WDXS32 PGTW 260900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 15S (ANIKA) WARNING 
NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.2S 127.2E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 220 NM WEST OF DARWIN, AUSTRALIA
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A BROAD
SYSTEM WITH TWO REGIONS OF CONVECTION WITH THE LOW LEVEL
CIRCULATION CENTER (LLCC) REMAINING TO THE EASTERN CONVECTION
REGION. THE INITIAL POSITION IS BASED LOOSELY ON A 260501Z ATMS
IMAGE. THE INTENSITY IS BASED UPON MULTIPLE AGENCY DVORAK ESTIMATES
RANGING FROM T3.0 TO T3.5, WITH ADT REMAINING THE HIGHEST AT T3.6
(57KTS). TC 15S IS CURRENTLY IN A MARGINALLY FAVORABLE ENVIRONMENT
WITH MODERATE VERTICAL WIND SHEAR, OFFSET BY WARM SEA SURFACE
TEMPERATURES, AND MODERATE RADIAL 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: 57 KTS AT 260540Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL

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 15S HAS MOVED SLIGHTLY TO THE 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 PEAK OUT AT 60KTS AS IT BRUSHES ACROSS THE NORTHWEST KIMBERLEY
COAST AND TRACKS SLOWLY SOUTH-SOUTHWESTWARD. AROUND TAU 36, A
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 WITH THE
POTENTIAL TO NUDGE IT OFF THE COAST BEFORE TAU 72. THE SYSTEM IS
FORECAST TO REMAIN AT 60KTS THROUGH TAUS 24 AND 36, BUT IS EXPECTED
TO DECREASE INTENSITY SLIGHTLY DUE TO THE LAND INTERACTION.
HOWEVER, THE DECREASING TREND WILL REMAIN UNTIL TAU 72 WHEN IT IS
FORECAST TO MOVE BACK OUT OVER OPEN WATER. AFTERWARDS, TC 15S
WILL BEGIN TO DEPART FROM THE COASTLINE AND ONCE AGAIN INCREASE IN
INTENSITY, REACHING 55 KTS BY TAU 120.

MODEL DISCUSSION: THERE IS CURRENTLY LOW TRACK AND INTENSITY
CERTAINTY WITH THE FORECAST DUE TO HIGH DISPARITY WITHIN THE
MODELS. RECENT MODEL RUNS ARE BEGINNING TO MERGE WITH A GENERAL
LONG-TERM FORECAST TRACK TO THE SOUTHWEST DOWN THE AUSTRALIAN COAST
EXCEPT FOR GFS AND ITS ENSEMBLE INDICATING A WESTWARD MOTION. GFS
ALSO REMAINS LOW ON INTENSITY UNTIL AFTER TAU 120, WHILE ALL OTHER
MODELS INTENSIFY THE SYSTEM BY TAU 96 AND BEYOND. THEREFORE, THERE
IS LOW CONFIDENCE IN THE FORECAST INTENSITY.

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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