WDPS32 PGTW 050900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 16P (KEVIN) WARNING NR 
015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 26.9S 176.6W
   INITIAL INTENSITY: 75 KTS
   GEOGRAPHIC REFERENCE: 596 NM SOUTH-SOUTHEAST OF SUVA, FIJI
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 36 KTS
   SIGNIFICANT WAVE HEIGHT: 35 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICT DISORGANIZED
CONVECTION BECOMING DISPLACED TO THE SOUTHEAST OF THE LOW LEVEL
CIRCULATION CENTER (LLCC). A 050549Z SSMIS 91GHZ IMAGE SHOWS DEEP
CONVECTIVE ACTIVITY IN THE SOUTHERN PERIPHERY DECOUPLED FROM THE
LLCC TO THE NORTHWEST. TC KEVIN IS IN AN UNFAVORABLE ENVIRONMENT
FOR ANY FURTHER TROPICAL DEVELOPMENT. THESE CONDITIONS ARE
CHARACTERIZED BY STRONG POLEWARD OUTFLOW ALOFT, OFFSET BY STRONG
(30-40 KTS) VERTICAL WIND SHEAR (VWS), A STRETCHED OUT, ASYMMETRIC
850 MB VORTICITY SIGNATURE, AND COOLER (25-26 C) SEA SURFACE
TEMPERATURES (SST). THE INITIAL POSITION IS PLACED WITH MEDIUM
CONFIDENCE BASED ON THE AFOREMENTIONED MSI AND MULTI-AGENCY FIX
LOCATIONS. THE INITIAL INTENSITY OF 75 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE, SET LOWER THAN SUBJECTIVE AND AUTOMATED DVORAK
ESTIMATES. THIS IS DUE TO THE OVERALL DECAYING STRUCTURE ANALYZED
IN THE ABOVE MENTIONED IMAGERY.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   KNES: T5.0 - 90 KTS
   NZKL: T5.0 - 90 KTS
   CIMSS SATCON: 81 KTS AT 050108Z
   CIMSS ADT: 82 KTS AT 050530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 30+ KTS
   SST: 25-26 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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 KEVIN IS CURRENTLY IN SUBTROPICAL
TRANSITION AND IS EXPECTED TO COMPLETE THIS TRANSITION IN THE NEAR
FUTURE. TC KEVIN CONTINUES ITS SOUTHEASTWARD TRACK AS IT HUGS THE
OUTER PERIPHERY OF STR TO THE NORTHEAST. BY TAU 12, TC KEVIN WILL
DECREASE IN INTENSITY TO 55 KNOTS AS A RESULT OF ENTERING A MORE
HOSTILE ENVIRONMENT CHARACTERIZED BY STRONGER (40-50 KTS) VWS AND
LOWER (23-24 C) SSTS. ALSO AT THIS TIME, TC KEVIN WILL START TO
FEEL THE EFFECTS OF DRY AIR ENTRAINMENT FROM THE WEST-NORTHWEST
BEING WRAPPED INTO THE CENTER. BY TAU 24, THE SYSTEM WILL BECOME
FULLY SUBTROPICAL.

MODEL DISCUSSION: THE JTWC TRACK CONSENSUS MEMBERS ARE IN EXTREMELY
TIGHT AGREEMENT SHOWING A CONTINUOUS SOUTHEASTWARD TRAJECTORY. THE
FORECAST MODEL ENVELOPE HAS A 25 NM SPREAD BY TAU 12 WHICH
PROGRESSIVELY INCREASES TO 75 NM BY TAU 24. AS A RESULT, THE JTWC
FORECAST TRACK IS SET WITH HIGH CONFIDENCE. THE JTWC INTENSITY
CONSENSUS MEMBERS ARE ALSO IN GOOD AGREEMENT SHOWING A DECREASING
TREND AS THE SYSTEM MAKES ITS SUBTROPICAL TRANSITION.

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