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: 2026-08-22 15:00:00 UTC

ABPW10 PGTW 221500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND SOUTH 
PACIFIC OCEANS REISSUED/221500Z-230600ZAUG2026//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/221351ZAUG2026//
REF/B/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/221352ZAUG2026//
REF/C/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/2213513AUG2026//
NARR/REFS A, B AND C ARE TROPICAL CYCLONE WARNINGS.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
   A. TROPICAL CYCLONE SUMMARY:
      (1) AT 22AUG26 1200Z, TYPHOON 17W (SAUDEL) WAS LOCATED NEAR 
19.6N 144.8E, APPROXIMATELY 1025 NM EAST-SOUTHEAST OF KADENA AB, AND 
HAD TRACKED NORTHWESTWARD AT 14 KNOTS OVER THE PAST SIX HOURS. MAXIMUM 
SUSTAINED SURFACE WINDS WERE ESTIMATED AT 105 KNOTS GUSTING TO 130 
KNOTS. SEE REF A (WTPN31 PGTW 221500) FOR FURTHER DETAILS.
      (2) AT 22AUG26 1200Z, TROPICAL DEPRESSION 18W (NARRA) WAS 
LOCATED NEAR 21.0N 108.0E, APPROXIMATELY 118 NM EAST OF HANOI, 
VIETNAM, AND HAD TRACKED SOUTHWESTWARD AT 01 KNOTS OVER THE PAST SIX 
HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 30 KNOTS 
GUSTING TO 40 KNOTS. SEE REF B (WTPN32 PGTW 221500) FOR FURTHER 
DETAILS.
      (3) AT 22AUG26 1200Z, TROPICAL DEPRESSION 19W (NINETEEN) WAS 
LOCATED NEAR 12.2N 135.4E, APPROXIMATELY 543 NM WEST OF NAVSTA GUAM, 
AND HAD TRACKED NORTH-NORTHWESTWARD AT 09 KNOTS OVER THE PAST SIX 
HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 30 KNOTS 
GUSTING TO 40 KNOTS. SEE REF C (WTPN33 PGTW 221500) FOR FURTHER 
DETAILS.
      (4) NO OTHER TROPICAL CYCLONES.
   B. TROPICAL DISTURBANCE SUMMARY:
      (1) THE AREA OF CONVECTION (INVEST 94W) PREVIOUSLY LOCATED NEAR 
26.5N 123.7E IS NOW LOCATED NEAR 26.7N 122.6E, APPROXIMATELY 120 NM 
NORTH-NORTHEAST OF TAIPEI. THE SYSTEM IS CURRENTLY CLASSIFIED AS A 
MONSOON DEPRESSION, GENERALLY CHARACTERIZED AS A LARGE CYCLONIC 
CIRCULATION, GREATER THAN 600 NM DIAMETER, WITH ENHANCED WINDS OVER 
THE SOUTHERN PERIPHERY AND A WEAK CORE OF LIGHT WINDS. ANIMATED 
MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A BROAD CIRCULATION 
PARTIALLY OBSCURED BY CONVECTION BUILDING IN THE SOUTHEASTERN 
PERIPHERY OF THE CIRCULATION. ENVIRONMENTAL ANALYSIS REVEALS MOSTLY 
CONDUCIVE CONDITIONS FOR DEVELOPMENT WITH LOW TO MODERATE (15 TO 20 
KTS) VERTICAL WIND SHEAR, WARM SEA SURFACE TEMPERATURES (28 TO 29 C), 
AND GOOD UPPER-LEVEL OUTFLOW. GLOBAL MODELS INDICATE THAT THE BROAD 
CIRCULATION WILL STRUGGLE TO CONSOLIDATE INTO A TROPICAL CYCLONE AND 
ENSEMBLE MODELS DO NOT DEVELOP IT INTO TROPICAL CYCLONE STRENGTH IN 
THE NEXT 24-36 HOURS. FOR HAZARDS AND WARNINGS, REFERENCE THE FLEET 
WEATHER CENTER SAN DIEGO HIGH WINDS AND SEAS PRODUCT OR REFER TO LOCAL 
WMO DESIGNATED FORECAST AUTHORITY. MAXIMUM SUSTAINED SURFACE WINDS ARE 
ESTIMATED AT 27 TO 32 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED 
TO BE NEAR 1000 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT 
TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.
      (2) THE AREA OF CONVECTION (INVEST 97W) PREVIOUSLY LOCATED NEAR 
11.4N 135.9E IS NOW THE SUBJECT OF A TROPICAL CYCLONE WARNING. SEE 
PARA. 1.A.(3) FOR FURTHER DETAILS.
      (3) NO OTHER SUSPECT AREAS.
   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.
3. JUSTIFICATION FOR REISSUE:  UPGRADED AREA IN PARA 1.B.(2) TO 
WARNING STATUS.//

Prognostic Reasoning for Active Systems

Typhoon Saudel — 130 mph (1-minute sustained)

Issued: 2026-08-22 21:00:00 UTC

WDPN31 PGTW 222100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 17W (SAUDEL) WARNING NR 018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.4N 143.6E
   INITIAL INTENSITY: 115 KTS
   GEOGRAPHIC REFERENCE: 943 NM EAST-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 45 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
RAPIDLY DETERIORATING AND SHRINKING EYE FEATURE, WITH DEEP
CONVECTION CONFINED TO THE SOUTHWESTERN QUADRANT AND WARMING
CLOUD-TOPS ALONG THE NORTHEASTERN FLANK. THE SYSTEM HAS UNDERGONE A
REMARKABLE TRANSFORMATION IN JUST THE PAST TWO HOURS, FROM HAVING A
WELL-DEFINED, IF A BIT RAGGED, EYE FEATURE, TO NOW BARELY HOLDING
ONTO AN EXTREMELY SMALL AND ILL-DEFINED EYE, WITH WANING
CONVECTION. A 221550Z AMSR2 89GHZ MICROWAVE IMAGE PROVIDES SOME
INSIGHT INTO THE MOST LIKELY CAUSE, NAMELY THE ONSET OF AN ERC. THE
AMSR2 IMAGE DEPICTS A WELL-DEFINED INNER EYEWALL, CONSISTENT WITH
THE EIR IMAGERY AT THAT TIME, AND A STRONG SECONDARY EYEWALL
EVIDENT ABOUT 60NM OUTWARD FROM THE INNER. A MOAT IS ALSO EVIDENT
WRAPPING UP THE EASTERN FLANK OF THE CORE, ALL OF WHICH IS
CONSISTENT WITH AN ERC. THE CIMSS M-PERC ERC ONSET PROBABILITY
JUMPED UP TO 45 PERCENT BASED ON THIS RECENT DATA. A 221850Z SSMIS
91GHZ IMAGE DEPICTS THE SAME OVERALL SCENARIO, WITH AN EVEN BETTER
DEFINED MOAT, AND SECONDARY EYEWALL AND A MORE DEGRADED INNER
EYEWALL. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE
BASED ON THE ERODING EYE IN THE EIR. THE INITIAL INTENSITY IS
ASSESSED WITH HIGH CONFIDENCE, BASED ON THE OVERALL AGREEMENT OF
NEARLY ALL SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES NOTED
BELOW. ENVIRONMENTAL CONDITIONS ARE FAVORABLE OVERALL, WITH WARM
SSTS, HIGH (100 KJ PER CM2 OR GREATER) OHC, LOW DEEP-LAYER EASTERLY
SHEAR AND STRONG RADIAL OUTFLOW. HOWEVER, MODERATE MID-LEVEL SHEAR
AND THE ERC WILL SERVE TO OFFSET THE OVERALL FAVORABLE CONDITIONS
IN THE NEAR-TERM.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHWESTERN FLANK OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T6.0 - 115 KTS
   KNES: T6.0 - 115 KTS
   CIMSS SATCON: 114 KTS AT 221800Z
   CIMSS ADT: 112 KTS AT 221800Z
   CIMSS AIDT: 101 KTS AT 221800Z
   CIMSS D-MINT: 118 KTS AT 221610Z
   CIMSS D-PRINT: 116 KTS AT 221800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL
   OTHER FACTORS: NORTHWESTWARD OUTFLOW CHANNEL; MODERATE MID-LEVEL
SHEAR; EYEWALL REPLACEMENT CYCLE (ERC). 

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TYPHOON (TY) 17W (SAUDEL) IS TRACKING
NORTHWESTWARD ALONG THE SOUTHWESTERN FLANK OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHEAST, CONNECTING WITH
A SECOND STR CENTERED OVER SOUTHERN JAPAN. NO SIGNIFICANT CHANGE IN
THE TRACK IS EXPECTED FOR THE FIRST 60 HOURS OF THE FORECAST.
BEGINNING AT TAU 60 HOWEVER, THE GLOBAL MODELS BEGIN TO DIVERGE ON
HOW THEY HANDLE THE RIDGING PATTERN, SPECIFICALLY IN REGARDS TO THE
PASSAGE OF A TROUGH TO THE NORTH WILL IMPACT THE RIDGE. THE GFS
DEPICTS A MUCH STRONGER AND DEEPER TROUGH WHICH BREAKS DOWN THE
RIDGE FROM TAU 72 TO TAU 84, WHICH RESULTS IN A RAPID SLOWDOWN OF
TY 17W AS IT CROSSES THE RYUKYUS BEFORE TURNING WEST THEN SOUTHWEST
AS A RIDGE OVER CHINA BECOMES THE DOMINANT STEERING INFLUENCE AFTER
TAU 96. THE ECMWF ON THE OTHER HAND DEPICTS A MUCH WEAKER, NEARLY
NON-EXISTENT, TROUGH WHICH DOES NOT BREAK THE RIDGE, RESULTING IN A
FASTER TRACK WHICH EVENTUALLY CURVES SOUTHWESTWARD BY THE END OF
THE FORECAST PERIOD. THE EXPERIMENTAL AI MODELS ARE TRENDING MORE
TOWARDS THE GFS SCENARIO. TY 17W WILL SLOW DOWN AFTER TAU 60 AS IT
PASSES SOUTH OF THE WEAKNESS IN THE STEERING RIDGE, BEFORE PASSING
THROUGH THE RYUKYU CHAIN IN THE VICINITY OF OKINAWA SHORTLY AFTER
TAU 72. THE SYSTEM COMES UNDER THE INFLUENCE OF THE RIDGE OVER
NORTHERN CHINA BY TAU 96, AND BEGINS A TURN WEST-SOUTHWESTWARD TO
THE NORTHEAST OF TAIWAN. REGARDING INTENSITY, THE LIKELY ONSET OF AN
ERC WILL RESULT IN A SMALL AMOUNT OF WEAKENING OR MAINTENANCE OF
THE CURRENT INTENSITY THROUGH TAU 12. ONCE THE ERC IS COMPLETE, THE
SYSTEM WILL RESUME INTENSIFICATION AS IT PASSES OVER A POOL OF HIGH
OHC WATERS, WHILE MAINTAINING STRONG POLEWARD OUTFLOW ALOFT. BY TAU
36, THE SYSTEM IS EXPECTED TO BECOME MORE ISOLATED IN TERMS OF THE
UPPER-LEVEL PATTERN, WITH A RESULTANT REDUCTION IN OUTFLOW ALOFT.
BY TAU 48, UPPER-LEVEL NORTHERLY FLOW ALONG THE WESTERN FLANK OF
THE SYSTEM WILL RESULT IN A DRAMATIC INCREASE IN SHEAR, ACCELERATING
THE WEAKENING TREND BEGUN 12 HOURS EARLIER. THE SYSTEM IS FORECAST
TO STEADILY WEAKEN FROM THIS POINT ONWARDS, THOUGH IT WILL REMAIN A
STRONG TYPHOON AS IT PASSES OKINAWA. ONCE THE SYSTEM MOVES INTO THE
EAST CHINA SEA, CONDITIONS IMPROVE SLIGHTLY, ALLOWING TY 17W TO
MAINTAIN INTENSITY THROUGH TAU 120. 

MODEL DISCUSSION: TRACK GUIDANCE, WITH THE EXCEPTION OF NAVGEM, IS
IN GOOD OVERALL AGREEMENT THROUGH TAU 72, WITH A CROSS-TRACK SPREAD
OF 155NM BETWEEN JGSM ON THE SOUTHERN EDGE AND THE CLUSTER OF GFS,
GEFS AND THE AI MODELS ON THE NORTHERN EDGE. THE JTWC FORECAST IS
POSITIONED CLOSE TO THE CONSENSUS MEAN (MODIFIED TO DISREGARD
NAVGEM), AND THE ECMWF DETERMINISTIC TRACKER, JUST SOUTH OF THE
AI-GFS CLUSTER NOTED ABOVE, WITH HIGH CONFIDENCE. IN THE LONG-RANGE
FORECAST, THE MODELS BEGIN TO DIVERGE MORE SIGNIFICANTLY, PRIMARILY
IN THE ALONG-TRACK DIRECTION. ECMWF IS BY FAR THE FASTEST OF ALL
THE MODEL GUIDANCE, SHOWING LANDFALL IN SOUTHEASTERN CHINA BY TAU
120. THE AI-GFS CLUSTER ARE THE SLOWEST, REMAINING EAST OF 124E
LONGITUDE BY TAU 120. THE JTWC FORECAST IS POSITIONED CLOSE TO THE
MODIFIED CONSENSUS WITH MEDIUM CONFIDENCE. INTENSITY GUIDANCE IS IN
GOOD AGREEMENT, THE ONLY OUTLIER IS THE HAFS-A DEPICTING STEADY
WEAKENING AFTER TAU 12 TO TAU 96 BEFORE FLATTENING OUT. THE
REMAINDER OF THE GUIDANCE IS TIGHTLY CLUSTERED ABOUT THE MEAN, AND
THE JTWC FORECAST. OF NOTE, THE RIDE, RI25 AND RI30 RAPID
INTENSIFICATION (RI) AIDS ARE TRIGGERED WITH THIS RUN, THOUGH WITH
THE ONSET OF THE ERC, APPEAR UNLIKELY AT THIS TIME. 

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

Tropical Depression Narra — 35 mph (1-minute sustained)

Issued: 2026-08-22 21:00:00 UTC

WDPN32 PGTW 222100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 18W (NARRA) WARNING 
NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.0N 108.3E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 134 NM EAST OF HANOI, VIETNAM
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 10 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
DEPRESSION (TD) 18W (NARRA) WITH PERSISTENT CIRRUS CLOUD COVER OVER
THE ENTIRETY OF THE SYSTEM AND A LARGE AREA OF FLARING CONVECTION
CENTERED TO THE NORTHWEST OF THE LOW LEVEL CIRCULATION (LLC), OVER
THE COAST OF SOUTHERN CHINA AND NORTHEASTERN VIETNAM. RADAR IMAGERY
INDICATES THE CIRCULATION IS BROAD AND ELONGATED, WITH THE
STRONGEST BAND OF CONVECTION BEING POSITIONED OVER LAND IN VIETNAM
AND WRAPPING AROUND THE WESTERN FLANK OF 18W. CURRENT ENVIRONMENTAL
CONDITIONS ARE ASSESSED AS MARGINAL, AS THE VERY WARM (30-31 C) SEA
SURFACE TEMPERATURES (SSTS) ARE OFFSET BY MODERATE (20 KTS)
VERTICAL WIND SHEAR, WEAK POLEWARD OUTFLOW ALOFT, AND AN AREA OF
DRIER AIR TO THE SOUTH OF THE SYSTEM. THE INITIAL POSITION IS
PLACED WITH LOW CONFIDENCE BASED ON A COMBINATION OF RADAR IMAGERY
AND AGENCY FIXES. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON AGENCY DVORAK FIXES, CIMSS OBJECTIVE ESTIMATES,
AND A SURFACE OBSERVATION FROM BACH LONG VY TO THE SOUTH OF 21 KTS
WESTERLY AT 221800Z.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: WEAK STEERING ENVIRONMENT COMPRISED OF
A NEAR-EQUATORIAL RIDGE (NER) CENTERED TO THE SOUTHWEST AND A
SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.0 - 30 KTS
   KNES: T2.5 - 35 KTS
   CIMSS D-MINT: 37 KTS AT 221752Z
   CIMSS D-PRINT: 36 KTS AT 221810Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: WEAK EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TD 18W IS FORECAST TO CONTINUE MEANDERING,
GENERALLY COUNTERCLOCKWISE LOOP WITHIN THE GULF OF TONKIN FOR THE
REMAINDER OF THE FORECAST PERIOD BEFORE MAKING LANDFALL AND
DISSIPATING IN THE VICINITY OF BEIHAI BY TAU 96. AN ERRATIC TRACK
IN THE SHORT-TERM IS EXPECTED AS 18W REMAINS IN A WEAK STEERING
ENVIRONMENT BETWEEN THE INFLUENCE OF A NEAR-EQUATORIAL RIDGE (NER)
CENTERED TO THE SOUTHWEST AND A SUBTROPICAL RIDGE (STR) CENTERED TO
THE NORTH OF 18W. CURRENTLY, THE NER IS ASSESSED AS BEING A MORE
DOMINANT FACTOR, CAUSING THE INITIAL SOUTHWARD MOVEMENT IN TRACK
UNTIL TAU 48, AT WHICH POINT THE NER RETREATS TO THE SOUTHWEST AND
THE STR CENTERED TO THE NORTH BUILDS AND CONNECTS WITH ANOTHER STR
CENTERED OVER KYUSHU, CAUSING A POLEWARD TURN BY TAU 60 AND
LANDFALL TO THE EAST OF THE LEIZHOU PENINSULA. REGARDING INTENSITY,
TD 18W IS EXPECTED TO HAVE A SHORT WINDOW FOR INTENSIFICATION IN
THE SHORT TERM AS THE VWS MOMENTARILY ABATES AND OUTFLOW ALOFT
IMPROVES. THIS IS EXPECTED TO BE SHORT-LIVED, AND BY TAU 48 VWS
WILL SHARPLY INCREASE TO OVER 25 KTS, INTRODUCING MID-LEVEL DRIER
AIR, BEGINNING DISSIPATION OF TD 18W OVER WATER BY TAU 72 BEFORE IT
MAKES LANDFALL AND DISSIPATES BY TAU 96.

MODEL DISCUSSION: TRACK MODEL GUIDANCE IS IN POOR OVERALL AGREEMENT
AS THERE CONTINUES TO BE A WIDE SPREAD OF EXPECTED DIRECTIONS AND
TRACK SPEED, ALTHOUGH THERE REMAINS AGREEMENT ON THE GENERAL
SOUTHWARD MOTION OF TD 18W OUT TO TAU 48. GFS IS THE WESTERNMOST
SOLUTION AND MAINTAINS 18W OVER WATER FOR THE ENTIRETY OF THE
FORECAST PERIOD. CONVERSELY, GALWEM AND THE EXPERIMENTAL GOOGLE
DEEPMIND TAKE 18W THE FARTHEST EAST, DEPICTING POSSIBLE LANDFALL
OVER NORTHERN HAINAN AND THE SOUTHERN TIP OF THE LEIZHOU PENINSULA
BEFORE CONTINUING OUT INTO THE SOUTH CHINA SEA. THE OFFICIAL JTWC
FORECAST TRACK IS PLACED WITH LOW CONFIDENCE, CLOSELY IN LINE WITH
THE MULTI-MODEL CONSENSUS EXCLUDING NAVGEM, ALSO CLOSELY IN LINE
WITH THE TRACK OF THE AI CONSENSUS, WHICH BOTH FALL WITHIN THE
CENTER OF THE GUIDANCE PACKAGE. REGARDING INTENSITY, THE GFS AND
ECMWF GLOBAL MODELS DEPICT DIFFERENT ENVIRONMENTAL OUTLOOKS IN THE
SHORT-TERM, LENDING SOME UNCERTAINTY TO THE INTENSITY FORECAST.
ECMWF PREDICTS MORE FAVORABLE VWS FROM TAUS 12 TO 36, ALLOWING FOR
TD 18W TO INTENSIFY, WHILE GFS IS MORE CONSERVATIVE, MAINTAINING
VWS ABOVE 15 KTS DURING THIS PERIOD AND THUS LESS CHANCE FOR
INTENSIFICATION. THE OFFICIAL JTWC INTENSITY FORECAST IS ASSESSED
WITH LOW CONFIDENCE, CLOSELY IN LINE WITH THE DETERMINISTIC GFS
SOLUTION.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: LOW
   TRACK 72-120 HR: LOW
   INTENSITY 00-72 HR: LOW
   INTENSITY 72-120 HR: LOW//

Tropical Depression Nineteen — 35 mph (1-minute sustained)

Issued: 2026-08-22 21:00:00 UTC

WDPN33 PGTW 222100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 19W (NINETEEN) 
WARNING NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.5N 135.5E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 233 NM NORTHWEST OF YAP
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A LOOSELY
ORGANIZED AND ASYMMETRIC SYSTEM, WITH DEEP CONVECTION ALONG THE
WESTERN FLANK. THE LOW LEVEL CIRCULATION CENTER (LLCC) IS OBSCURED,
BUT AN EARLIER 221201Z ASCAT-B PASS REVEALED A COMPACT LLCC WITH
20-25 KNOT WINDS, POSITIONED EAST OF THE CONVECTIVE ENVELOPE. LATE
RECEIPT OF A 221625Z AMSR3 37GHZ MICROWAVE IMAGE SUGGESTS THE LLCC
IS POSITIONED A BIT FURTHER NORTHWEST THAN THE 1800Z POSITION,
WHICH WILL BE REPOSITIONED PRIOR TO THE NEXT FORECAST. THE AMSR3
IMAGE ALSO REVEALS THE ASYMMETRIC NATURE OF THE SYSTEM, WITH DEEP
CONVECTION CONFINED TO THE WESTERN PORTION OF THE CIRCULATION,
WHILE DRY AIR AND EASTERLY SHEAR LIMIT CONVECTIVE DEVELOPMENT ON
THE EASTERN PERIMETER. THE INITIAL POSITION IS ASSESSED WITH LOW
CONFIDENCE USING AN EXTRAPOLATION OF THE EARLIER ASCAT DATA AND
ANIMATED SHORTWAVE INFRARED (SWIR) IMAGERY. THE INITIAL INTENSITY
IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE AGREEMENT OF THE BULK
OF SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES NOTED BELOW AND
EXTRAPOLATION OF THE EARLIER ASCAT DATA.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: NORTHERN PERIPHERY OF A LOW- TO
MID-LEVEL NEAR EQUATORIAL RIDGE (NER) TO THE SOUTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T2.5 - 35 KTS
   CIMSS SATCON: 31 KTS AT 221910Z
   CIMSS ADT: 31 KTS AT 221800Z
   CIMSS AIDT: 30 KTS AT 221800Z
   CIMSS D-MINT: 34 KTS AT 221708Z
   CIMSS D-PRINT: 29 KTS AT 221800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: WEAK EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL DEPRESSION (TD) 19W IS POSITIONED IN
THE FAR SOUTHWESTERN END OF A AN AREA OF TROUGHING EXTENDING
SOUTHWESTWARD FROM TY 17W (SAUDEL), AND ALONG THE NORTHERN EDGE OF
A BROAD REGION OF MONSOON CROSS-EQUATORIAL SOUTHERLY FLOW, WHICH IS
PUSHING THE SYSTEM SLOWLY NORTHWARD AT THE CURRENT TIME. OVER THE
NEXT 12 HOURS, THE LOW- TO MID-LEVEL NEAR EQUATORIAL RIDGE (NER) TO
THE SOUTHEAST WILL BUILD, RESULTING IN TD 19W BEGINNING A SLOW TURN
NORTHEASTWARD. BY TAU 24, TY 17W WILL BE POSITIONED DUE NORTH OF TD
19W, AND BEGIN TO EXERT A POLEWARD PULL ON TD 19W. SIMULTANEOUSLY,
THE NER TO THE SOUTHEAST CONTINUES TO BUILD, STRENGTHENING THE
STEERING GRADIENT, DRIVING TD 19W EVEN FASTER NORTHWARD. THE SYSTEM
SLOWS AND CURVES NORTHWESTWARD BY THE END OF THE FORECAST, AS THE
PRIMARY STEERING INFLUENCE IS HANDED OFF FROM THE NER TO THE
SOUTHEAST TO A STR TO THE NORTHEAST. REGARDING INTENSITY, THE
SYSTEM HAS A BRIEF WINDOW OF OPPORTUNITY, WITH RELATIVELY LIGHTER
SHEAR EXPECTED, WHEREIN TO INTENSIFY UP TO MINIMAL TROPICAL STORM
(TS) STRENGTH. HOWEVER, BY TAU 24 SHEAR IS FORECAST TO INCREASE
SHARPLY AND STAY ELEVATED THROUGH THE REMAINDER OF THE FORECAST
PERIOD, LEADING TO DISSIPATION BY TAU 60. 

MODEL DISCUSSION: TRACK GUIDANCE, WITH THE EXCEPTION OF NAVGEM, IS
IN GOOD AGREEMENT, WITH LESS THAN 120NM OF CROSS-TRACK SPREAD,
THROUGH THE FORECAST PERIOD. THE JTWC FORECAST IS PLACED NEAR THE
ECMWF TRACKER WITH HIGH CONFIDENCE. INTENSITY GUIDANCE IS IN GOOD
AGREEMENT AS WELL, WITH THE BULK OF MODELS INDICATING A BRIEF
PERIOD OF INTENSIFICATION UP TO 35 KNOTS BY TAU 12, FOLLOWED BY A
SLOW BUT STEADY WEAKENING TREND THROUGH THE END OF THE FORECAST
PERIOD. THE ONLY EXCEPTION IS COAMPS-TC WHICH DEPICTS RAPID
INTENSIFICATION THROUGH TAU 36, UP TO 55 KNOTS, FOLLOWED BY RAPID
WEAKENING THEREAFTER. THE JTWC FORECAST IS PLACED NEAR THE
CONSENSUS MEAN, WITH MEDIUM CONFIDENCE. 

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