WDXS33 PGTW 120900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 14S (TALIAH) WARNING 
NR 023//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.7S 90.6E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 492 NM SOUTHWEST OF THE COCOS ISLANDS
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 32 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE 14S (TALIAH) WITH A VERY LARGE, RAGGED EYE AND A
LOOSELY DEFINED EYEWALL. THE SYSTEM REMAINS LARGE OVERALL AND HAS
YET TO CONSOLIDATE MUCH. ENVIRONMENTAL ANALYSIS INDICATES THAT 14S
IS IN A MARGINALLY FAVORABLE ENVIRONMENT CHARACTERIZED BY MODERATE
POLEWARD OUTFLOW, LOW (5-10 KTS) VERTICAL WIND SHEAR, AND WARM
(26-27 C) SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS PLACED
WITH HIGH CONFIDENCE BASED ON THE EXPOSED LLCC WITHIN THE LARGE EYE
IN THE ANIMATED MSI. THE INITIAL INTENSITY OF 65 KTS IS ASSESSED
WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK AND OBJECTIVE
INTENSITY ESTIMATES LISTED BELOW. ADDITIONALLY, 112332Z RCM-1 SAR
IMAGE REVEALED THE LARGE RADIUS OF MAX WINDS WITH 65-68 KTS WITHIN
THE EASTERN PERIPHERY.

INITIAL WIND RADII BASIS: PERSISTENCE FROM THE MENTIONED SAR DATA.

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR) POSITIONED TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   KNES: T3.5 - 55 KTS
   DEMS: T4.0 - 65 KTS
   FMEE: T4.0 - 65 KTS
   CIMSS ADT: 37 KTS AT 120600Z
   CIMSS AIDT: 55 KTS AT 120600Z
   CIMSS DPRINT: 51 KTS AT 120600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: MODERATE POLEWARD

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 14S IS FORECAST TO CONTINUE TRACKING
SOUTHWESTWARD, ALONG THE STR THROUGHOUT THE FORECAST PERIOD.
REGARDING INTENSITY, 14S IS FORECAST TO MAINTAIN INTENSITY OVER THE
NEXT 12 HOURS. AFTER TAU 12, SEA SURFACE TEMPERATURES BEGIN TO
DROP, CAUSING THE SYSTEM TO WEAKEN. NEAR TAU 72, POLEWARD OUTFLOW
IS EXPECTED TO IMPROVE, ALLOWING 14S TO MAINTAIN INTENSITY THOUGH
THE REMAINDER OF THE FORECAST PERIOD.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
REGARDING THE TRACK OF 14S THROUGH TAU 72 WITH A 190 NM CROSS-TRACK
SPREAD AT THAT TIME. AFTER TAU 72, MODELS BEGIN TO DIVERGE WITH A
445 NM CROSS-TRACK SPREAD AT TAU 120. AS A RESULT, THE JTWC TRACK
FORECAST IS PLACED WITH HIGH CONFIDENCE THROUGH TAU 72 AND MEDIUM
CONFIDENCE THEREAFTER. INTENSITY GUIDANCE IS AGREES ON A GRADUAL
WEAKENING TREND THROUGH TAU 36 AND THEN A STEADY INTENSITY THROUGH
TAU 120. 

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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