WDIO31 PGTW 050300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02A (SHAKHTI) WARNING 
NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.0N 61.3E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 145 NM EAST-NORTHEAST OF MASIRAH ISLAND
   MOVEMENT PAST 6 HOURS: WESTWARD AT 11 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS DEEP
CONVECTION TILTED SOUTHEASTWARD OF THE LOW-LEVEL CIRCULATION CENTER
(LLCC) OF TROPICAL CYCLONE (TC) 02A. THE VERTICAL TILT WITH HEIGHT
IS DUE TO HIGH VERTICAL WIND SHEAR AND ACCOMPANYING DRY AIR FROM
THE NORTHWEST. THE INITIAL POSITION IS PLACED WITH LOW CONFIDENCE
BASED ON THE OBSCURED LOW-LEVEL CENTER BELOW THE DEEP CONVECTION
DEPICTED IN THE AFOREMENTIONED ANIMATED EIR. THE INITIAL INTENSITY
OF 70 KTS IS ASSESSED WITH LOW CONFIDENCE BASED ON THE AGENCY AND
OBJECTIVE FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT BETWEEN
TWO DEEP LAYER RIDGES

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   KNES: T4.5 - 77 KTS
   DEMS: T3.5 - 55 KTS
   CIMSS SATCON: 66 KTS AT 042150Z
   CIMSS ADT: 72 KTS AT 050000Z
   CIMSS AIDT: 81 KTS AT 042000Z
   CIMSS D-MINT: 66 KTS AT 050016Z
   CIMSS D-PRINT: 70 KTS AT 050000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 15-20 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 02A WILL WEAKLY TRACK SOUTHWESTWARD FOR THE
NEXT 24 HOURS WHILE REMAINING IN A COMPETING STEERING ENVIRONMENT.
AFTER TAU 24, A DEEP-LAYER TROUGH WILL WEAKEN THE STEERING RIDGE TO
THE SOUTHEAST, RESULTING IN A BRIEF QUASI STATIONARY PERIOD BEFORE
THE SYSTEM CURVES SOUTHEASTWARD THROUGH THE REMAINDER OF THE
FORECAST PERIOD. HIGH VERTICAL WIND SHEAR AND DRY AIR WILL CONTINUE
TO ERODE THE STRUCTURE OF TC 02A AND WEAKENING WILL CONTINUE FOR
THE REMAINDER OF THE FORECAST PERIOD. UPWELLING WILL INCREASE THE
RATE OF WEAKENING AS THE TRACK SPEED SLOWS. ULTIMATELY, TC 02A WILL
DISSIPATE BY THE END OF THE FORECAST PERIOD. 

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN MODERATE
AGREEMENT THAT TC 02A WILL TRACK SOUTHWESTWARD SLOWLY OVER THE NEXT
24-36 HOURS, FOLLOWED BY A SLOW AND GRADUAL CURVE TOWARDS THE
EASTWARD DIRECTION. EXCLUDING OUTLIERS OF GFS AND NAVGEM, THERE IS
AN APPROXIMATELY 50NM CROSS-TRACK SPREAD BY THE END OF THE FORECAST
PERIOD. THE INTENSITY GUIDANCE FOLLOWS SUIT AND IS IN HIGH
AGREEMENT THAT WEAKENING WILL BE CONTINUOUS WHILE IN UNFAVORABLE
CONDITIONS AND DISSIPATION WILL OCCUR BETWEEN TAU 36-60.

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