WDPS32 PGTW 022100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 09P (NINE) WARNING NR 
009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.1S 157.2E
   INITIAL INTENSITY: 20 KTS
   GEOGRAPHIC REFERENCE: 620 NM NORTHWEST OF NOUMEA, NEW CALEDONIA
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 8 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A WEAK,
POORLY-DEFINED LOW-LEVEL CIRCULATION (LLC) WITH A SMALL AREA
CONVECTION ON THE NORTHERN PERIPHERY. A 021735Z SSMIS 91GHZ IMAGE 
HINTS TO A WEAKLY-DEFINED LLC WITH NO HINT OF CONVECTIVE BANDING.
THE INITIAL POSITION AND INITIAL INTENSITY OF 20 KNOTS ARE BASED OFF
THE PGTW POSITION FIX AND CURRENT INTENSITY ESTIMATE WHICH WAS TOO 
WEAK FOR A T1.0 ASSESSMENT. TC 09P IS CURRENTLY IN A MARGINAL 
ENVIRONMENT WITH POLEWARD OUTFLOW RESTRICTED DUE TO AN UPPER-LEVEL 
LOW AND TROUGH TO THE SOUTH AND SOUTHEAST. ADDITIONALLY, THERE IS A 
SIGNIFICANT MASS OF DRY AIR OVER THE SOUTHERN PERIPHERY OF THE 
SYSTEM.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL RIDGE TO THE NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   CIMSS SATCON: 35 KTS AT 021514Z
   CIMSS ADT: 25 KTS AT 021740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: WEAK EQUATORWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 09P IS FORECAST TO TRACK EAST-SOUTHEASTWARD
UNDER THE INFLUENCE OF THE NEAR EQUATORIAL RIDGE UNTIL TAU
48, AT WHICH POINT THE SYSTEM WILL TURN SOUTHEASTWARD AS THE RIDGE 
REORIENTS. A MARGINAL ENVIRONMENT CONSISTING OF DRY AIR ENTRAINMENT, 
WEAK OUTFLOW ALOFT, AND MODERATE VERTICAL WIND SHEAR WILL LIMIT
INTENSIFICATION IN THE EARLY PORTION OF THE FORECAST. SOMETIME
AFTER TAU 36, THE SYSTEM WILL BEGIN TO INTENSIFY AS POLEWARD
OUTFLOW IMPROVES AND THE CORE ENVIRONMENT MOISTENS. THE SYSTEM IS
FORECAST TO REACH 50 KTS BY TAU 120.

MODEL DISCUSSION: NUMERICAL MODELS ARE CURRENTLY IN SPLIT AGREEMENT
IN REGARDS TO FORECAST TRACK WITH NVGM, EGRR, AND UEMN PASSING
SOUTH OF THE LOYALTY ISLANDS AND EC AND GFS PASSING TO THE NORTH
WITH GFS JUST SOUTH OF PORT VILA. THIS RESULTS IN A 250 NM
CROSS-TRACK SPREAD AT TAU 48 AND CONTINUES TO EXPAND AFTERWARDS. 
INTENSITY GUIDANCE IS IN AGREEMENT AS FAR AS INDICATING SOME TYPE OF 
INTENSITIFCATION HAPPENING BY TAU 36, BUT THE RATE AND MAGNITUDE 
VARY WITH GFS HOVERING AROUND 25 KTS UNTIL TAU 36 AND HWRF JUMPING 
TO 35 KTS BY TAU 12. OVERALL, THERE IS LOW CONFIDENCE IN THE 
FORECAST BEYOND TAU 36.

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