WDXS32 PGTW 261500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 15S (ANIKA) WARNING 
NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.7S 126.9E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 245 NM WEST-SOUTHWEST OF DARWIN, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A BROAD
SYSTEM WITH TWO REGIONS OF CONVECTION WITH THE LOW LEVEL
CIRCULATION CENTER (LLCC) REMAINING WITH THE EASTERN CONVECTIVE
REGION. THE INITIAL POSITION IS BASED ON EXTRAPOLATION OF A 260950Z
SSMIS 91GHZ IMAGE AND THE WYNDHAM RADAR IMAGERY. THE INTENSITY IS
BASED UPON MULTIPLE AGENCY DVORAK ESTIMATES RANGING FROM T3.0 TO
T3.5, WITH ADT REMAINING THE HIGHEST AT T4.4(75KTS). TC 15S IS
MOVING OVER THE MARSHY KIMBERLEY COAST IN A MARGINALLY FAVORABLE
ENVIRONMENT WITH LOW VERTICAL WIND SHEAR, OFFSET BY WARM SEA
SURFACE TEMPERATURES, MODERATE POLEWARD AND EQUATORWARD OUTFLOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WEAK STEERING ENVIRONMENT FROM A
MID-LEVEL RIDGE TO THE SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   ADRM: T3.0 - 45 KTS
   CIMSS ADT: 75 KTS AT 261210Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 15S HAS CONTINUED MOVING SOUTHWEST OVER THE
LAST 6 HOURS DUE TO THE WEAK STEERING ENVIRONMENT FROM THE
MID-LEVEL RIDGE TO THE SOUTH. OVER THE NEXT 24 HOURS, THE SYSTEM
WILL MAINTAIN THE 50KTS AS IT BRUSHES ACROSS THE NORTHWEST
KIMBERLEY COAST AND TRACKS SLOWLY SOUTH-SOUTHWESTWARD. NEAR TAU 36,
THE SUBTROPICAL RIDGE (STR) TO THE SOUTHEAST WILL BUILD, STEERING
TC 15S TO THE SOUTHWEST ALONG THE KIMBERLEY COAST. THE RIDGE WILL
REORIENT AND PUSH THE SYSTEM SOUTHWEST DOWN THE NORTHWESTERN
AUSTRALIA COAST THROUGH THE REMAINDER OF THE FORECAST OCCASIONALLY
NUDGING TC 15S OFF THE COAST. TC 15S IS EXPECTED TO REMAIN AT
50KTS UNTIL TAU 72 WHERE IT ROUNDS THE RIDGE AXIS AND BEGINS TO TAP
INTO A GREATER POLEWARD OUTFLOW. AT THIS JUNCTURE THE SYSTEM IS
EXPECTED TO CONTINUE TO DEEPEN AND WILL CONTINUE TO INTENSIFY TO A 
PEAK OF 80KTS BY TAU 120.

MODEL DISCUSSION: THERE IS CURRENTLY LOW TRACK AND INTENSITY
CERTAINTY WITH THE FORECAST DUE TO DISPARITY WITHIN THE MODELS.
MODEL GUIDANCE IS STARTING TO TIGHTEN IN THE NEAR TAUS WITH ONLY A
CROSS-TRACK SPREAD OF 175NM BY TAU 72. HOWEVER, THE ALONG TRACK
SPREAD IS LENDING LOW CONFIDENCE AS TO THE TIMING OF WHEN TC 15S
WILL ROUND THE RIDGE AXIS. DUE TO THE TIMING CONSTRAINT, THIS LENDS
LOW CONFIDENCE TO BOTH TRACK AND INTENSITY THROUGH THE FORECAST
PERIOD. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: LOW
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: LOW
   INTENSITY 72-120 HR: LOW//
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