WDXS32 PGTW 182100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 10S (TEN) WARNING NR 
004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.2S 117.3E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 258 NM NORTHEAST OF LEARMONTH, AUSTRALIA
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A
CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) OBSCURED BY
RECENTLY FLARING CONVECTION TO THE WEST AND DIRECTLY OVER THE LLCC. 
THE SYSTEM IS SHOWING SIGNS OF DEVELOPMENT, AS MORE FEEDER BANDS WRAP 
INTO THE CENTER AND OVERALL TURNING BECOMES MORE PRONOUNCED. THE 
OUTFLOW REMAINS RADIAL, WITH MORE PROMINENT POLEWARD AND EQUATORWARD 
CHANNELS, AS DEPICTED IN THE ANIMATED MSI. THE INITIAL POSITION IS 
PLACED WITH HIGH CONFIDENCE BASED ON RECENTLY PARTIALLY EXPOSED LLCC, 
CONSISTENT WITH A 181430Z ASCAT-C POSITION EXTRAPOLATION. THE INITIAL 
INTENSITY OF 45 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE 
181418Z METOP-C UHR ASCAT IMAGE SHOWING A BROAD SWATH OF 35-40 KNOT 
WINDS. ADDITIONALLY, AGENCY DVORAK ESTIMATES OF T2.5-3.0 AND CIMSS 
OBJECTIVE ESTIMATES RANGING FROM 36-45 KTS FURTHER SUPPORTED THE 
INITIAL INTENSITY ASSESSMENT.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   DEMS: T3.0 - 45 KTS
   APRF: T2.5 - 35 KTS
   CIMSS SATCON: 40 KTS AT 181800Z
   CIMSS ADT: 37 KTS AT 181800Z
   CIMSS AIDT: 36 KTS AT 181800Z
   CIMSS DPRINT: 45 KTS AT 181830Z
   CIMSS DMINT: 43 KTS 181723Z

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

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: FOLLOWING A SLIGHTLY ERRATIC MOTION OVER THE
LAST 12 HOURS DRIVEN BY A WEAK, BUT SLOWLY DEVELOPING STEERING
PATTERN, TC 10S IS FORECAST TO NOW CONTINUE TRACKING SOUTHWESTWARD
WITH A CLOSEST POINT OF APPROACH TO LEARMONTH, AUSTRALIA OF
APPROXIMATELY 90 NM. AS THE SUBTROPICAL RIDGE (STR) TO THE
SOUTHEAST BUILDS, TC 10S WILL CONTINUE TO TRAVEL ALONG ITS WESTERN
PERIPHERY. STRONGLY FAVORABLE ENVIRONMENTAL CONDITIONS WILL LEAD TO
RAPID INTENSIFICATION (RI) OVER THE NEXT 36 HOURS. NEAR TAU 48,
THE SYSTEM IS EXPECTED TO BEGIN RAPIDLY WEAKENING, DUE TO SEA SURFACE 
TEMPERATURES DROPPING TO AROUND 24 C, INCREASING VERTICAL
WIND SHEAR AND INTRUDING DRY AIR. TC 10S IS FORECAST TO WEAKEN DOWN TO 
35 KTS AT THE END OF THE FORECAST PERIOD, WITH DISSIPATION SOON 
THEREAFTER. 

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT IN
REGARD TO THE MOVEMENT TRACK, WITH ALL TRACKERS IN CLOSE PROXIMITY
TO THE MULTI-MODEL CONSENSUS, LEADING TO HIGH CONFIDENCE IN THE
JTWC TRACK THROUGHOUT THE FIRST 72 HOURS, AS INDICATED BY THE
CROSS-TRACK SPREAD OF 90 NM. THE TRACK AIDS DIFFUSE AFTERWARDS,
HOWEVER, ALL ARE FORECASTING MOTION ALONG THE WESTERN PERIPHERY
OF THE STR TO THE EAST. INTENSITY FORECAST CONFIDENCE IS ASSESSED
AS MEDIUM DUE TO RATHER LARGE SPREAD BETWEEN THE RI AND OTHER
DETERMINISTIC MODEL AIDS DIFFERING SIGNIFICANTLY IN THE RATE OF
INTENSIFICATION, AS WELL AS PEAK INTENSITY. HAFS-A IS A SIGNIFICANT 
OUTLIER THIS RUN, WITH A PEAK INTENSITY OF JUST 50 KTS AT TAU 60, MUCH 
WEAKER THAN THE REMAINDER OF GUIDANCE. GIVEN THE STRONGLY FAVORABLE 
ENVIRONMENTAL CONDITIONS, THE JTWC INTENSITY FORECAST REMAINS ON THE 
HIGHER END OF THE SPECTRUM AND IS CONSISTENT WITH THE PEAK INTENSITY 
OF 90 KTS, AS FORECAST BY MULTIPLE RI AIDS.

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