WDIO31 PGTW 071500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02A (BIPARJOY) WARNING 
NR 006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.6N 66.4E
   INITIAL INTENSITY: 85 KTS
   GEOGRAPHIC REFERENCE: 597 NM SOUTHEAST OF MASIRAH ISLAND
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
AS THE SUN BEGINS TO SET OVER THE ARABIAN SEA, ANIMATED
MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP FLARING CORE
CONVECTION FULLY OBSCURING THE LLCC BENEATH AS WELL AS BANDING
FEATURES THROUGHOUT THE SOUTHERN AND WESTERN SEMICIRCLES. A RECENT
SUITE OF SSMIS AND AMSR2 MICROWAVE IMAGES, SPECIFICALLY THE 071226Z
AND 070858Z PASSES RESPECTIVELY REVEALS A SIGNIFICANT DISCONNECT
BETWEEN ULCC AND LLCC. PERSISTENT MODERATE VERTICAL WINDS SHEAR IS
TILTING THE SYSTEM WESTWARD AND SABOTAGING CONTINUED EFFORTS TO
CONSOLIDATE AND RAPIDLY INTENSIFY. A 070607Z SCATTEROMERTY PASS
REVEALS AN ASYMMETRIC WIND FIELD THAT IS HEAVILY FAVORING THE
SOUTHERN SEMICIRCLE. THE INITIAL POSITION IS PLACED WITH MEDIUM
CONFIDENCE BASED ON MSI, SSMIS AND AMSR2 IMAGERY. THE INITIAL
INTENSITY OF 85 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A
LACK OF SIGNIFICANT CONVECTIVE IMPROVEMENT THOUGH PERIODIC FLARING
IS STILL HAPPENING, WHICH COUPLED WITH LACK LUSTER DVORAK INTENSITY
ESTIMATES AND CIMSS AUTOMATED INTENSITY ESTIMATES, LEAVES A RANGE
OF 65-90KTS IN THE GUIDANCE.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL RIDGE (NER) TO THE
SOUTH AND STR TO THE EAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   KNES: T4.0 - 65 KTS
   CIMSS ADT: 67 KTS AT 070900Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 20-25 KTS
   SST: 31-32 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD
   OTHER FACTORS: DRY AIRMASS TO THE NORTH 

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 WINDOW FOR TC 02A (BIPARJOY) TO
SIGNIFICANTLY INTENSIFY IS CLOSING RAPIDLY. AS MENTIONED ABOVE,
RECENT MICROWAVE IMAGERY INDICATES PERSISTENT EASTERLY SHEAR IS
HAMPERING ANY SIGNIFICANT INTENSIFICATION. WITH THAT BEING SAID,
02A IS FORECAST TO TRACK GENERALLY NORTH-NORTHWESTWARD THROUGH THE
FORECAST PERIOD UNDER THE STEERING INFLUENCE OF A NER TO THE SOUTH
AND STR TO THE EAST. AS THE BLOCKING RIDGE TO THE NORTHWEST IS
BROKEN DOWN THROUGH TAU 24, WARM SEA SURFACE TEMPERATURES AND
MODERATE OUTFLOW ALOFT WILL PROVIDE A SMALL WINDOW FOR 02A TO
STRENGTHEN TO A PEAK INTENSITY NEAR 95KTS. THIS INTENSIFICATION IS
CONTINGENT ON WHETHER THE SYSTEM CAN CONSOLIDATE AND MAINTAIN
CONVECTIVE COVER AND PREVENT OR COUNTERACT FURTHER TILTING. AFTER
TAU 48 HOWEVER, AS THE SYSTEM PROGRESSES FURTHER INTO THE ARABIAN
SEA, THE PARTY WILL BE OVER, AS VERTICAL WIND SHEAR (VWS) AND DRY
AIR ENTRAINMENT GRADUALLY ERODE THE CIRCULATION. BY TAU 120, 02A
WILL BE FLANKED ON ALL SIDES BY A SEA OF DRY AIR, VWS WILL CONTINUE
TO CLIMB AND THE CIRCULATION WILL CONTINUE TO WEAKEN AS IT TRACKS
POLEWARD BEYOND THE FORECAST PERIOD.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN FAIR AGREEMENT WITH A
PERSISTENT SPREADING IN OUTPUT THROUGH THE FORECAST PERIOD. THIS
COUPLED WITH MODERATE RUN TO RUN VARIABILITY AND THE RESULT IS
OVERALL MEDIUM FORECAST TRACK CONFIDENCE. RELIABLE MODEL INTENSITY
GUIDANCE IS IN POOR AGREEMENT WITH HWRF AND GFS IMMEDIATELY
WEAKENING THE SYSTEM WHILE COAMPS-TC CONTINUES THE INTENSIFICATION
TREND AND THE REMAINING MEMBERS ARE DOWN THE MIDDLE. FOR THIS
REASON THE JTWC INTENSITY FORECAST IS PLACED WITH OVERALL LOW
CONFIDENCE.

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