WDPS32 PGTW 032100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 16P (KEVIN) WARNING NR 
009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.6S 169.9E
   INITIAL INTENSITY: 105 KTS
   GEOGRAPHIC REFERENCE: 146 NM SOUTHEAST OF PORT VILA, VANUATU
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 45 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE 16P (KEVIN) CONTINUED TO STEADILY INTENSIFY AS IT
HAS PASSED OVER OR VERY NEAR THE ISLANDS OF ERROMANGO AND TANNA.
NOW THAT IT IS BACK OVER OPEN WATERS AND CLEAR OF THE DISRUPTION
CAUSED BY THE ISLANDS, THE SYSTEM HAS KICKED IT UP A NOTCH IN TERMS
OF STRUCTURE AND INTENSITY. RECENT ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY DEPICTS A NASCENT EYE BEGINNING TO APPEAR AND
REAL-TIME LIGHTNING DATA INDICATES AN ONGOING INNER CORE LIGHTNING
BURST. BY 031900Z, VORTICAL HOT TOWERS WITH CLOUD TOP TEMPERATURES
OF -90C OR COLDER HAVE BEGUN TO WRAP COMPLETELY AROUND THE
DEVELOPING EYE. A 031617Z GMI MICROWAVE PASS SHOWED A SMALL
LOW-LEVEL EYE IN THE 37GHZ BAND, WHILE THE WELL-DEFINED UPPER-LEVEL
MICROWAVE EYE WAS DISPLACED ABOUT 10NM TO THE SOUTHEAST AND A
031732Z SSMIS MICROWAVE PASS INDICATES THE EYEWALL IS NOW
COMPLETELY CLOSED. THE INITIAL POSITION IS ASSESSED WITH HIGH
CONFIDENCE BASED ON THE MICROWAVE IMAGERY NOTED ABOVE. THE INITIAL
INTENSITY IS ASSESSED WITH HIGH CONFIDENCE BASED ON A BLEND OF
AGENCY DVORAK CURRENT INTENSITY ESTIMATES AND OBJECTIVE ESTIMATES
INCLUDING THE SATCON (105 KTS), DEEP MICRONET (104 KTS) AND
OPEN-AIIR (110 KTS). ENVIRONMENTAL CONDITIONS REMAIN CONDUCIVE,
WITH LOW (5-10 KTS) VWS, WARM (28-29C) SSTS AND ROBUST POLEWARD
OUTFLOW, ENHANCING A MESOSCALE POINT SOURCE DIRECTLY OVER TOP OF
THE SYSTEM.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) TO THE EAST-NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   KNES: T6.0 - 115 KTS
   PHFO: T5.5 - 102 KTS
   CIMSS SATCON: 105 KTS AT 031348Z
   CIMSS ADT: 107 KTS AT 031730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: MESOSCALE ANTICYCLONE ALOFT DIRECTLY OVER THE
CENTER, PROVIDING SMALL-SCALE RADIAL OUTFLOW.

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   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 16P (KEVIN) IS PICKING UP SPEED NOW AS IT
CLEARS THE ISLANDS OF VANUATU, TRACKING SOUTHEASTWARD ALONG THE
WESTERN SIDE OF A MASSIVE DEEP-LAYER STR CENTERED SOUTH OF SAMOA.
NO SIGNIFICANT CHANGE IN THE STEERING MECHANISM IS EXPECTED, AND
THE SYSTEM WILL CONTINUE TO TRACK GENERALLY SOUTHEASTWARD THROUGH
THE ENTIRETY OF THE FORECAST PERIOD. SOME SLOWING OF TRACK SPEEDS
IS EXPECTED LATE IN THE FORECAST AS THE GRADIENT SLACKENS A BIT.
THE ENVIRONMENT IS RIPE FOR ADDITIONAL INTENSIFICATION, THOUGH THE
SYSTEM IS NOW PASSING OVER WATERS WHICH HAVE BEEN STIRRED UP BY TC
15P (JUDY) AND SO AVAILABLE OCEAN HEAT CONTENT (OHC) IS SOMEWHAT
LOW. BUT THE GOOD TIMES WILL NOT LAST AS TC 16P HAS ONLY ANOTHER
12 HOURS OR SO BEFORE CONDITIONS BEGIN TO DETERIORATE. THE SYSTEM
WILL FIRST BE IMPACTED BY A DRAMATIC INCREASE IN VWS, WHICH BEGINS
PUNCHING IN FROM THE WEST BY TAU 18. SHEAR IS EXPECTED TO INCREASE
UP TO 35 KNOTS OR MORE BY TAU 24, LEADING A RAPID DETERIORATION IN
THE CORE STRUCTURE AND SUBSEQUENT WEAKENING. BY TAU 24, THE SYSTEM
WILL CROSS THE 26C ISOTHERM AND MOVE INTO COOLER WATERS, AND AT THE
SAME TIME BEGIN TO BE SMOTHERED BY MID-LEVEL DRY AIR MOVING IN FROM
THE WEST. THIS WILL ACCELERATE THE WEAKENING PROCESS AND MARK THE
BEGINNING OF SUBTROPICAL TRANSITION (STT). THE SYSTEM IS EXPECTED
TO TRANSITION TO A NEAR-STORM FORCE SUBTROPICAL LOW BY TAU 48. 

MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE IS IN
VERY TIGHT AGREEMENT THROUGH THE FORECAST PERIOD, WITH SPREAD
INCREASING MODESTLY TO JUST 90NM BY TAU 48. THE JTWC FORECAST
REMAINS CONSISTENT WITH THE PREVIOUS FORECASTS AND TRACKS JUST
SOUTH OF THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE. INTENSITY
GUIDANCE IS MIXED, WITH THE HWRF AND GFS SHOWING NO RESPECT FOR KEVIN, 
AND INDICATING RAPID WEAKENING FROM TAU 00. MEANWHILE THE COAMPS-TC 
(GFS VERSION) AND TO A LESSER EXTENT THE DECAY-SHIPS (GFS) INDICATE 
NEAR-TERM INTENSIFICATION, PEAKING AT 115 KTS AT TAU 12, FOLLOWED BY 
RAPID WEAKENING THROUGH THE REMAINDER OF THE FORECAST. THE JTWC 
FORECAST CONCURS WITH THE NEAR-TERM INTENSIFICATION AND PEAKS AT 115 
KNOTS AT TAU 12, THEN MERGES WITH THE CONSENSUS MEAN BY TAU 36 ON THE 
DOWNWARD TREND WITH HIGH CONFIDENCE. 
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: HIGH//
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