WDIO31 PGTW 090900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02A (BIPARJOY)   
WARNING NR 013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.1N 66.8E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 557 NM SOUTHEAST OF MASIRAH ISLAND
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN IRREGULAR
CENTRAL DENSE OVERCAST FEATURE OBSCURING MUCH OF THE LOW-LEVEL
CIRCULATION (LLC). MSI ALSO REVEALS SOME EXPOSED LOW-LEVEL BANDS
OVER THE EASTERN SEMICIRCLE DUE TO PERSISTENT EASTERLY VERTICAL
WIND SHEAR (VWS), WHICH IS HINDERING DEVELOPMENT. A TIMELY 090534Z 
ASCAT-B BULLSEYE IMAGE SHOWS A SYMMETRIC CIRCULATION WITH 50-55 KNOT 
WINDS OVER THE SOUTHEAST QUADRANT OF A WELL-DEFINED CENTER, WHICH 
SUPPORTS THE INITIAL POSITION WITH HIGH CONFIDENCE. THE INITIAL 
INTENSITY OF 65 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON AN 
AIDT OBJECTIVE ESTIMATE OF 66 KNOTS AT 090600Z AS WELL AS THE PGTW AND 
KNES DVORAK ESTIMATES.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) POSITIONED TO
THE EAST OVER WESTERN INDIA 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   KNES: T4.0 - 65 KTS
   CIMSS SATCON: 65 KTS AT 090254Z
   CIMSS ADT: 55 KTS AT 090300Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 20-25 KTS
   SST: 31-32 CELSIUS
   OUTFLOW: MODERATE WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: HIGH

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 02A IS STRUGGLING TO
CONSOLIDATE DUE TO THE PERSISTENT MODERATE TO HIGH EASTERLY VWS.
MODERATE WESTWARD OUTFLOW AND VERY WARM SEA SURFACE TEMPERATURES
HAVE HELPED MAINTAIN THE CORE CONVECTION AND A WEAK CDO. THIS VWS
IS EXPECTED TO RELAX WITHIN THE NEXT 12 TO 24 HOURS, WHICH SHOULD
ALLOW TC 02A TO RE-INTENSIFY TO ABOUT 90 KNOTS BY TAU 36 AS IT
TRACKS SLOWLY POLEWARD ALONG THE WESTERN PERIPHERY OF THE STR.
AFTER TAU 36, VWS IS FORECAST TO INCREASE WITH UPPER-LEVEL
EASTERLIES STRENGTHENING SOUTH OF A BUILDING RIDGE TO THE NORTH.
THIS IS EXPECTED TO PRODUCE A STEADY WEAKENING TREND THROUGH TAU
120 AS THE SYSTEM CONTINUES TO SLOWLY TRACK NORTH-NORTHWESTWARD
INTO THE NORTHERN ARABIAN SEA.   

MODEL DISCUSSION: IN GENERAL, DETERMINISTIC GUIDANCE HAS COME INTO
BETTER AGREEMENT WITH GFS AND NAVGEM, IN PARTICULAR, ALIGNED CLOSER
TO THE ECMWF AND ECMWF ENSEMBLE MEAN SOLUTIONS. HOWEVER, THERE IS
STILL A 154NM CROSS-TRACK SPREAD IN SOLUTIONS AT TAU 72 AND A LARGE 
370NM CROSS-TRACK SPREAD IN SOLUTIONS AT TAU 120 REFLECTING INCREASING 
UNCERTAINTY (LOW CONFIDENCE) IN THE EXTENDED JTWC FORECAST TRACK. THE 
090000Z ECMWF AND GFS ENSEMBLES ARE ALSO BETTER ALIGNED BUT ALSO 
REFLECT INCREASING UNCERTAINTY IN THE TRACK FORECAST AFTER TAU 72. 
THERE IS ALSO MEDIUM CONFIDENCE IN THE JTWC INTENSITY FORECAST THROUGH 
TAU 72 WITH A LARGE SPREAD IN RELIABLE INTENSITY GUIDANCE. HWRF
INDICATES A PEAK OF 110 KNOTS NEAR TAU 60 BUT IS SUSPECT DUE TO ITS
OUTLIER TRACK TOWARD NORTHERN OMAN. SEVERAL MODELS HAVE INDICATED
AND CONTINUE TO INDICATE SOME POTENTIAL FOR A SHORT PERIOD OF RAPID
INTENSIFICATION WITHIN THE NEXT 36 HOURS WHICH HAS YET TO
MATERIALIZE BUT REMAINS POSSIBLE IF VWS DECREASES. THE COAMPS-TC
ENSEMBLE INDICATES INCREASING PROBABILITIES OF RAPID INTENSIFICATION 
FROM 60 TO 90 PERCENT DURING THE NEXT 36 HOURS.  

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