIAL INTENSITY: 125 KTS
GEOGRAPHIC REFERENCE: 595 NM SOUTH-SOUTHEAST OF KADENA AB
MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 12 KTS
SIGNIFICANT WAVE HEIGHT: 50 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON
09W (BAVI) ATTEMPTING TO UNDERGO ANOTHER EYEWALL REPLACEMENT CYCLE
(ERC) WITH CLEAR SEPARATION BETWEEN THE INNER-CORE AND A VERY LARGE
SECONDARY EYEWALL, PARTICULARLY WITHIN THE NORTHERN SEMICIRCLE. IN
RESPONSE TO THE ERC, THE OVERALL CONVECTIVE STRUCTURE HAS CLEARLY
DEGRADED OVER THE PAST 6 HOURS AND HAS CAUSED A LOWERING IN
INTENSITY. THE ERC WAS CAPTURED WELL BY THE 080913Z SSMIS 37 GHZ
MICROWAVE IMAGE WHICH REVEALED A WIDE MOAT FEATURE SEPARATING THE
TWO EYEWALLS. THE INNER EYEWALL DOES APPEAR TO BE RESTRUCTURING AT
AROUND 081400Z, SUGGESTING THAT THE ERC MAY NOT BE ABLE TO ENTIRELY
COMPLETE. A 080910Z RADARSAT-2 SAR IMAGE SHOWED A VMAX PEAK OF 126
KTS WITHIN THE NORTHERN PORTION OF THE EYEWALL AND AN R64 OF OVER
100 NM FROM THE CENTER IN ALL QUADRANTS. THE INITIAL INTENSITY OF
125 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE SAR DATA
ALONG WITH THE AGENCY DVORAK AND CIMSS INTENSITY ESTIMATES LISTED
BELOW. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON
THE EYE IN ANIMATED EIR IMAGERY. ENVIRONMENTAL ANALYSIS INDICATES
THAT 09W REMAINS IN A MARGINALLY FAVORABLE ENVIRONMENT
CHARACTERIZED BY STRONG RADIAL OUTFLOW ALOFT AND WARM (29-30 C) SEA
SURFACE TEMPERATURES OFFSET BY MODERATE TO HIGH (20-25 KTS)
NORTHEASTERLY VERTICAL WIND SHEAR AND SLIGHT DRY AIR INTRUSION.
INITIAL WIND RADII BASIS: 080910Z RADARSAT-2 SAR DATA
CURRENT STEERING MECHANISM: A COMBINED STEERING INFLUENCE FROM THE
WESTERN EXTENSION OF A SUBTROPICAL RIDGE (STR) POSITIONED TO THE
NORTHEAST AND THE SOUTHWESTERN EXTENSION OF A SEPARATE STR CENTERED
OVER SOUTHERN JAPAN.
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T6.5 - 127 KTS
RJTD: T6.5 - 127 KTS
RCTP: T6.5 - 127 KTS
KNES: T6.5 - 127 KTS
CIMSS SATCON: 137 KTS AT 081200Z
CIMSS ADT: 112 KTS AT 081200Z
CIMSS AIDT: 114 KTS AT 081200Z
CIMSS D-MINT: 136 KTS AT 080914Z
CIMSS D-PRINT: 123 KTS AT 081200Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
VWS: 20-25 KTS
SST: 29-30 CELSIUS
OUTFLOW: STRONG RADIAL
OTHER FACTORS: SLOT OF RELATIVELY DRY AIR WRAPPING INTO THE CORE
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: 09W IS FORECAST TO BEGIN TRACKING
NORTHWESTWARD AS THE STR THAT IS CURRENTLY POSITIONED OVER SOUTHERN
JAPAN MERGES WITH THE STR THAT IS SITUATED TO THE NORTHEAST OF 09W
OVER THE NEXT 6-12 HOURS. A NORTHWESTWARD TRACK IS THEN EXPECTED TO
PERSIST THROUGH TAU 96 AS 09W TRACKS ALONG THE SOUTHWESTERN
PERIPHERY OF THE RESULTING STR. A PASSAGE OVER THE YAEYAMA ISLANDS
IS FORECAST TO OCCUR JUST BEFORE TAU 60 AS THE SYSTEM CONTINUES TO
HEAD TOWARD THE EASTERN COAST OF CHINA. A FINAL LANDFALL IS
FORECAST TO TAKE PLACE SOON AFTER TAU 72 NEAR WENZHOU, CHINA.
THROUGHOUT THE TRACK LEADING UP TO THE FINAL LANDFALL, THE WIND
FIELD OF 09W IS EXPECTED TO REMAIN VERY LARGE WITH GALE-FORCE WINDS
EXTENDING UP TO 300 NM FROM THE CENTER. 09W WILL THEN TRACK FURTHER
INLAND INTO MAINLAND CHINA THROUGH TAU 96 BEFORE MAKING A NORTHWARD
TURN AS THE SYSTEM ATTEMPTS TO ROUND THE WESTERN EXTENT OF THE STR.
IN TERMS OF INTENSITY, 09W IS FORECAST TO CONTINUE SLIGHTLY
WEAKENING THROUGH TAU 12 UNDER THE INFLUENCE OF THE MODERATE
NORTHEASTERLY VERTICAL WIND SHEAR AND POTENTIAL EYEWALL REPLACEMENT
CYCLE. FROM TAU 24 THROUGH TAU 48, THE INTENSITY IS EXPECTED TO
MORE OR LESS BE MAINTAINED AS SHEAR DROPS TO BELOW 15 KTS. NEAR TAU
60, 09W IS EXPECTED TO ENTER AN AREA OF MUCH LOWER OCEAN HEAT
CONTENT (BELOW 25 KJ), TRIGGERING ANOTHER BOUT OF WEAKENING AS THE
SYSTEM APPROACHES THE COAST OF CHINA. AFTER LANDFALL, TERRAIN
INTERACTION WILL CAUSE THE VORTEX TO RAPIDLY DETERIORATE WITH
DISSIPATION FORECAST TO OCCUR AROUND TAU 120, WEST OF SHANGHAI.
MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT THROUGH TAU 72 WITH NO SIGNIFICANT OUTLIERS AND A
CROSS-TRACK SPREAD OF AROUND 100 NM. THE EC-AIFS AND EXPERIMENTAL
GOOGLE DEEPMIND ARE NOTABLY ON THE EASTERN END OF THE GUIDANCE
ENVELOPE, SUGGESTING A TRACK DIRECTLY OVER ISHIGAKIJIMA WHILE THE
PHYSICS-BASED MODELS TRACK THE VORTEX CLOSER TO THE NORTHERN TIP OF
TAIWAN. AFTER TAU 72, THE CROSS-TRACK SPREAD THEN OPENS UP TO ABOUT
280 NM AT TAU 120. THE JTWC TRACK FORECAST IS PLACED CLOSE TO THE
MULTI-MODEL CONSENSUS THROUGH TAU 72 WITH HIGH CONFIDENCE AND THEN
CLOSER TO THE GOOGLE DEEPMIND THROUGH TAU 120 WITH MEDIUM
CONFIDENCE. INTENSITY GUIDANCE AGREES ON GRADUAL WEAKENING THROUGH
TAU 60 FOLLOWED BY A MORE RAPID RATE OF WEAKENING AFTERWARD WITH NO
SIGNIFICANT VARIATION BETWEEN THE RELIABLE INTENSITY GUIDANCE. THE
JTWC INTENSITY FORECAST IS PLACED CLOSE TO THE CONSENSUS WITH
OVERALL MEDIUM CONFIDENCE DUE TO INHERENT UNCERTAINTIES REVOLVING
AROUND THE POTENTIAL EYEWALL REPLACEMENT CYCLE.
FORECAST CONFIDENCE:
TRACK 00-72 HR: HIGH
TRACK 72-120 HR: MEDIUM
INTENSITY 00-72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//
NNNN
JTWC TREND
JTWC TREND
Ensemble Track Ellipses
@08 1256UTC
09W (BAVI) ATTEMPTING TO UNDERGO ANOTHER EYEWALL REPLACEMENT CYCLE (ERC) WITH CLEAR SEPARATION BETWEEN THE INNER-CORE AND A VERY LARGE SECONDARY EYEWALL.
@08 1256UTC
Radius of Maximum Wind (RMW)
Platform: RCM-1
Acquisition Date: 2026-07-08 09:20:17 UTC
Storm Name: WP092026 / BAVI
Storm ID: WP09
Storm Center Longitude: 132.431
Storm Center Latitude: 17.183
Incidence Angle (Degrees): 42.966
Quadrant 1 NE VMax (kts): 114.96
Quadrant 2 SE VMax (kts): 104.26
Quadrant 3 SW VMax (kts): 106.19
Quadrant 4 NW VMax (kts): 110.91
RMax (nmi): 18.00 - 20.00
Acquisition Date: 2026-07-08 09:20:17 UTC
Storm Name: WP092026 / BAVI
Storm ID: WP09
Storm Center Longitude: 132.431
Storm Center Latitude: 17.183
Incidence Angle (Degrees): 42.966
Quadrant 1 NE VMax (kts): 114.96
Quadrant 2 SE VMax (kts): 104.26
Quadrant 3 SW VMax (kts): 106.19
Quadrant 4 NW VMax (kts): 110.91
RMax (nmi): 18.00 - 20.00
DVORAK ANALYSIS
TPPN10 PGTW 081513
A. TYPHOON 09W (BAVI)
B. 08/1430Z
C. 17.50N
D. 131.39E
E. FIVE/GK2A
F. T5.5/6.5/W1.0/24HRS STT: S0.0/03HRS
G. IR/EIR
H. REMARKS: 34A/PBO LARGE EYE/ANMTN. WMG EYE SURROUNDED BY LG
YIELDS AN E# OF 5.0. ADDED 0.5 EYE ADJUSTMENT FOR LG, TO YIELD A
DT OF 5.5. MET AND PT AGREE. DBO DT.
I. ADDITIONAL POSITIONS:
08/0920Z 17.17N 132.42E SARI
DE LA ROSA
A. TYPHOON 09W (BAVI)
B. 08/1430Z
C. 17.50N
D. 131.39E
E. FIVE/GK2A
F. T5.5/6.5/W1.0/24HRS STT: S0.0/03HRS
G. IR/EIR
H. REMARKS: 34A/PBO LARGE EYE/ANMTN. WMG EYE SURROUNDED BY LG
YIELDS AN E# OF 5.0. ADDED 0.5 EYE ADJUSTMENT FOR LG, TO YIELD A
DT OF 5.5. MET AND PT AGREE. DBO DT.
I. ADDITIONAL POSITIONS:
08/0920Z 17.17N 132.42E SARI
DE LA ROSA
Digital Dvorak
WESTERN PACIFIC: INVEST 97W.
