WDXS31 PGTW 022100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 29S (INDUSA) WARNING NR 
004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.6S 73.5E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 335 NM SOUTH OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE (TC) 29S (INDUSA) RECOVERING FROM THE SLIGHT DRY AIR
ENTRAINMENT THAT HAD PREVIOUSLY STAGNATED ITS DEVELOPMENT. WHILE
DRIER AIR IS STILL PRESENT ALONG THE WESTERN FLANK, INDUSA APPEARS
TO BE FIGHTING BACK. DEEP CONVECTION HAS REFORMED ALONG THE
NORTHERN AND EASTERN FLANKS AND HAS STARTED TO WRAP INTO THE
EXPANDING CENTRAL DENSE OVERCAST. ENVIRONMENTAL ANALYSIS REVEALS A
HIGHLY FAVORABLE ENVIRONMENT DESPITE THE DRIER AIR TO THE WEST,
CHARACTERIZED BY LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS), HIGH
(29-30 C) SEA SURFACE TEMPERATURES (SST), AND ROBUST POLEWARD
OUTFLOW. A 021321Z RCM-2 SAR PASS AND A 021621Z METOP-C
SCATTEROMETER IMAGE REVEALED THE HIGHEST WINDS ARE CONFINED TO THE
NORTHEASTERN QUADRANT AND SUPPORT THE INITIAL INTENSITY WITH HIGH
CONFIDENCE. THE INITIAL POSITION IS ALSO PLACED WITH HIGH
CONFIDENCE BASED ON THE AFOREMENTIONED SAR AND SCATTEROMETER
IMAGES.

INITIAL WIND RADII BASIS: 021321Z RCM-2 SAR DATA SUPPORTED BY
021621Z METOP-C SCATTEROMETER DATA

CURRENT STEERING MECHANISM: A DEEP-LAYER SUBTROPICAL RIDGE (STR)
CENTERED TO THE SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   FMEE: T3.5 - 55 KTS
   FIMP: T3.0 - 45 KTS
   CIMSS SATCON: 54 KTS AT 011830Z
   CIMSS ADT: 55 KTS AT 021830Z
   CIMSS AIDT: 43 KTS AT 021830Z
   CIMSS D-PRINT: 39 KTS AT 021700Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 29S IS FORECAST TO CONTINUE ITS
SOUTH-SOUTHWESTWARD TRACK FOR THE NEXT 36 HOURS WHILE IT REMAINS ON
THE NORTHWESTERN PERIPHERY OF THE STEERING RIDGE. AROUND TAU 48,
29S WILL APPROACH THE RIDGE AXIS AND RECURVE, INDUCING A
SOUTH-SOUTHEAST TRAJECTORY FOR THE REMAINDER OF THE FORECAST
PERIOD. REGARDING INTENSITY, INDUSA WILL CONTINUE TO INTENSIFY
UNTIL TAU 48, PEAKING AROUND THE SAME TIME IT ROUNDS THE RIDGE AXIS
AT AN INTENSITY OF 90 KTS. AFTER ROUNDING THE RIDGE AXIS, 29S WILL
ENTER INTO AN INCREASINGLY HOSTILE ENVIRONMENT, ENCOUNTERING
UNFAVORABLE VWS INDUCED BY JET INTERACTION AND DECREASING SSTS IN
AN OVERALL DRY ENVIRONMENT. 29S IS FORECAST TO BEGIN EXTRATROPICAL
TRANSITION (ETT) AROUND TAU 72 AND IS EXPECTED TO BE FULLY
EXTRATROPICAL BY TAU 96.

MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN STRONG
AGREEMENT FOR THE DURATION OF THE FORECAST PERIOD. THE ONLY
OUTLIERS ARE GALWEM AND NAVGEM, WHICH DIVERGE FROM THE TIGHT
ENVELOPE SLIGHTLY BETWEEN TAU 72-96. DISCOUNTING GALWEM AND NAVGEM,
THE CROSS-TRACK SPREAD IS 60NM AT TAU 96 AND THE ALONG-TRACK SPREAD
IS 30NM AT TAU 96, LENDING HIGH CONFIDENCE TO THE JTWC TRACK
FORECAST. RELIABLE INTENSITY AIDS ARE IN AGREEMENT IN SUSTAINED
INTENSIFICATION THROUGH TAU 48, AND STEADY WEAKENING FOR THE
REMAINDER OF THE FORECAST PERIOD. MODELS DISAGREE ON THE PEAK
INTENSITY, THOUGH ALL MODELS INDICATE A PEAK OCCURRING AT TAU 48.
TWO JTWC RI AIDS SUGGEST THE POSSIBILITY OF RI THROUGH TAU 48,
THOUGH MESOSCALE AND GLOBAL MODELS ARE MORE CONSERVATIVE. THE JTWC
INTENSITY FORECAST ANTICIPATES NEAR RI THROUGH TAU 48, IN CLOSE
ALIGNMENT WITH THE MULTI-MODEL CONSENSUS. AS A RESULT, THE JTWC
INTENSITY FORECAST IS PLACED WITH OVERALL MEDIUM CONFIDENCE.

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