WDPS31 PGTW 102100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 13P (KOJI) WARNING NR 
003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.3S 147.9E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 187 NM SOUTHEAST OF CAIRNS, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A BROAD
ROTATION, EXHIBITING ASPECTS OF A MONSOON DEPRESSION TYPE SYSTEM,
WITH A SMALL INNER-CORE OF DEEP CONVECTION NOW DEVELOPING JUST
OFFSHORE OF BOWEN. ANIMATED RADAR DATA SUGGESTS THE LOW LEVEL
CIRCULATION CENTER (LLCC) IS SEPARATED FROM THE MID-LEVEL VORTEX
ASSOCIATED WITH THE DEEP CONVECTION, WHICH IS MUCH CLOSER TO THE
COASTLINE. SURFACE OBSERVATIONS FROM ALVA BEACH AND BOWEN INDICATE
THE LLCC REMAINS OFFSHORE AS OF THE 1800Z HOUR. A 101812Z SSMIS
89GHZ MICROWAVE IMAGE-BASED ARCHER ANALYSIS PLACES THE LLCC EAST OF
ALVA BEACH AS WELL. THE HIGHEST WINDS ASSOCIATED WITH THE SYSTEM
ARE LOCATED ON THE EASTERN PERIPHERY BASED ON SURFACE OBSERVATIONS
OVER THE COURSE OF THE PAST 24 HOURS. HOWEVER, OBSERVATIONS FROM
HAMILTON BAY HAVE CONSISTENTLY BEEN ABOVE 40-45 KNOTS, LIKELY DUE
TO THE EXPOSED NATURE OF THE OBSERVATION SITE. THE INITIAL POSITION
IS THUS ASSESSED WITH HIGH CONFIDENCE BASED ON THE AGREEMENT OF THE
VARIOUS OBJECTIVE AND SUBJECTIVE ANALYSES ABOVE. THE INITIAL
INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE, BIASED TOWARDS THE
HIGHER END OF THE OBJECTIVE AND SUBJECTIVE ESTIMATES NOTED BELOW.
ENVIRONMENTAL CONDITIONS ARE MARGINAL FAVORABLE, WITH LOW VWS, WARM
SSTS AND GOOD POLEWARD OUTFLOW, OFFSET BY PROXIMITY TO LAND AND THE
BROAD NATURE OF THE VORTEX.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   ABRF: T1.5 - 25 KTS
   CIMSS SATCON: 45 KTS AT 101830Z
   CIMSS ADT: 37 KTS AT 101730Z
   CIMSS AIDT: 33 KTS AT 101730Z
   CIMSS D-MINT: 27 KTS AT 101529Z
   CIMSS D-PRINT: 31 KTS AT 101730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: PROXIMITY TO LAND, MONSOONAL DEPRESSION
STRUCTURE. 

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) 13P HAS CONTINUED TO
SLOWLY CONSOLIDATE, WITH A STEADILY DECREASING RADIUS OF MAXIMUM
WINDS (RMW) OVER THE PAST SIX HOURS, AS IT APPROACHES THE COASTLINE
NORTHWEST OF BOWEN, AUSTRALIA. THE SYSTEM IS TRACKING ALONG THE
WESTERN SIDE OF A DEEP-LAYER STR TO THE EAST. NO SIGNIFICANT
CHANGES IN THE STEERING PATTERN ARE EXPECTED OVER THE SHORT
DURATION OF THE FORECAST PERIOD. THE SYSTEM HAS SLOWED DOWN OVER
THE PAST COUPLE OF HOURS AS IT HAS MOVED CLOSER TO THE COASTLINE,
BUT IS STILL EXPECTED TO MAKE LANDFALL WITHIN THE NEXT FEW HOURS.
NO ADDITIONAL INTENSIFICATION IS FORECAST BEFORE THE SYSTEM MAKES
LANDFALL AND ONCE ASHORE, TC 13P WILL QUICKLY DISSIPATE WITHIN
24-36 HOURS. 

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN GOOD
AGREEMENT, SUPPORTING A SOUTHWESTWARD TRACK UNTIL LANDFALL, THEN A
GRADUAL TURN TO A MORE WESTWARD TRACK THROUGH DISSIPATION. SEVERAL
MEMBERS OF THE CONSENSUS, INCLUDING NAVGEM, GFS, GEFS AND EC-AIFS,
TURN THE REMNANTS OF TC 13P ONTO A MORE NORTHWESTWARD TRACK AFTER
TAU 24, WHILE THE REMAINDER OF THE MODELS CONTINUE IT ALONG A
STRAIGHT SOUTHWESTWARD TRACK. INTENSITY GUIDANCE IS IN GOOD
AGREEMENT ON A STEADY WEAKENING TREND THROUGH THE FORECAST PERIOD. 

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