WDIO31 PGTW 150900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02A (BIPARJOY) WARNING 
NR 037//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.7N 67.2E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 126 NM SOUTH OF KARACHI, PAKISTAN
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A VERTICALLY
DECOUPLED CIRCULATION, AS THE LLCC STEAMS TOWARDS THE COAST OF
INDIA AND THE UPPER LEVEL FEATURES LAG BEHIND. NEARLY THE ENTIRE
NORTHERN SEMICIRCLE OF THE CIRCULATION IS ENGULFED IN DRY AIR
PARTIALLY REVEALING THE LLCC. A RECENT 150508Z AMSUB 89GHZ
MICROWAVE IMAGE REVEALS A BROADENING CIRCULATION WITH DEEP
CONVECTION LIMITED TO THE SOUTHERN SEMICIRCLE. A PARTIAL 150124Z
SMAP MICROWAVE RADIOMETER PASS REVEALS THE MAXIMUM WINDS (64-65KTS)
RESIDE IN THE SOUTHERN REGION OF THE LLCC, WHILE 36-45KT WINDS
DOMINATE ELSEWHERE. THE INITIAL POSITION IS PLACED WITH MEDIUM
CONFIDENCE BASED ON MSI AND AMSUB IMAGERY. THE INITIAL INTENSITY OF
60 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON 150124Z SMAP
DATA INDICATING SLIGHTLY ABOVE PGTW AND KNES DVORAK INTENSITY
ESTIMATES WHILE MOST OTHER AUTOMATED ESTIMATES REMAIN TOO LOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: 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: 46 KTS AT 150348Z
   CIMSS ADT: 35 KTS AT 150300Z

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

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: THE NEARLY 800NM JOURNEY OF TC 02A (BIPARJOY)
IS RAPIDLY COMING TO A CLOSE. OVER THE NEXT 12 HOURS, 02A WILL
CONTINUE TO APPROACH THE PAKISTAN-INDIA BOARDER. DURING THIS TIME,
INCREASING LAND INTERACTION WILL COMBINE WITH ALREADY MODERATE
VERTICAL WIND SHEAR (VWS) AND DRY AIR ENTRAINMENT TO GRADUALLY
WEAKEN THE SYSTEM TO AROUND 55KTS. AFTER MAKING LANDFALL JUST AFTER
TAU 12, THE SYSTEM WILL BE PUSHED INLAND BY THE STR OVER SOUTHERN
INDIA AND THE BUILDING RIDGE OVER THE STRAIT OF HORMUZ. AS IS
USUALLY THE CASE, MAKING LANDFALL IS GAME OVER. THE SYSTEM WILL
RAPIDLY WEAKEN AND DETERIORATE THROUGH TAU 36, EVENTUALLY
DISSIPATING NEAR TAU 48.

MODEL DISCUSSION: WITH THE EXCEPTION OF NVGM TO THE NORTH,
NUMERICAL MODELS ARE IN GOOD AGREEMENT THAT 02A WILL MAKE LANDFALL
FOLLOWING TAU 12 AND PROCEED NORTHEAST INTO THE PAKISTAN-INDIA
BOARDER. FOR THIS REASON, THE JTWC TRACK FORECAST IS PLACED WITH
HIGH CONFIDENCE. RELIABLE MODEL INTENSITY GUIDANCE IS IN GOOD
AGREEMENT WITH EXCEPTION OF GFS AND COAMPS-TC. THESE TWO MEMBERS
CONTINUE TO UNREALISTICALLY INTENSIFY THE SYSTEM BEFORE LANDFALL
WHILE THE REMAINING GUIDANCE WEAKENS THE SYSTEM THROUGH THE
FORECAST PERIOD. BASED ON THE DETERIORATING ENVIRONMENT MENTIONED
ABOVE, LESS CREDENCE IS PLACED IN GFS AND COAMPS-TC, RESULTING IN
AN OVERALL HIGH CONFIDENCE IN THE JTWC INTENSITY FORECAST.

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