WDXS31 PGTW 280300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 03S (THREE) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.6S 90.3E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 1140 NM EAST-SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE (TC) 03S WITH DEEP CONVECTION OBSCURING THE LOW-LEVEL
CIRCULATION CENTER (LLCC), INDICATED BY RAPIDLY COOLING TOPS
OBSERVED ON ENHANCED INFRARED SATELLITE IMAGERY. AROUND THE
PERIPHERY, WELL-DEFINED CONVECTIVE CLOUD LINES HAVE CONTINUED TO
WRAP NEATLY INTO THE OBSCURED LLCC WITH AN EASTWARD EXTENDING
CONVECTIVE CLOUD BAND IN THE SOUTHERN QUADRANT. ON ANIMATED WATER
VAPOR (WV) IMAGERY, STRONG UPPER-LEVEL POLEWARD OUTFLOW HAS BEEN
OBSERVED, WITH A SOUTHWARD EXTENDING CHANNEL AND ASSOCIATED
TRANSVERSE BANDING ON THE POLEWARD EDGE. ADDITIONALLY, NEWLY FORMED
CIRRIFORM STRIATIONS RELATED TO SUPPORTIVE RADIAL OUTFLOW ALOFT IS
EVIDENT ON THE AFOREMENTIONED ANIMATED WV IMAGERY, DESPITE 20 KTS TO
25 KTS OF NORTH-NORTHWEST VERTICAL WIND SHEAR (VWS). THE INITIAL 
POSITION IS PLACED WITH LOW CONFIDENCE BASED ON THE COMPLETELY 
OBSCURED LLCC IN ANIMATED MSI. THE INITIAL INTENSITY OF 40 KTS IS 
ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE T2.5 TO T3.0 AGENCY FIX 
ESTIMATES, WHILE CIMSS OBJECTIVE ESTIMATES RANGE FROM 37 KTS TO 49 
KTS.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: THE WESTERN PERIPHERY OF A
NEAR-EQUATORIAL RIDGE (NER) DIRECTLY TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 47 KTS AT 280100Z
   CIMSS AIDT: 37 KTS AT 280100Z
   CIMSS D-MINT: 38 KTS AT 271922Z
   CIMSS D-PRINT: 40 KTS AT 280100Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 20-25 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: FORMING RADIAL UPPER-LEVEL OUTFLOW.

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   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 03S IS FORECASTED TO TRACK
SOUTH-SOUTHEASTWARD THROUGH TAU 24, ALONG THE WESTERN PERIPHERY OF
THE NER DIRECTLY TO THE EAST. FOLLOWING TAU 24, THE STEERING
ENVIRONMENT FOR TC 03S BECOMES RELATIVELY WEAK, CAUSING THE SYSTEM
TO BECOME QUASI-STATIONARY INTO TAU 48. AFTER TAU 48, A SUBTROPICAL
RIDGE (STR) BECOMES THE DOMINANT STEERING FEATURE, FORCING A
GENERALLY WESTWARD TRACK FOR TC 03S UNTIL THE END OF THE FORECAST
PERIOD. WITH REGARD TO INTENSITY, THE SYSTEM IS EXPECTED TO
MODERATELY INTENSIFY TO 50 KTS OVER THE NEXT 12 HOURS AS STRONG
OUTFLOW ALOFT WILL AID IN CONTINUED STEADY INTENSIFICATION. BETWEEN
TAU 12 AND TAU 24, NORTHWESTERLY VWS IS EXPECTED TO INCREASE,
CAPPING THE MAXIMUM EXPECTED INTENSITIES TO 50 KTS. AFTER TAU 24,
THE ENVIRONMENT BECOMES LARGELY NON-CONDUCIVE FOR TC 03S, BEGINNING
THE INITIAL WEAKENING PHASE. DURING THIS PERIOD, VWS WILL CONTINUE
TO INCREASE ABOVE 30 KTS, SEA SURFACE TEMPERATURES DECREASE TO
BELOW 26 C, AND DRY-AIR WRAPS COMPLETELY INTO THE SYSTEMS CENTRAL
CORE, WEAKENING THE SYSTEM TO 30 KTS BY TAU 72. 

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN MODERATE AGREEMENT
THAT TC 03S WILL TRACK TO THE SOUTH-SOUTHEAST OVER THE NEXT 24 TO
36 HOURS, WITH A CROSS-TRACK SPREAD OF 133 NM BY TAU 36. THE JTWC
FORECAST TRACK IS PLACED CLOSE TO THE MULTI-MODEL CONSENSUS WITH
MEDIUM CONFIDENCE DUE TO THE QUASI-STATIONARY PERIOD NEAR TAU 36.
FOLLOWING THE INITIAL 36 HOURS, CONFIDENCE IN THE JTWC TRACK
FORECAST REMAINS MEDIUM WITH AN INCREASING CROSS-TRACK SPREAD OF
340 NM. INTENSITY GUIDANCE IS IN TIGHT AGREEMENT THAT AN INITIAL
INTENSIFICATION PHASE IS EXPECTED THROUGH TAU 12 AS UPPER-LEVEL
OUTFLOW REMAINS CONDUCIVE FOR FURTHER DEVELOPMENT, FOLLOWED BY A
STEADY WEAKENING PHASE THEREAFTER WITH THE INTRODUCTION OF DRY AIR
AND INTENSE VWS, LENDING HIGH CONFIDENCE TO THE INTENSITY
FORECAST.

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