TC 29S (INDUSA) peaks at CAT 2 US//TC 30P very slow moving and intensifying/INVEST 91P medium

WDXS31 PGTW 040900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 29S (INDUSA) WARNING 
NR 007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.3S 70.2E
   INITIAL INTENSITY: 90 KTS
   GEOGRAPHIC REFERENCE: 726 NM EAST OF PORT LOUIS, MAURITIUS
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 36 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A SMALL,CLOUD-COVERED EYE FEATURE, WHILE ENHANCED INFRARED (EIR) IMAGERY REVEALS A DISTINCT PINHOLE EYE DIAMETER MEASURED AT APPROXIMATELY 10NM. BOTH MSI AND EIR, AUGMENTED BY A 040448Z AMSU-B 89GHZ MICROWAVE PASS, INDICATE A HIGHLY COMPACT INNER CORE AND MINIATURE CENTRAL DENSE OVERCAST (CDO), WITH CONVECTIVE FEEDER BANDS EXTENDING PERIPHERALLY, PARTICULARLY IN THE NORTHERN QUADRANT. ANIMATED WATER VAPOR IMAGERY AND CIMSS ATMOSPHERIC MOTION VECTORS (AMVS) INDICATE EXTREMELY VIGOROUS POLEWARD OUTFLOW CHANNELS SOUTHWARD IN ADVANCE OF 
A DEEP UPPER-LEVEL TROUGH APPROACHING FROM THE WEST. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE EYE FEATURE IN 
THE GOES-IO EIR IMAGERY. THE INITIAL INTENSITY IS ASSESSED WITH LOW CONFIDENCE HOWEVER. AGENCY SUBJECTIVE DVORAK FIXES ARE CONSISTENT AT 
T4.5, HOWEVER THE OBJECTIVE TECHNIQUES (PRIMARILY ADT AND AIDT) ARE STRUGGLING TO RESOLVE THE PINHOLE EYE AND PROVIDING ESTIMATES FAR TOO LOW. THE INITIAL INTENSITY OF 90 KNOTS IS DERIVED FROM EXTRAPOLATION FROM EARLIER SAR PEAK VMAX DATA, A 0047Z D-MINT ESTIMATE OF 88 KNOTS AND AN OVERALL QUALITATIVE ASSESSMENT OF THE STRUCTURE OF THE SYSTEM IN THE EIR, PARTICULARLY THE BD-ENHANCEMENT. ENVIRONMENTAL CONDITIONSARE FAVORABLE, WITH LOW VERTICAL WIND SHEAR (VWS), WARM SSTS AND
ROBUST POLEWARD OUTFLOW.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED TO THE EAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   DEMS: T4.5 - 77 KTS
   FMEE: T4.5 - 77 KTS
   FIMP: T4.5 - 77 KTS
   CIMSS ADT: 51 KTS AT 040600Z
   CIMSS AIDT: 56 KTS AT 040600Z
   CIMSS D-MINT: 88 KTS AT 040047Z
   CIMSS D-PRINT: 70 KTS AT 040530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE FORECAST HAS BEEN TRUNCATED TO 36HOURS WITH EXTRATROPICAL TRANSITION. 

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 29S (INDUSA) HAS TRACKED SOUTHWESTWARD OVER THE PAST 12 HOURS ALONG THE NORTHWESTERN FLANK
OF THE STR TO THE EAST. IT IS CURRENTLY APPROACHING THE RIDGE AXIS,AND GRADUALLY TURNING SOUTHWARD WHILE SLOWING DOWN AS IT NEARS THE WEAKEST STEERING GRADIENT AT THE RIDGE AXIS. THE SYSTEM IS FORECAST TO CROSS THE RIDGE AXIS AND ACCELERATE SOUTHWARD AFTER TAU 12, THEN RECURVE SOUTHEASTWARD WHILE ACCELERATING THROUGH THE REMAINDER OF THE 
PERIOD AS IT INTERACTS WITH A TIGHTENING STEERING GRADIENT BETWEEN THE STR AND A DEEP MID-LATITUDE TROUGH. REGARDING INTENSITY, THE 
SYSTEM RAPIDLY INTENSIFIED OVER THE PAST 12 HOURS, INCREASING FROM 65-90 KNOTS UNDER HIGHLY FAVORABLE ENVIRONMENTAL CONDITIONS, BUT TC 29S HAS LIKELY REACHED ITS PEAK INTENSITY AT 0600Z. NORTHWESTERLY SHEAR IS STEADILY INCREASING, BRINGING DRY MID-LEVEL AIR IN WITH IT; 
HOWEVER, AS THE SYSTEM ACCELERATES AFTER TAU 12, VORTEX COHERENCE MAY BE SUSTAINED AS IT TEMPORARILY OUTPACES THE SHEAR. BY TAU 24, 
INCREASING SHEAR MAGNITUDE WILL MARK THE ONSET OF A RAPID CYCLOLYSIS PHASE. THE SYSTEM WILL BECOME SHEARED BY TAU 24, WITH DRY AIR 
ENTRAINMENT ENVELOPING THE REMNANT LOW-LEVEL VORTEX AS IT IS DISPLACED UNDER A STRONG JET STREAK. BY TAU 36, TC 29S WILL HAVE TRANSITIONED TO A WARM-CORE SECLUSION TYPE EXTRA-TROPICAL LOW AS IT RACES POLEWARD. 

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, WHICH DEPICTS A FAR TO WIDE OF A POLEWARD TURN, ALL OF THE AVAILABLE MODEL GUIDANCE IS IN VERY STRONG AGREEMENT, WITH THE CONSENSUS MEMBERS CONFINED TO A 50NM WIDE CROSS-TRACK ENVELOPE AT TAU 36. THE JTWC FORECAST IS CONSISTENT WITH THE MULTI-MODEL ENSEMBLE MEAN THROUGH THE FORECAST PERIOD WITH HIGH CONFIDENCE. INTENSITY GUIDANCE IS A BIT MORE MIXED, WITH THE HAFS-A DEPICTING A VERY SLOW AND GRADUAL WEAKENING OF TC 29S, KEEPING IT ABOVE 50 KNOTS EVEN AS LATE AS 120 HOURS OUT.THE COAMPS-TC AND HWRF ON THE OTHER HAND WEAKEN THE SYSTEM EXTREMELY RAPIDLY, DOWN TO 40 KNOTS BY TAU 36. THE DECAY-SHIPS TAKES A MORE REASONABLE MIDDLE GROUND, AND THE JTWC FORECAST IS PLACED NEAR THE SHIPS AND THE CONSENSUS MEAN WITH HIGH CONFIDENCE. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: HIGH//
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Platform: RCM-1
Acquisition Date: 2026-04-04 00:38:16 UTC
Storm Name: SH292026 / INDUSA
Storm ID: SH29
Storm Center Longitude: 70.444
Storm Center Latitude: -19.224
Incidence Angle (Degrees): 57.646
Quadrant 1 NE VMax (kts): 81.45
Quadrant 2 SE VMax (kts): 81.96
Quadrant 3 SW VMax (kts): 72.49
Quadrant 4 NW VMax (kts): 65.60
RMax (nmi): 6.00 - 10.00

 

WDPS31 PGTW 040300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 30P (THIRTY) WARNING NR 
001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 9.1S 155.1E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 717 NM NORTHEAST OF CAIRNS, AUSTRALIA
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL CYCLONE 30P WITH A PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) AND DEEP CONVECTION SLIGHTLY OFFSET TO THE WEST OF THE LLCC. A PARTIAL 032308Z METOP-B ASCAT PASS REVEALED A SWATH OF 35 KNOT WINDS CONFINED TO THE NORTHERN SEMICIRCLE OF THE SYSTEM. THE
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE PARTIALLY EXPOSED LLCC IN ANIMATED MSI. THE INITIAL INTENSITY OF 35
KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED ASCAT PASS AND AN EARLY DPRINT ESTIMATE OF 33 KTS AT 040100Z.
ENVIRONMENTAL ANALYSIS INDICATES THAT 30P IS CURRENTLY IN A FAVORABLE ENVIRONMENT CHARACTERIZED BY MODERATE POLEWARD AND
EQUATORWARD OUTFLOW ALOFT, LOW (10-15 KTS) EASTERLY VERTICAL WIND SHEAR, AND WARM (29-30 C) SEA SURFACE TEMPERATURES.

INITIAL WIND RADII BASIS: 032308Z METOP-B ASCAT SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: A COMPETING STEERING ENVIRONMENT WITH A SUBTROPICAL RIDGE (STR) CENTERED OVER CENTRAL AUSTRALIA AND A
NEAR-EQUATORIAL RIDGE (NER) POSITIONED TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   CIMSS D-PRINT: 33 KTS AT 040100Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TC 30P IS FORECAST TO REMAIN WITHIN A COMPETING STEERING ENVIRONMENT THROUGHOUT THE ENTIRE 120-HOUR
FORECAST, CAUSING IT TO BE QUASI-STATIONARY WITHIN THE SOLOMON SEA. THE RIDGING TO BOTH THE NORTH AND SOUTH OF THE SYSTEM IS EXPECTED
TO MAINTAIN CONTROL OVER THE SYSTEM THROUGHOUT THE FORECAST PERIOD, CREATING VERY SLOW TRACK SPEEDS. THE ACTUAL TRACK DIRECTION OF 30P WILL LIKELY BE HIGHLY ERRATIC DUE TO THE COMPETING STEERING. A FAVORABLE ENVIRONMENT WITH WARM SEA SURFACE TEMPERATURES AND LOW
SHEAR WILL ALLOW FOR INTENSIFICATION THROUGH TAU 72 BEFORE THE UPWELLING OF COOLER WATERS BEGINS TO TAKE A TOLL ON THE SYSTEM. AS A RESULT, 30P IS FORECAST TO WEAKEN FROM TAU 72 THROUGH TAU 120 AS IT REMAINS NEARLY STATIONARY WITHIN THE SOLOMON SEA. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN AGREEMENT ON A VERY SLOW WESTWARD MOVEMENT THROUGH TAU 36. AFTER TAU 36, MODELS BEGIN TO DIVERGE IN NEARLY ALL DIRECTIONS, CREATING A HIGH AMOUNT OF UNCERTAINTY. IN LARGE, MODELS KEEP THE SYSTEM EAST OF PAPUA NEW GUINEA THROUGHOUT THE ENTIRE FORECAST PERIOD, THOUGH AN EXACT
DIRECTION IS NEARLY IMPOSSIBLE TO PREDICT. INTENSITY GUIDANCE IS IN BETTER AGREEMENT, WITH ALL MODELS SHOWING INTENSIFICATION THROUGH
TAU 72. HAFS-A AND HWRF ARE THE MOST AGGRESSIVE MODELS, SUGGESTING A PEAK INTENSITY OF AROUND 110 KTS. THE JTWC INTENSITY FORECAST IS PLACED QUITE A BIT LOWER, WITH A PEAK OF 80 KTS, DUE TO THE EXPECTED UPWELLING EFFECTS ON THE SYSTEM. AFTER TAU 72, MODELS AGREE ON WEAKENING THROUGH TAU 120. THE JTWC INTENSITY FORECAST IS
ASSESSED WITH OVERALL MEDIUM CONFIDENCE DUE TO UNCERTAINTY REGARDING HOW MUCH OF AN EFFECT THE UPWELLING WILL HAVE ON THE
SYSTEM AND POTENTIAL FOR TRACK VARIATION. 

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