WDIO31 PGTW 131500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02A (BIPARJOY) WARNING 
NR 030//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.3N 66.4E
   INITIAL INTENSITY: 90 KTS
   GEOGRAPHIC REFERENCE: 213 NM SOUTH OF KARACHI, PAKISTAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 34 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICT AN
ASYMMETRICAL SYSTEM THAT IS BATTLING PRESSURE IN THE NORTHEAST
QUADRANT. IN ADDITION, THERE ARE SPIRAL BANDS OF DEEP CONVECTION
WRAPPING INTO AN ASSESSED LOW LEVEL CIRCULATION CENTER (LLCC).
ANALYSIS OF A PARTIAL 131055Z SSMIS 91 GHZ IMAGE REVEALS THE
REMNANTS OF A MICROWAVE EYE. THIS FEATURE WAS SHORT-LIVED AND WAS
PRESENT BETWEEN THE PAST TWO WARNING CYCLES. THERE IS THE
POSSIBILITY THE MAXIMUM INTENSITY OF TC BIPARJOY INCREASED FOR A
SHORT WHILE DURING THIS EVENT AS STATED IN THE 130300Z PROGNOSTIC
REASONING. IN ADDITION, THE DEEPEST CONVECTION IS NOW LOCATED
PRIMARILY IN THE SOUTHWEST QUADRANT OF THE LLCC. COMPARISON BETWEEN
THE 91 GHZ AND THE 37 GHZ IMAGES FROM THE ABOVEMENTIONED SSMIS PASS
INDICATES THE UPPER-LEVELS ARE DISPLACED SLIGHTLY TO THE WEST ON
THE LOW-LEVELS AS THE SYSTEM HAS A TILT TO ITS STRUCTURE AS A
RESULT OF THE UPPER-LEVEL WIND SHEAR FROM THE EAST. TC BIPARJOY IS
IN A MARGINALLY FAVORABLE ENVIRONMENT FOR FURTHER TROPICAL
ACTIVITY. THESE CONDITIONS ARE CHARACTERIZED BY MODERATE WESTWARD
OUTFLOW ALOFT, A STRONG 850 MB VORTICITY SIGNATURE, VERY WARM
(29-30 C) SEA SURFACE TEMPERATURES (SST), OFFSET BY UNFAVORABLE
(25-30 KTS) VERTICAL WIND SHEAR (VWS). THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON MULTI-AGENCY FIXES, ALONG
WITH THE AFOREMENTIONED MSI AND EXTRAPOLATION FROM THE SSMIS
IMAGERY. THE INITIAL INTENSITY OF 90 KNOTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED OFF A BLEND OF SUBJECTIVE AND AUTOMATED DVORAKS.
THERE WAS A SHARP INCREASE IN THE AUTOMATED DVORAK ESTIMATES AS A
RESULT OF THE MICROWAVE EYE FEATURE, BUT THOSE ESTIMATES ARE NOW
WANING AS THE MICROWAVE EYE IS NOW OPENING UP.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) LOCATED TO THE
EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   KNES: T5.0 - 90 KTS
   DEMS: T4.5 - 77 KTS
   CIMSS SATCON: 76 KTS AT 130922Z
   CIMSS ADT: 82 KTS AT 131230Z

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

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 02A (BIPARJOY) CONTINUES TO BATTLE ITS
ENVIRONMENT AS IT RIDES THE WESTERN EDGE OF THE STR TO THE EAST. IT
APPEARS THE TRACK SPEED HAS SLOWED A BIT AS THE SYSTEM IS ABOUT TO
MAKE ITS TURN AROUND THE STR AXIS. THROUGH TAU 12, THE SYSTEM WILL
MAINTAIN ITS INTENSITY OF 90 KNOTS AS IT BEGINS TO MAKE THE TURN
NORTHWARD, ROUNDING THE STR AXIS. THROUGH TAUS 24 AND 36, TC 02A
WILL BE ON A NORTHEASTWARD TRAJECTORY AND WILL STEADILY WEAKEN TO
70 KNOTS DURING LANDFALL NEAR THE INDIA-PAKISTAN BORDER DUE TO LAND
INTERACTION. THROUGH TAUS 72 AND 96, TC 02A WILL DISSIPATE INLAND
OVER NORTHERN INDIA.

MODEL DISCUSSION: THE DETERMINISTIC AND ENSEMBLE MODELS ARE ALL IN
TIGHT AGREEMENT THAT TC BIPARJOY WILL TRACK NORTHWARD THROUGH TAU
12, THEN MAKE THE TURN NORTHEASTWARD AFTERWARDS RIDING THE
NORTHWESTERN PERIPHERY OF THE STR TO THE EAST. NAVGEM IS THE
OUTLIER SHOWING AN UNLIKELY SCENARIO OF THE SYSTEM HEADING DUE
NORTH-NORTHEAST THROUGHOUT THE FORECAST PERIOD. DUE TO THIS
SPORADIC BEHAVIOR, THE JTWC FORECAST TRACK IS SET TO THE RIGHT OF
CONSENSUS WITH HIGH CONFIDENCE. THE JTWC INTENSITY CONSENSUS
MEMBERS ALL AGREE WITH A DECAYING TREND THROUGH AFTER TAU 12 AS THE
SYSTEM TRANSITS CLOSER TO LAND. THE JTWC INTENSITY FORECAST IS SET
WITH MEDIUM CONFIDENCE THROUGHOUT THE FORECAST PERIOD.

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