WDPS31 PGTW 101500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 13P (KOJI) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.9S 148.0E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 140 NM EAST-SOUTHEAST OF CAIRNS, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE 13P (KOJI) WITH FRAGMENTED CONVECTIVE BANDING ALONG THE
NORTHERN SEMICIRCLE OF A BROAD LOW-LEVEL CIRCULATION CENTER (LLCC).
13P CONTINUES TO HAVE A CORE OF WEAKER WINDS WITH STRONGER WINDS
ALONG THE PERIPHERY. THE RADIUS OF MAXIMUM WINDS APPEARS TO BE
FURTHER CONTRACTING AS IT APPROACHES THE COAST. THE INITIAL
POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE PARTIALLY
EXPOSED CENTER IN ANIMATED EIR IMAGERY. THE INITIAL INTENSITY OF 45
KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED PRIMARILY ON NEARBY
SURFACE OBSERVATIONS RANGING FROM 35-40 KTS. ADDITIONALLY, A
PARTIAL 101113Z METOP-C ASCAT PASS SHOWED NON-FLAGGED 40 KNOT BARBS
WITHIN THE EASTERN PERIPHERY OF THE CIRCULATION. AGENCY DVORAK
ESTIMATES ARE SLIGHTLY UNDERESTIMATING THE CURRENT INTENSITY DUE TO
THE GENERALLY WEAK CONVECTIVE SIGNATURE COMPARED TO THE SURFACE
CIRCULATION STRENGTH.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: RIDGING TO THE EAST AND SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   ABRF: T1.5 - 25 KTS
   CIMSS ADT: 43 KTS AT 101200Z
   CIMSS AIDT: 36 KTS AT 101200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: BROAD WIND FIELD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   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 13P IS FORECAST TO SOUTH-SOUTHWESTWARD
THROUGH TAU 24 WITH LANDFALL CURRENTLY EXPECTED TO OCCUR NEAR TAU
12, CLOSE TO TOWNSVILLE CITY. THE 34-KNOT WIND RADII ARE FORECAST
TO FURTHER CONTRACT AS THE SYSTEM APPROACHES THE COAST. AFTER TAU
24, 13P IS FORECAST TO TURN WESTWARD AS A SUBTROPICAL RIDGE
CENTERED OVER WESTERN AUSTRALIA BEGINS TO INTERACT WITH THE SYSTEM.
REGARDING INTENSITY, 13P IS FORECAST TO MAINTAIN INTENSITY OVER THE
NEXT 6 HOURS OR SO BEFORE IT BEGINS TO FEEL TERRAIN EFFECTS. AFTER
MAKING LANDFALL, 13P WILL STEADILY WEAKEN IN RESPONSE TO A
COMBINATION OF TERRAIN INTERACTION AND DRY AIR FROM CENTRAL
AUSTRALIA IMPACT THE VORTEX. DISSIPATION IS FORECAST TO OCCUR NEAR
TAU 36 AS THE SYSTEM TRACKS FURTHER INLAND INTO THE QUEENSLAND
REGION. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT WITH NO SIGNIFICANT OUTLIERS THROUGHOUT THE FORECAST
PERIOD. AS A RESULT, THE JTWC TRACK FORECAST IS PLACED CLOSE TO THE
MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE. INTENSITY GUIDANCE
AGREES ON WEAKENING FROM TAU 12 ONWARD WITH LITTLE VARIABILITY,
LENDING HIGH CONFIDENCE TO THE JTWC INTENSITY FORECAST.

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