WDXS31 PGTW 140900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 29S (TWENTYNINE) 
WARNING NR 011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.9S 123.1E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 246 NM NORTH-NORTHEAST OF BROOME,
AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE 29S WITH A MORE COMPACT CORE OF CENTRAL CONVECTION AND A
LOW-LEVEL CIRCULATION CENTER (LLCC) THAT IS QUICKLY CONSOLIDATING
OVER THE PAST 4 HOURS OR SO. A 140551Z AMSR2 89 GHZ MICROWAVE IMAGE
REVEALED THE LOW-LEVEL CLOUDS BEGINNING TO TIGHTLY WRAP INTO THE
CENTER WITH DEEP CONVECTION DISPLACED ABOUT 35 NM TO THE EAST.
ENVIRONMENTAL ANALYSIS INDICATES THAT 29S IS IN A FAVORABLE
ENVIRONMENT CHARACTERIZED BY MODERATE POLEWARD AND EQUATORWARD
OUTFLOW, LOW (5-10 KTS) VERTICAL WIND SHEAR, AND WARM (29-30 C) SEA
SURFACE TEMPERATURES.  THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE MENTIONED AMSR2 MICROWAVE IMAGE. THE
INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON THE AGENCY DVORAK AND OBJECTIVE INTENSITY ESTIMATES LISTED
BELOW. ADDITIONALLY, A 140118Z METOP-B ASCAT IMAGE SHOWING A SWATH
OF 30 KTS WITHIN THE SOUTHERN SEMICIRCLE.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: NORTHERN PERIPHERY OF AN EXTENSION OF A
SUBTROPICAL RIDGE TO THE SOUTHWEST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   APRF: T2.0 - 30 KTS
   CIMSS SATCON: 42 KTS AT 140700Z
   CIMSS ADT: 47 KTS AT 140600Z
   CIMSS AIDT: 43 KTS AT 140600Z
   CIMSS DPRINT: 26 KTS AT 140600Z
   CIMSS DMINT: 29 KTS AT 140552Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD

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: TC 29S IS FORECAST TO TRACK GENERALLY WESTWARD
THROUGH TAU 48. NEAR TAU 48, A LONG WAVE TROUGH WILL BREAK DOWN THE
RIDGE AND CAUSE 29S TO COME TO A HALT AND BEGIN A SHARP
EAST-SOUTHEASTWARD TURN. 29S WILL CONTINUE TO TRACK IN THE
EAST-SOUTHEASTWARD DIRECTION THROUGH THE REMAINDER OF THE FORECAST
PERIOD. REGARDING INTENSITY, TC 29S IS FORECAST TO RAPIDLY
INTENSIFY OVER THE NEXT 48 HOURS TO A PEAK OF 105 KTS, DUE TO THE
EXPECTED HIGHLY FAVORABLE ENVIRONMENT. SHEAR IS FORECAST TO REMAIN
BELOW 10 KTS AND OUTFLOW WILL BECOME STRONG. NEAR TAU 48, WESTERLY
SHEAR IS EXPECTED TO BEGIN QUICKLY RISING WITH VALUES NEAR 20 KTS
AT TAU 72, 35 KTS AT TAU 96, AND 45 KTS AT TAU 120. THESE HIGH
SHEAR VALUES, ALONG WITH INCREASING DRY AIR ENTRAINMENT FROM THE
WEST, WILL CAUSE 29S TO RAPIDLY WEAKEN THROUGH TAU 120 AS THE
SYSTEM TRACKS BACK TOWARD THE COAST OF AUSTRALIA. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT THROUGH TAU 72 WITH A 160 NM CROSS-TRACK SPREAD AT TAU
72. AFTERWARD, MODEL BEGIN TO DIVERGE DUE TO VARYING RESPONSES TO
THE INTERACTION WITH THE LONG WAVE TROUGH. GFS REMAINS THE
WESTERNMOST MEMBER WHILE ECMWF HAS THE VORTEX MAKE A SHARPER
EASTWARD TURN. AS A RESULT, THE JTWC TRACK FORECAST IS PLACED WITH
HIGH CONFIDENCE THROUGH TAU 72 AND LOW CONFIDENCE THEREAFTER.
INTENSITY GUIDANCE IS IN BETTER AGREEMENT WITH NEARLY ALL CONSENSUS
MEMBERS NOW DEPICTING RAPID INTENSIFICATION OVER THE NEXT 24 HOURS.
COAMPS-TC RI AND DTOP ARE BOTH TRIGGERING THIS RUN. PEAK
INTENSITIES NOW RANGE FROM 80 KTS (GFS) TO 140 KTS (HAFS-A). THE
JTWC INTENSITY FORECAST IS PLACED IN THE MIDDLE OF THE PACK WITH A
PEAK OF 105 KTS. ALL MODELS AGREE ON RAPID WEAKENING AFTER TAU 60.
OVERALL, THE JTWC INTENSITY FORECAST IS PLACED WITH MEDIUM
CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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