Western Pacific Tropical Weather Discussion

The West Pacific has no National Hurricane Center discussion. The equivalent products are issued by the Joint Typhoon Warning Center (JTWC): the basin-wide Significant Tropical Weather Advisory and the prognostic reasoning behind each active warning.

Significant Tropical Weather Advisory (JTWC ABPW10)

Issued: 2026-09-19 06:00:00 UTC

ABPW10 PGTW 190600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND SOUTH 
PACIFIC OCEANS/190600Z-200600ZSEP2026//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/190151ZSEP2026//
AMPN/REF A IS A TROPICAL CYCLONE WARNING.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
   A. TROPICAL CYCLONE SUMMARY:
      (1) AT 19SEP26 0000Z, TYPHOON 24W (DUJUAN) WAS LOCATED NEAR 
26.2N 139.7E, APPROXIMATELY 121 NM NORTHWEST OF IWO TO, AND HAD 
TRACKED WEST- NORTHWESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. 
MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 65 KNOTS GUSTING TO 
80 KNOTS. SEE REF A (WTPN31 PGTW 190300) FOR FURTHER DETAILS.
      (2) NO OTHER TROPICAL CYCLONES.
   B. TROPICAL DISTURBANCE SUMMARY: NONE.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
   A. TROPICAL CYCLONE SUMMARY: NONE.
   B. TROPICAL DISTURBANCE SUMMARY: NONE.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.//

Prognostic Reasoning for Active Systems

Typhoon Dujuan — 75 mph (1-minute sustained)

Issued: 2026-09-19 15:00:00 UTC

WDPN31 PGTW 191500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 24W (DUJUAN) WARNING NR 017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.8N 138.2E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 456 NM SOUTH OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 11 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS SPIRAL 
BANDS OF DEEP CONVECTION WRAPPING INTO THE COMPACT INNER CORE OF 
TYPHOON (TY) 24W (DUJUAN). DRY AIR ENTRAINMENT IS PRESENT NEARLY FULLY 
ENCOMPASSING THE BROADER CIRCULATION, SIGNIFICANTLY IMPACTING THE 
ABILITY OF THE SYSTEM TO INTENSIFY. THE INITIAL POSITION IS PLACED 
WITH MEDIUM CONFIDENCE BASED ON THE ANALYSIS OF LOW-LEVEL CLOUDS AND 
EXTRAPOLATION FROM A 190858Z RCM-2 SAR PASS. THE INITIAL INTENSITY OF 
65 KTS IS ALSO ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE FUSION OF 
CONGRUENT SATELLITE DVORAK FIXES AND AUTOMATED OBJECTIVE ESTIMATES 
LISTED BELOW. A MARGINALLY FAVORABLE ENVIRONMENT IS CHARACTERIZED BY 
AN EXCELLENT POLEWARD EXHAUST CHANNEL AND BENIGN VERTICAL WIND SHEAR 
(VWS) OF 10-15 KTS IN TANDEM WITH CONDUCIVE SEA SURFACE TEMPERATURES 
(SST) OF 28-29 C.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) CENTERED TO THE
NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T4.0 - 65 KTS
   CIMSS SATCON: 64 KTS AT 190839Z
   CIMSS ADT: 51 KTS AT 191140Z
   CIMSS AIDT: 46 KTS AT 191140Z
   CIMSS D-MINT: 67 KTS AT 190839Z
   CIMSS D-PRINT: 63 KTS AT 191210Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE 
FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TY DUJUAN IS PROPAGATING ALONG THE SOUTHWESTERN 
PERIPHERY OF A SUBTROPICAL RIDGE (STR) ANCHORED TO THE NORTHEAST. 
THE CYCLONE IS FORECAST TO ROUND THE STR AXIS WITHIN THE NEXT 24 
HOURS, INITIATING A RECURVATURE VECTOR TOWARD THE NORTHEAST THAT 
PLACES THE SWATH OF STRONGEST WINDS TO THE SOUTHEAST OF MAINLAND 
JAPAN. THROUGH TAU 36, THE MAXIMUM SUSTAINED WIND SPEED WILL HOVER 
NEAR 65 KTS WITHIN A MARGINALLY CONDUCIVE SYNOPTIC ENVIRONMENT. SLIGHT 
DYNAMIC RE-DEEPENING IS FEASIBLE SHORTLY AFTER, ASSISTED BY AN 
ACCELERATED POLEWARD OUTFLOW FLUX AND DIRECT TRANSIT OVER THE WARM 
WATERS OF THE KUROSHIO CURRENT. DYNAMICAL GLOBAL MODEL FIELDS INDICATE 
THE POTENTIAL FOR THE SYSTEM TO BRIEFLY COCOON FROM THE SURROUNDING 
DRY AIR. AROUND TAU 60, RAPIDLY COOLING SEA SURFACE TEMPERATURES, 
INCREASING ENTRAINMENT OF DRY TROPOSPHERIC AIR, AND SIGNIFICANTLY 
ESCALATING VWS WILL DEPRESS THE VORTEX INTO A TERMINAL WEAKENING 
PHASE. EXTRATROPICAL TRANSITION (ETT) IS ANTICIPATED TO ENGAGE, WITH 
THE ACCELERATING SYSTEM COMPLETING THE TRANSITION BY TAU 96 AS IT 
POSITIONS ITSELF UNDERNEATH POWERFUL UPPER-LEVEL WESTERLY JET STREAM 
ALOFT.

MODEL DISCUSSION: DYNAMICAL TRACK GUIDANCE SOLUTIONS REVEAL GOOD 
AGREEMENT, CHARACTERIZED BY AN IMPROVED 40 NM CROSS-TRACK SPREAD AT 
THE CLOSEST POINT OF APPROACH (CPA) TO YOKOSUKA, JAPAN. ALONG-TRACK 
SPREAD RISES TO 110 NM, WHILE THE OFFICIAL JTWC TRACK IS POSITIONED 
CLOSE TO THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE. REGARDING 
INTENSITY, THE GENERAL ENVELOPE RESOLVES TYPHOON-STRENGTH RETENTION 
OVER THE NEXT 48 HOURS. DIVERGENCE EXPANDS SUBSTANTIALLY AT TAU 60, 
OPENING TO A 40 KTS SPREAD SPANNING 45 TO 85 KTS. STATISTICAL-
DYNAMICAL SCENARIOS PROJECT CONTINUOUS WEAKENING, WHILE MOST OF THE 
DYNAMICAL SOLUTIONS (HAFS, COAMPS-TC, AND GFS) DEPICT A SHORT-LIVED 
RE-INTENSIFICATION PHASE REFLECTED IN THE OFFICIAL JTWC PROJECTION 
REACHING A PEAK OF 75 KTS AROUND TAU 60. ACCORDINGLY, THE OFFICIAL 
INTENSITY OUTLOOK CONVERGES NEAR THE MULTI-MODEL CONSENSUS AND IS 
ASSESSED WITH MEDIUM CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   TRACK 72-120 HR: HIGH
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//