WDIO31 PGTW 060300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02A (SHAKHTI) WARNING 
NR 013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.8N 60.6E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 108 NM EAST-SOUTHEAST OF MASIRAH ISLAND
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A FULLY
EXPOSED LOW-LEVEL CIRCULATION (LLC), WITH RAPIDLY DETERIORATING
CONVECTION SHEARED TO THE WEST. DESPITE THE LACK OF DEEP CONVECTION, 
THE LLC IS TIGHTLY WRAPPED WITH A WELL-DEFINED CENTER. ENVIRONMENTAL 
CONDITIONS HAVE DEGRADED, WITH HIGH VERTICAL WIND SHEAR AND EXTENSIVE 
DRY AIR. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON 
THE EIR SATELLITE IMAGERY. THE INITIAL INTENSITY OF 50 KTS IS 
ASSESSED WITH MEDIUM CONFIDENCE BASED ON A BLEND OF AGENCY AND CIMSS 
DVORAK ESTIMATES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: LOW- TO MID-LEVEL SUBTROPICAL RIDGE (STR) 
TO THE WEST AND BUILDING TO THE SOUTHWEST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   CIMSS SATCON: 47 KTS AT 052230Z
   CIMSS ADT: 43 KTS AT 052330Z
   CIMSS AIDT: 43 KTS AT 052330Z
   CIMSS D-PRINT: 44 KTS AT 052330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 20-25 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

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: TROPICAL CYCLONE (TC) 02A HAS STALLED, DRIFTING 
SLOWLY EAST-SOUTHEASTWARD, AND IS FORECAST TO TRACK GENERALLY 
SOUTHEASTWARD UNDER THE STEERING INFLUENCE OF THE LOW-LEVEL STEERING 
RIDGE TO THE WEST AND SOUTH. THE SYSTEM WILL WEAKEN RAPIDLY DUE TO 
EXTENSIVE DRY AIR ENTRAINING INTO THE SYSTEM AT ALL LEVELS AND 
MODERATE TO HIGH VERTICAL WIND SHEAR. THE SYSTEM IS EXPECTED TO 
DISSIPATE BY TAU 36.

MODEL DISCUSSION: DETERMINISTIC AND PROBABILISTIC GUIDANCE IS IN FAIR 
AGREEMENT SUPPORTING THE JTWC TRACK FORECAST WITH MEDIUM CONFIDENCE. 
RELIABLE INTENSITY GUIDANCE SUPPORTS THE RAPID WEAKENING FORECAST DUE 
TO THE VERY DRY ENVIRONMENT AND HIGH VERTICAL WIND SHEAR.  

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