WDIO31 PGTW 142100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02A (BIPARJOY) 
WARNING NR 035//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.2N 66.7E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 157 NM SOUTH OF KARACHI, PAKISTAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
SHEARED AND ASYMMETRIC REPRESENTATION, WITH MINIMAL CONVECTION TO
THE NORTH AND A BROAD SWATH OF ENHANCED CONVECTION HOLDING FAST
ALONG THE SOUTHERN PERIPHERY. A 141640Z AMSU-B 89GHZ AND 157GHZ
IMAGE SHOWED A RELATIVELY NAKED LOW LEVEL CIRCULATION TO THE NORTH
WITH VERY WEAK BANDING FEATURES, ALONG WITH A PATCH OF INTENSE
CONVECTION TO THE SOUTHWEST OF THE LLCC. THE SYSTEM MEANDERED
TOWARDS THE NORTH OVER THE PAST 6 TO 12 HOURS THROUGH A RELATIVELY
WEAK STEERING ENVIRONMENT. THOUGH THE LLCC REMAINS OBSCURED, THE
TIMELY MICROWAVE PASS PROVIDED HIGH CONFIDENCE TO THE INITIAL
POSITION. THE INITIAL INTENSITY IS ASSESSED AT 65 KNOTS WITH HIGH
CONFIDENCE, IN LINE WITH THE MAJORITY OF THE SUBJECTIVE AND
OBJECTIVE FIX ESTIMATES AND SUPPORTED BY AN EARLIER 161316Z SMAP
PASS SHOWING 68 KNOTS 1-MIN WINDS IN THE SOUTHEAST QUADRANT. HIGHER
WINDS ARE LIKELY PRESENT ALONG THE SOUTHERN PERIPHERY, PARTICULARLY
WITHIN THE AREAS OF ENHANCED AND PERSISTENT CONVECTIVE ACTIVITY,
WHILE WINDS ALONG THE NORTHERN SIDE ARE A BIT LOWER. THE
ENVIRONMENT CONTINUES TO DETERIORATE, WITH UNFAVORABLE MODERATE TO
HIGH EAST-NORTHEAST SHEAR NOW BEING JOINED BY CONVERGENCE ALOFT AND
DRY MID-LEVEL AIR.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WEAK STEERING PATTERN DEFINED BY A
SUBTROPICAL RIDGE (STR) OVER INDIA A SECOND STR OVER THE NORTHEAST
ARABIAN PENINSULA EXTENDING EASTWARD OVER SOUTHERN PAKISTAN. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   KNES: T4.0 - 65 KTS
   DEMS: T4.0 - 65 KTS
   CIMSS SATCON: 63 KTS AT 141513Z
   CIMSS ADT: 37 KTS AT 141800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 25-30 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: DRY MID-LEVEL AIR MASS TO THE NORTHEAST. 

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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 02A HAS SLOWED DOWN ONCE MORE AND AFTER
MAKING A JOG TO THE WEST YESTERDAY, HAS RESUMED A GENERAL NORTHWARD
MOTION. TRACK SPEEDS ARE AROUND FOUR KNOTS AS THE OVERALL STEERING
PATTERN REMAINS RELATIVELY WEAK AS THE SYSTEM LIES BETWEEN A STR
CENTERED OVER INDIA AND A WEAKER RIDGE OVER THE STRAIT OF HORMUZ
WHICH EXTENDS EASTWARD ACROSS SOUTHERN PAKISTAN. MODELS SUGGEST THE
EASTERN RIDGE WILL WEAKEN STEADILY OVER THE NEXT 48 HOURS, WHILE
THE RIDGE TO THE NORTH WILL REMAIN IN PLACE AND BUILD SLIGHTLY. IN
RESPONSE TO THE CHANGES IN THE RIDGE PATTERN, TC 02A IS FORECAST TO
KICK OUT OF TOWARDS THE NORTHEAST OVER THE NEXT 12 HOURS AS THE
RIDGE TO THE EAST RECEDES. LANDFALL IS NOW EXPECTED TO OCCUR AROUND
TAU 24, IN THE VICINITY OF THE PAKISTAN-INDIA BORDER REGION. NO
SIGNIFICANT CHANGE IS ANTICIPATED IN THE INTENSITY THROUGH
LANDFALL. WHILE THE SYSTEM CONTINUES TO STRUGGLE AGAINST THE
UNFAVORABLE ENVIRONMENTAL CONDITIONS, IT WILL TAKE TIME FOR THE
WIND FIELD TO SPIN DOWN. BURSTS OF CONVECTION, ESPECIALLY ALONG THE
SOUTHERN PERIPHERY, ARE STILL EXPECTED AND IN WHICH SLIGHTLY HIGHER
WINDSPEEDS CAN BE EXPECTED. ONCE ASHORE THE SYSTEM WILL RAPIDLY
WEAKEN AND DISSIPATE NO LATER THAN TAU 48 OVER WESTERN INDIA. 

MODEL DISCUSSION: TRACK GUIDANCE IS IN GOOD AGREEMENT WITH A VERY
TIGHT MODEL SPREAD THROUGH LANDFALL, EXPANDING MODESTLY THEREAFTER.
THE ENVELOPE EXTENDS FROM THE PAKISTAN-INDIA BORDER TO THE GULF OF
KUTCH AND THE JTWC FORECAST TRACK LIES IN THE MIDDLE OF THE
TIGHTEST GROUPING WITH HIGH CONFIDENCE. INTENSITY GUIDANCE IS ALSO
IN GOOD AGREEMENT ON A STAGNANT INTENSITY TREND THROUGH TAU 12
FOLLOWED BY SLOW WEAKENING TO LANDFALL AND THEN A SHARP WEAKENING
TO DISSIPATION BY TAU 48. 

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