WDPN32 PGTW 181500 							
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 09S (NINE)     	
WARNING NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.4S 110.1E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 637 NM NORTH-NORTHWEST OF LEARMONTH, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A MOSTLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC), DISPLACED TO THE EAST OF AN AREA OF PERSISTENT DEEP CONVECTION DUE TO THE CONTINUED PRESSURE OF MODERATE EASTERLY SHEAR. AN 180906Z SSMIS 89GHZ MICROWAVE IMAGE REVEALED A SMALL AND EXPOSED LLCC POSITIONED TO THE EAST OF AN AREA OF ELONGATED (EAST-WEST) DEEP CONVECTION. EXTRAPOLATION OF THE MICROWAVE IMAGE, COMBINED WITH THE PARTIALLY VISIBLE LLCC IN THE EIR, PROVIDED HIGH CONFIDENCE TO THE INITIAL POSITION. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE, BASED ON T2.5 INTENSITY ESTIMATES FROM PGTW AND ABOM, AS WELL AS THE OBJECTIVE ESTIMATES NOTED BELOW. THE ENVIRONMENT CONTINUES TO BE MARGINAL AT BEST, WITH MODERATE EASTERLY SHEAR, LIMITED AND WEAK RADIAL OUTFLOW, DRY MID-LEVEL AIR ALONG THE EASTERN FLANK AND WARM SSTS. 

INITIAL WIND RADII BASIS: PERSISTENCE.				

CURRENT STEERING MECHANISM: NORTHWESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) OVER NORTHWESTERN AUSTRALIA. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   APRF: T2.5 - 35 KTS
   CIMSS ADT: 35 KTS AT 181200Z
   CIMSS AIDT: 33 KTS AT 181200Z
   CIMSS DPRINT: 39 KTS AT 181330Z
   CIMSS DMINT: 37 KTS AT 181027Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: WEAK RADIAL					

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: NO SIGNIFICANT CHANGES.			

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 09S (NINE) HAS TURNED TO THE WEST-SOUTHWEST OVER THE PAST SIX HOURS BASED ON THE BEST TRACK POSITIONS. A HOT-OFF-THE-PRESSES ASCAT PASS COMING IN AT THIS MOMENT INDICATES A CENTER NEAR 12.2S 109.7E OR JUST A BIT NORTHWEST OF THE 1200Z INITIAL POSITION. WE WILL GO BACK AND ADJUST THAT AFTER THE FACT. WITH THIS NEW DATA, IT APPEARS THE LLCC HAS TRACKED WESTWARD OVER THE PAST SIX HOURS, ALONG THE NORTHERN SIDE OF THE STR OVER NORTHWESTERN AUSTRALIA, AS ANALYZED BY THE ECMWF. THOUGH RECENT COMMUNICATIONS ISSUES AT JTWC HAVE RESULTED IN A LIMITED SET OF MODEL DATA FOR THIS FORECAST CYCLE, THERE IS NO MAJOR SHIFT IN THE SYNOPTIC SITUATION AND THIS FORECAST IS VERY SIMILAR TO THE LAST, EXCEPT FOR A SLOWER TRACK SPEED AFTER TAU 72 AND A GRADUAL TURN TOWARDS THE NORTHWEST BY THE END OF THE FORECAST PERIOD. IN TERMS OF INTENSITY, DUE TO THE EXTREMELY LIMITED GUIDANCE AVAILABLE, THERE IS NO CHANGE TO THE JTWC FORECAST. THE SYSTEM IS EXPECTED TO MAINTAIN ITS CURRENT INTENSITY FOR 24 TO 36 HOURS AND MAY IN FACT WEAKEN BELOW THE 35 KNOT THRESHOLD DURING THIS TIMEFRAME, AS MODERATE EASTERLY SHEAR AND DRY AIR PERSIST AND HINDER DEVELOPMENT. AFTER TAU 36, SHEAR CONDITIONS ARE EXPECTED TO IMPROVE, AND THE ATMOSPHERE WILL MOISTEN, ALLOWING THE SYSTEM TO SLOWLY INTENSIFY THROUGH THE REMAINDER OF THE FORECAST PERIOD.  

MODEL DISCUSSION: AS MENTIONED, DUE TO A COMMUNICATIONS OUTAGE, THERE IS VERY LIMITED MODEL GUIDANCE CURRENTLY AVAILABLE. HOWEVER, ANALYSIS OF THE SYNOPTIC PATTERN REVEALS NO SIGNIFICANT CHANGES FROM THE PREVIOUS FORECAST. HOWEVER, WHAT LIMITED GUIDANCE IS AVAILABLE (GFS, GEFS, INTERPOLATED ECMWF AND GALWEM) DOES HINT AT SOME POSSIBLE CHANGES, WITH THE GFS AND GEFS BOTH SLOWING THE SYSTEM DOWN AFTER TAU 48 AND TURNING IT EQUATORWARD WHILE THE OTHER MODELS KEEP UP A STEADY WESTWARD TRACK. THE JTWC FORECAST IS HEDGED BACK A BIT, TRENDING MORE TOWARDS THE GFS SOLUTION. CONFIDENCE IS LOW HOWEVER DUE TO THE LACK OF GUIDANCE. INTENSITY GUIDANCE IS EVEN MORE SCARCE, WITH NO MESOSCALE MODELS AVAILABLE. THE OVERALL PATTERN HAS NOT CHANGED, WITH AN EXPECTATION OF DECREASED SHEAR AND IMPROVED OUTFLOW, SO THE FORECAST REMAINS THE SAME.  

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