WDXS31 PGTW 071500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02S (AWO) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 7.1S 60.8E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 697 NM WEST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A RAGGED
AND ILL-DEFINED CIRCULATION, WITH WEAK CONVECTION DISPLACED TO THE
SOUTHWEST OF A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER
(LLCC). A 071143Z SSMIS 91GHZ MICROWAVE IMAGE REVEALED SHALLOW
BANDING FEATURES LAID OUT ACROSS THE NORTHERN HEMISPHERE OF THE
ROTATION, WITH A SMALL BUT WELL-DEFINED LLCC ON THE NORTHEASTERN
TIP OF A BAND OF NORTH-SOUTH ORIENTED DEEP CONVECTION. THE INITIAL
POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE MSI AND THE
MICROWAVE IMAGE NOTED ABOVE. THE INITIAL INTENSITY IS ASSESSED WITH
HIGH CONFIDENCE BASED ON THE SUBJECTIVE AND OBJECTIVE INTENSITY
ESTIMATES NOTED BELOW. ENVIRONMENTAL CONDITIONS ARE HIGHLY
UNFAVORABLE, WITH MODERATE TO HIGH EASTERLY SHEAR, RELATIVELY COOL
SSTS AND A MASSIVE REGION OF VERY DRY AIR LURKING JUST WEST OF THE
LLCC, WHICH IS ALREADY STARTING TO WRAP INTO THE SYSTEM FROM THE
NORTHWEST.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: NORTHERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED FAR TO THE SOUTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   FMEE: T2.5 - 35 KTS
   CIMSS SATCON: 39 KTS AT 070927Z
   CIMSS ADT: 34 KTS AT 071200Z
   CIMSS AIDT: 33 KTS AT 071100Z
   CIMSS D-MINT: 27 KTS AT 071144Z
   CIMSS D-PRINT: 32 KTS AT 071200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 20-25 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: WEAK POLEWARD
   OTHER FACTORS: SIGNIFICANT AMOUNT OF DRY MID-LEVEL AIR
ENTRENCHED ALL ALONG THE WESTERN FLANK OF THE SYSTEM. 

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE FORECAST HAS BEEN
TRUNCATED TO 24 HOURS. 
 
FORECAST DISCUSSION: DURING THE VERY SHORT DURATION OF THE
FORECAST, TS AWO IS FORECAST TO TRACK WEST-NORTHWESTWARD ALONG THE
NORTHERN SIDE OF THE STR SITUATED FAR TO THE SOUTH. THE SYSTEM HAD
A VERY SHORT WINDOW OF OPPORTUNITY TO DEVELOP, WHICH IS NOW RAPIDLY
CLOSING. SHEAR IS ALREADY ESTIMATED BY CIMSS TO BE RUNNING IN FROM
THE EAST AT 25 KNOTS. THIS IS BORN OUT BY THE CIMSS AMV DATA
SHOWING STRONG EASTERLY FLOW EXTENDING FAR UPSTREAM OF THE SYSTEM
ITSELF. AS MENTIONED ABOVE, A VERY LARGE MASS OF VERY DRY AIR LURKS TO 
THE WEST AND IS ALREADY STARTING TO INFILTRATE INTO THE SYSTEM, 
ESPECIALLY ACROSS THE NORTHERN HALF OF THE ROTATION. THE SITUATION 
WILL DETERIORATE FURTHER OVER THE NEXT 12 HOURS, WITH THE DRY AIR 
EXPECTED TO COMPLETELY ENGULF AND SMOTHER THE INNER CORE OF TS AWO, 
MARKING ITS DEMISE. THE SYSTEM WILL RAPIDLY WEAKEN UNDER THIS DRY AIR 
AND INCREASING SHEAR, ULTIMATELY DISSIPATING WITHIN THE NEXT 24 HOURS. 
THE REMNANT CIRCULATION IS LIKELY TO CONTINUE TRACKING TOWARDS THE 
NORTHWEST AND MAY TRACK CLOSE TO THE SEYCHELLES WITHIN THE NEXT 48 
HOURS, BUT WIND SPEEDS WILL BE MINIMAL BY THAT TIME. 

MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE ARE IN
GOOD AGREEMENT THROUGH THE SHORT FORECAST PERIOD, WITH LESS THAN
100NM SPREAD AT TAU 24. INTENSITY GUIDANCE IS ALSO IN TIGHT
AGREEMENT THROUGH THE FORECAST PERIOD, LENDING HIGH CONFIDENCE TO
BOTH THE JTWC TRACK AND INTENSITY FORECASTS. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: HIGH//
NNNN