WDIO31 PGTW 150300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02A (BIPARJOY) 
WARNING NR 036//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.6N 66.8E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 132 NM SOUTH OF KARACHI, PAKISTAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 26 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THAT TC
02A CONTINUES TO DETERIORATE AND BECOMING INCREASINGLY ASYMMETRIC.
CONVECTION CONTINUES TO FIRE ALONG THE SOUTHERN PERIPHERY WHILE THE
NORTHERN HALF OF THE SYSTEM IS RELATIVELY DEVOID OF SIGNIFICANT
CONVECTIVE ACTIVITY. A 142314Z SSMIS 37GHZ IMAGE SHOWED A BROAD
CURVED BAND OF DEEP CONVECTION TO THE SOUTH OF A RELATIVELY WEAK
LOW EMISSIVITY REGION (LER), WHICH MARKED THE LOW LEVEL CIRCULATION
CENTER (LLCC). THE INITIAL POSITION WAS THUS ASSESSED WITH HIGH
CONFIDENCE. THE INITIAL INTENSITY IS REDUCED TO 60 KNOTS, ROUGHLY
MIDWAY BETWEEN THE T3.5 DVORAK INTENSITY ESTIMATES FROM PGTW AND
KNES, AND THE T4.0 FROM DEMS, THOUGH IT IS SIGNIFICANTLY HIGHER
THAN THE OBJECTIVE ESTIMATES, TO ACCOUNT FOR SPIN-DOWN TIME. THE
SYSTEM HAS TURNED A HAIR TO THE EAST OF DUE NORTH BASED ON
SATELLITE ANIMATIONS AND RADAR DATA FROM KARACHI. NO MAJOR CHANGES
HAVE BEEN NOTED IN THE ENVIRONMENT, STILL CHARACTERIZED BY HIGH
EAST-NORTHEAST WIND SHEAR, STRONG WESTWARD AND EQUATORWARD OUTFLOW
AND WARM SSTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: COMBINATION OF SUBTROPICAL RIDGE (STR)
OVER INDIA AND A SECOND STR CENTERED OVER THE STRAIT OF HORMUZ. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   DEMS: T4.0 - 65 KTS
   CIMSS SATCON: 51 KTS AT 142131Z
   CIMSS ADT: 35 KTS AT 150000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 25-30 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG WESTWARD
   OTHER FACTORS: DRY MID-LEVEL AIR ENTRENCHED TO THE NORTH. 

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: NO MAJOR CHANGES FROM THE PREVIOUS FORECAST
ARE EXPECTED DURING THE SHORT DURATION OF THE FORECAST PERIOD. TC
02A IS FORECAST TO TURN ONTO A MORE NORTHEASTWARD TRAJECTORY
THROUGH THE NEXT 12 HOURS AS THE STR OVER INDIA WEAKENS AND RECEDES
TO THE SOUTHEAST, WHILE THE RIDGE OVER THE STRAIT OF HORMUZ BUILDS
EASTWARD ACROSS SOUTHERN PAKISTAN. TC 02A IS EXPECTED TO MAKE
LANDFALL IN A LITTLE MORE THAN 12 HOURS FROM NOW JUST EAST OF THE
PAKISTAN-INDIA BORDER REGION BEFORE MOVING QUICKLY INLAND ACROSS
THE RANN OF KUTCH, WHERE IT WILL ULTIMATELY DISSIPATE. WHILE THE
SYSTEM WILL REMAIN IN A GENERALLY UNFAVORABLE ENVIRONMENT THROUGH
THE NEXT 12 HOURS, NO MAJOR CHANGES TO THE CURRENT INTENSITY ARE
EXPECTED AS THE INERTIA WILL TAKE TIME TO SPIN DOWN. LANDFALL
INTENSITY IS FORECAST FOR 60 KNOTS. ONCE ASHORE, THE SYSTEM WILL
RAPIDLY WEAKEN AND FULLY DISSIPATE NO LATER THAN TAU 48. 

MODEL DISCUSSION: TRACK GUIDANCE IS IN GOOD AGREEMENT THROUGH THE
SHORT FORECAST PERIOD, WITH ALL CONSENSUS MEMBERS EXCEPT NAVGEM AND
GALWEM ENCAPSULATED WITHIN A VERY TIGHT, 50NM ENVELOPE AT LANDFALL.
THE NAVGEM AND GALWEM CONTINUE TO PUSH THE SYSTEM ONTO A MORE
NORTHERLY TRAJECTORY, WITH LANDFALL AT THE BORDER, THEN MOVING
INLAND PARALLEL TO THE BORDER. HOWEVER THESE TRACKS ARE CONSIDERED
UNLIKELY AND ARE THUS DISCOUNTED, WITH THE JTWC FORECAST LAID DOWN
ALONG THE NORTHERN EDGE OF THE GUIDANCE ENVELOPE WITH HIGH
CONFIDENCE. INTENSITY GUIDANCE FOR THE MOST PART IS IN AGREEMENT ON
A STEADY INTENSITY THROUGH LANDFALL FOLLOWED BY RAPID WEAKENING.
HOWEVER THE GFS AND COAMPS-TC BELIEVE THE SYSTEM WILL INTENSIFY
10-15 KNOTS PRIOR TO LANDFALL. CONSIDERING THE DRY AIR, AND HIGH
SHEAR, THIS IS NOT LIKELY AND THE JTWC FORECAST LIES CLOSE TO THE
CONSENSUS MEAN WITH HIGH CONFIDENCE. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: HIGH//
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