WDIO31 PGTW 140900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02A (BIPARJOY) WARNING 
NR 033//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.5N 66.3E
   INITIAL INTENSITY: 85 KTS
   GEOGRAPHIC REFERENCE: 202 NM SOUTH OF KARACHI, PAKISTAN
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD 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 DRY AIR ENTRAINMENT IN THE
NORTHEAST QUADRANT. IN ADDITION, THERE ARE SPIRAL BANDS OF DEEP
CONVECTION WRAPPING INTO AN ASSESSED LOW LEVEL CIRCULATION CENTER
(LLCC). ANALYSIS OF THE 140153Z SSMIS 91 GHZ IMAGE REVEALS A
MICROWAVE EYE FEATURE WITH THE DEEPEST CONVECTION TO THE WEST AND
SOUTH 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 SOUTHWEST OF THE
LOW-LEVELS AS THE SYSTEM HAS A TILT TO ITS STRUCTURE AS A RESULT OF
THE UPPER-LEVEL WIND SHEAR FROM THE EAST. IN ADDITION, TC 02A
APPEARS TO BE IN A QUASI-STATIONARY POSTURE OVER THE PAST 18 HOURS
WITH A SLIGHT HINT OF FINALLY MAKING THE TRACK TO THE NORTHEAST AS
PREDICTED OVER THE PAST SEVERAL WARNINGS. 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). MOREOVER, AS A RESULT OF THE
QUASI-STATIONARY BEHAVIOR, THERE IS UPWELLING TO THE SOUTHEAST OF
THE LLCC WHICH IS COOLING THE SURFACE AIR NEAR THE CORE. 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 85
KNOTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED OFF A 140127Z
SENTINEL-1A SAR PASS REVEALING A SWATH OF 80-85 KNOT WINDS TO THE
WEST OF THE LLCC. THE SUBJECTIVE AND AUTOMATED DVORAKS ARE IN
DISAGREEMENT AND PRODUCING VALUES LOWER THAN THE SAR DATA.

INITIAL WIND RADII BASIS: 140127Z SENTINEL-1A SAR DATA 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   KNES: T4.5 - 77 KTS
   DEMS: T4.5 - 77 KTS
   CIMSS ADT: 53 KTS AT 140630Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 25-30 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE WESTWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT AND UPWELLING

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

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 TC BIPARJOY MADE A TURN NORTHEASTWARD AS THE SYSTEM ROUNDS
THE STR AXIS. BY TAU 12, THE SYSTEM WILL DECREASE IN INTENSITY TO
70 KNOTS AS A RESULT OF MORE DRY AIR ENTRAINMENT FROM THE NORTHEAST
AND THE EFFECTS OF THE PREVIOUSLY STATED UPWELLING. THROUGH TAU 24,
TC 02A WILL CONTINUE TO DECREASE IN INTENSITY TO 65 KNOTS DUE TO
LAND INTERACTION BEFORE MAKING LANDFALL NEAR THE INDIA-PAKISTAN
BORDER. THROUGH TAUS 36 AND 48, 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 NORTHEASTWARD WHILE
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: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM//
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