WDPN32 PGTW 182100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (TEN) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.8N 113.2E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 106 NM SOUTH-SOUTHWEST OF HONG KONG
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 11 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
COMPACT AREA OF DISORGANIZED PERSISTENT CONVECTION. THE INITIAL
POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON EXTRAPOLATION
FROM A 181413Z ASCAT-C PASS WITH GOOD COVERAGE OF THE LOW LEVEL
CIRCULATION CENTER (LLCC), AS WELL AS RADAR FIXES. DESPITE BEING
GENERALLY CHARACTERIZED BY 30 KNOT BARBS IN THE EARLIER ASCAT, THE
INTENSITY WAS SET AT 35 KNOTS WHICH IS SLIGHTLY HIGHER THAN AGENCY
FIXES, BASED ON IMPROVING BANDING STRUCTURES IN THE RADAR LOOP, AND
ASSUMING SLIGHT INTENSIFICATION HAS OCCURRED SINCE THE ASCAT
OVERPASS TIME. THE COMPACT NATURE OF 10W ALSO SUGGESTS THAT DVORAK
ESTIMATES MAY BE SLIGHTLY UNDER-REPRESENTATIVE.

INITIAL WIND RADII BASIS: MEASURED USING SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: WEAK SUB-TROPICAL RIDGING TO THE
NORTHEAST OVER SOUTHERN CHINA

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   KNES: T2.0 - 30 KTS
   CIMSS ADT: 31 KTS AT 181750Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: PROXIMITY TO LAND MAY LIMIT INTENSIFICATION

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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: TS 10W IS FORECAST TO CONTINUE STEADILY
TRACKING WEST-NORTHWESTWARD TO WESTWARD THROUGH TAU 72 UNDER THE
STEERING INFLUENCE OF THE WEAK STR TO THE NORTH. AFTER TAU 72, THE
SYSTEM WILL SLOW UNDER COMPETING STEERING INFLUENCES AND TURN
GRADUALLY BACK TO THE SOUTHEAST UNDER THE STEERING INFLUENCE OF THE
LOW-LEVEL WESTERLY FLOW THAT IS EXPECTED TO BUILD IN TO THE SOUTH
THROUGH THE COMING DAYS. IN GENERAL, THE NUMERICAL MODEL GUIDANCE
SUPPORTS THE FORECAST TRACK, HOWEVER, THERE IS A LARGE DEGREE OF
SPREAD DUE TO THE COMPLEX, EVOLVING SYNOPTIC STEERING ENVIRONMENT.
TS 10W SHOULD INTENSIFY TO A PEAK OF 55 KNOTS AT TAU 36 JUST PRIOR
TO LANDFALL WITH STEADY WEAKENING AS THE SYSTEM TRACKS OVER LAND.
TD 10W WILL LIKELY RE-INTENSIFY NEAR TAU 120 OR SHORTLY AFTER
REEMERGING BACK OVER WATER. THE INTENSITY IS HIGHLY DEPENDENT ON
THE DEGREE THAT THE ACTUAL TRACK REMAINS OVERS LAND, AND COULD BE
HIGHER IF TS 10W REMAINS NEAR THE COAST.

MODEL DISCUSSION: THERE IS LIMITED MODEL GUIDANCE AVAILABLE AT THIS
TIME, WITH A LARGE SPREAD AMONG THESE SOLUTIONS GIVEN THE COMPLEX
SYNOPTIC STEERING ENVIRONMENT MADE EVEN MORE UNCERTAIN DUE TO THE
PRESENCE OF 09W AND A POTENTIAL FUTURE AREA OF DEVELOPMENT IN ITS
WAKE. THIS UNCERTAINTY IS EVIDENT IN THE LARGE CIRCULAR CONE OF
POTENTIAL 34 KNOT WINDS. ALTHOUGH RAPID INTENSIFICATION IS NOT
EXPECTED GIVEN THE SHORT TIME TO LANDFALL AND CURRENT POOR
ORGANIZATION, IT REMAINS A POSSIBILITY GIVEN OTHERWISE FAVORABLE
FACTORS.  

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