WDIO31 PGTW 100300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02A (BIPARJOY) 
WARNING NR 016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.7N 67.4E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 487 NM SOUTH OF KARACHI, PAKISTAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THAT TC
02A HAS UNDERGONE ANOTHER CYCLE OF INTENSIFICATION BUT HAS ALREADY
STARTED TO SHOW SIGNS OF BEING UNABLE TO SUSTAIN THE TREND. EIR
SHOWS THAT THE NASCENT EYE FEATURE SEEN SIX HOURS AGO HAS ALREADY
DISAPPEARED AND THE CENTRAL DENSE OVERCAST (CDO) IS WARMING AND
BECOMING MORE RAGGED. A 092059Z AMSR2 36GHZ IMAGE SHOWED A WEAK
LOW-LEVEL MICROWAVE EYE AND WITH A DISORGANIZED CIRCULATION CENTER
ABOVE THAT, WITH THE ROTATION DISPLACED SIGNIFICANTLY TO THE WEST
DUE TO THE EFFECTS OF PERSISTENT MODERATE EASTERLY SHEAR. THE
SYSTEM DOES CONTINUE TO PUSH BACK AGAINST THE SHEAR FOR THE TIME
BEING BUT APPEARS TO BE WAGING A LOSING BATTLE AT THIS POINT. DUE
TO THE LACK OF RECENT MICROWAVE IMAGERY, THE INITIAL POSITION IS
ASSESSED WITH LOW CONFIDENCE AS THE LLCC REMAINS OBSCURED BY THE
RAGGED CDO. THE INITIAL INTENSITY IS INCREASED TO 70 KNOTS,
SLIGHTLY LOWER THAN THE SUBJECTIVE AGENCY FIXES, BUT IN LINE WITH
THE SATCON ESTIMATE AND AN AMSR2 WINDSPEED ESTIMATE OF 72 KNOTS.
THE SYSTEM IS MOVING SLOWLY NORTHWARD OVERALL, BUT RECENT IMAGERY
SUGGESTS IT IS WOBBLING AS IT MOVES NORTHBOUND, AS THE STEERING
INFLUENCE IS RELATIVELY WEAK AT PRESENT. ANALYSIS REVEALS A
FAVORABLE ENVIRONMENT OVERALL, WITH THE MAIN INHIBITING FACTOR
BEING THE PERSISTENT MODERATE SHEAR.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A NORTH-SOUTH
ORIENTED RIDGE OVER WESTERN INDIA. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   KNES: T4.5 - 77 KTS
   DEMS: T4.5 - 77 KTS
   CIMSS SATCON: 69 KTS AT 092126Z
   CIMSS ADT: 74 KTS AT 100000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 31-32 CELSIUS
   OUTFLOW: STRONG WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   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: TC 02A IS FORECAST TO CONTINUE TO TRACK
GENERALLY NORTHWARD ALONG THE WESTERN SIDE OF THE NORTH-SOUTH
ORIENTED RIDGE OVER WESTERN INDIA. SOME WOBBLING EAST AND WEST OF A
MEAN NORTH TRACK IS EXPECTED DUE TO FLUCTUATIONS IN THE ORIENTATION
AND STRENGTH OF THE RIDGE, BUT THE OVERALL MOVEMENT WILL BE
POLEWARD THROUGH THE ENTIRE FORECAST PERIOD. THE FORECAST REMAINS
HIGHLY UNCERTAIN, ESPECIALLY AFTER TAU 72, WHEN MAJOR DIFFERENCES
BEGIN TO EMERGE IN THE GLOBAL MODELS IN REFERENCE TO THE STEERING
PATTERN AND THE SUBSEQUENT TRACK OF TC 02A CONTINUES TO FLUCTUATE
WILDLY BACK AND FORTH AS IT APPROACHES THE SOUTHERN COAST OF
PAKISTAN. BOTH THE GFS AND ECWMF IN GENERAL AGREE THAT THE RIDGE TO
THE EAST WILL SLIDE SOUTH INTO THE INTERIOR OF INDIA, AND THEY BOTH
AGREE THAT A RIDGE IS FORECAST TO BUILD OVER SOUTHERN IRAN AT THE
SAME TIME. HOWEVER, THEY DIVERGE ON THE STRENGTH OF THE RIDGE TO
THE WEST OVER IRAN AND JUST HOW FAR IT BUILDS IN OVER PAKISTAN,
WITH THE ECMWF INDICATING A MUCH STRONGER RIDGE TO THE NORTH THAN
THE GFS. THUS THE GFS HAS NOW SHIFTED THE TRACK BACK TOWARDS THE
WEST, POINTING RIGHT AT KARACHI WHILE THE ECMWF STUBBORNLY
CONTINUES TRACKING THE SYSTEM TOWARDS GUJARAT PENINSULA. HOWEVER,
THE INTERMEDIATE RUN OF THE ECMWF NOW HAS SHIFTED BACK OVER TO THE
WEST, EVEN FURTHER WEST THAN THE GFS. ALL THAT TO SAY THAT
LATE-STAGE FORECAST IS EXTREMELY UNCERTAIN. THE INTENSITY FORECAST
CONTINUES TO BE CHALLENGING AS WELL WITH THE CONSTANT CYCLING AND
INABILITY OF THE SYSTEM TO ESTABLISH A PERSISTENT CONVECTIVE CORE
COMPLICATING THE FORECAST CONSIDERABLY. OVERALL, SHEAR IS EXPECTED
TO BE RELATIVELY MODERATE FOR THE NEXT 24 TO 36 HOURS WHICH SHOULD
ALLOW FOR SOME ADDITIONAL INTENSIFICATION. HOWEVER, AFTER TAU 36
SHEAR IS EXPECTED TO PICK UP ONCE AGAIN, AND AFTER A 200MB
ANTICYCLONE ESTABLISHES ITSELF TO THE NORTH AROUND TAU 48,
CONVERGENT EASTERLY FLOW WILL SERVE TO SQUASH ANY FURTHER HOPE FOR
THE SYSTEM, WHICH WILL WEAKEN STEADILY THROUGH THE REMAINDER OF THE
FORECAST. 

MODEL DISCUSSION: AS BRIEFLY DISCUSSED ABOVE, TRACK GUIDANCE IS IN
A FAIR AMOUNT OF DISARRAY, PARTICULARLY AFTER TAU 72. THROUGH THE
EARLY PORTIONS OF THE FORECAST, THE MODEL TRACKERS GRADUAL SPREAD
TO A 150NM WIDE ENVELOPE WITH THE NAVGEM AND GALWEM ON THE LEFT
SIDE AND UKMET ON THE RIGHT. AFTER TAU 72 THE WHEELS COME OFF AND
SPREAD RAPIDLY INCREASES TO NEARLY 500NM WITH THE NAVGEM, HWRF AND
GFS ENSEMBLE MARKING THE LEFT EDGE AND UKMET AND THE SECOND
INTERPOLATION OF THE ECMWF ON THE RIGHT EDGE. AS MENTIONED, THE
INTERMEDIATE RUN OF ECMWF HOWEVER HAS FLIPPED OVER TO THE WEST AND
IS NOW ALIGNING MORE WITH THE NAVGEM AND GALWEM SOLUTIONS.
MEANWHILE THE GFS AND COAMPS-TC TRACKERS ARE ROUGHLY DOWN THE
MIDDLE, BUT GENERALLY CONSISTENT WITH THE PREVIOUS RUN.
ADDITIONALLY, THE ENSEMBLE MEAN TRACKERS CONTINUE TO EXHIBIT A VERY
WIDE SPREAD RANGING FROM A LANDFALL ON THE GUJARAT ALL THE WAY TO A
TRACK TOWARDS THE MOUTH OF THE GULF OF OMAN. HENCE, CONFIDENCE IS
EXTREMELY LOW IN THE EXTENDED TAUS. INTENSITY GUIDANCE IS ALSO A
BIT MIXED, WITH THE MESOSCALE MODELS ARE PERSISTENT IN TRYING TO
INTENSIFY THE SYSTEM UP TO 100 KNOTS, WHILE THE SHIPS GUIDANCE IS
EQUALLY INSISTENT THE SYSTEM WILL LINGER AROUND ITS CURRENT
INTENSITY FOR ABOUT 48 HOURS BEFORE RAPIDLY WEAKENING. THE JTWC
FORECAST CALLS FOR SOME INTENSIFICATION, BUT LESS THAN THE
AGGRESSIVE MESOSCALE MODELS, FOLLOWED BY STEADY WEAKENING, WITH
MEDIUM CONFIDENCE. 

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