WDIO31 PGTW 122100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02A (BIPARJOY)  
WARNING NR 027//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.1N 67.3E
   INITIAL INTENSITY: 85 KTS
   GEOGRAPHIC REFERENCE: 282 NM SOUTH OF KARACHI, PAKISTAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS DEEP
CONVECTION RAPIDLY CYCLING AND WRAPPING AROUND THE SOUTHERN AND
EASTERN QUADRANTS OF THE LOW-LEVEL CIRCULATION CENTER (LLCC). A
121621Z GMI 37GHZ MICROWAVE IMAGE REVEALS TIGHTLY-CURVED BANDING
WRAPPING INTO A WELL-DEFINED LLCC, WHICH SUPPORTS THE INITIAL
POSITION WITH HIGH CONFIDENCE. THE GMI 89GHZ MICROWAVE IMAGE
INDICATES THE UPPER-LEVEL CIRCULATION CENTER IS TILTED ABOUT 10NM
WEST-NORTHWEST OF THE LLCC DUE TO MODERATE VERTICAL WIND SHEAR
(VWS). THE PERSISTENT VWS IS OFFSET BY MODERATE WESTWARD OUTFLOW,
WEAK POLEWARD OUTFLOW AND WARM SEA SURFACE TEMPERATURES. THE
INITIAL INTENSITY OF 85 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED
ON THE AGENCY DVORAK ESTIMATES AS WELL AS THE CIMSS ADT ESTIMATE.
ADDITIONALLY, THE INITIAL INTENSITY IS SUPPORTED BY THE 121616Z
D-MINT ESTIMATE OF 83 KNOTS AND THE 121800Z D-PRINT ESTIMATE OF 91
KNOTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   KNES: T4.5 - 77 KTS
   DEMS: T5.0 - 90 KTS
   CIMSS SATCON: 80 KTS AT 121634Z
   CIMSS ADT: 82 KTS AT 121830Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 20-25 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE WESTWARD

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: TROPICAL CYCLONE (TC) 02A HAS REMAINED
RESILIENT AND HAS FLIRTED WITH A WEAK EYE OVER THE PAST SIX HOURS
WHICH MAKES THE SHORT-TERM INTENSITY FORECAST CHALLENGING. BASED ON
THE EYE FORMATION POSSIBILITY, EXCELLENT LOW-LEVEL STRUCTURE AND 
GENERALLY FAVORABLE CONDITIONS, A SLIGHT INTENSIFICATION TO 90 KNOTS 
IS EXPECTED BY TAU 12 WITH A SLOW WEAKENING TREND AFTER TAU 12 
THROUGH TAU 48. AFTER TAU 48, TC 02A WILL RECURVE NORTHEASTWARD AND 
WILL MAKE LANDFALL BY TAU 72 NEAR THE PAKISTAN-INDIA BORDER. RAPID 
WEAKENING IS EXPECTED AFTER TAU 48 WITH DISSIPATION OCCURRING AS THE 
SYSTEM TRACKS INLAND.  

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN FAIR
AGREEMENT WITH A 165NM SPREAD IN GUIDANCE AT LANDFALL NEAR THE
PAKISTAN-INDIA BORDER REGION. IN GENERAL, THE 121200Z ECMWF AND GFS
ENSEMBLES INDICATE A SIMILAR SPREAD OF SOLUTIONS THUS THERE IS
MEDIUM OVERALL CONFIDENCE IN THE JTWC TRACK FORECAST. MUCH OF THE
RELIABLE INTENSITY GUIDANCE INDICATES A FLAT OR SLOW WEAKENING
TREND OVER THE NEXT 12 HOURS WITH MORE SIGNIFICANT WEAKENING AFTER
TAU 12. HWRF AND GFS, HOWEVER, SHOW MODEST INTENSIFICATION WITH A
PEAK INTENSITY RANGING FROM 95 TO 105 KNOTS WITHIN THE NEXT 36
HOURS. THE 121200Z COAMPS-TC ENSEMBLE INDICATES INCREASING
PROBABILITY (10 TO 80 PERCENT) OF MODERATE INTENSIFICATION OVER THE
NEXT 36 HOURS.

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