WDPS31 PGTW 211500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 16P (SIXTEEN) WARNING 
NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.8S 163.0E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 190 NM WEST-NORTHWEST OF NOUMEA, NEW
CALEDONIA
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 25 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE 16P WITH A WELL-DEFINED, EXPOSED LOW-LEVEL CIRCULATION
CENTER (LLCC) THAT IS TRACKING PARALLEL TO THE COAST OF NEW
CALEDONIA. DEEP CONVECTION REMAINS DISPLACED TO THE WEST OF THE
LLCC. A 211006Z METOP-B ASCAT IMAGE REVEALED A COMPACT WIND FIELD
WITH THE STRONGEST WINDS (40 KTS) WITHIN A SMALL PATCH IN THE
NORTHEASTERN QUADRANT. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE EXPOSED LLCC IN ANIMATED EIR IMAGERY. THE
INITIAL INTENSITY AND WIND RADII ARE BOTH ASSESSED WITH HIGH
CONFIDENCE BASED PRIMARILY ON THE AFOREMENTIONED ASCAT IMAGE.
AGENCY DVORAK FIXES OF T2.5-3.0 FURTHER SUPPORT THE INITIAL
INTENSITY ESTIMATE OF 40 KTS. ENVIRONMENTAL ANALYSIS INDICATES THAT
16P IS IN A MARGINALLY FAVORABLE ENVIRONMENT CHARACTERIZED BY
MODERATE POLEWARD OUTFLOW ALOFT, LOW (10-15 KTS) NORTHEASTERLY
VERTICAL WIND SHEAR, SLIGHT DRY AIR ENTRAINMENT, AND WARM (27-28 C)
SEA SURFACE TEMPERATURES.

INITIAL WIND RADII BASIS: 211006Z METOP-B ASCAT SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED NEAR FIJI. 


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   PHFO: T3.0 - 45 KTS
   CIMSS ADT: 34 KTS AT 211200Z
   CIMSS AIDT: 35 KTS AT 211200Z
   CIMSS D-MINT: 36 KTS AT 210725Z
   CIMSS D-PRINT: 30 KTS AT 211200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE POLEWARD
   OTHER FACTORS: SLIGHT DRY AIR ENTRAINMENT FROM THE NORTHWEST

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE FORECAST HAS BEEN TRUNCATED TO 48
HOURS. OTHERWISE, THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST.

FORECAST DISCUSSION: TC 16P IS FORECAST TO CONTINUE TRACKING
SOUTHEASTWARD ALONG THE SOUTHWESTERN PERIPHERY OF THE STR THROUGH
TAU 24. AFTER TAU 24, THE TRAJECTORY IS FORECAST TO BECOME MORE
EASTWARD AS THE SYSTEM ROUNDS THE RIDGE AND BEGINS TO TRACK ALONG
THE SOUTHERN PERIPHERY OF THE RIDGE. EVEN THOUGH THE WIND FIELD OF
16P IS EXPECTED TO REMAIN QUITE COMPACT, THE EXTENT OF GALE-FORCE
WINDS WILL LIKELY SKIRT THE SOUTHERN COASTS OF NEW CALEDONIA,
POTENTIALLY AFFECTING AREAS NEAR NOUMEA AS 16P PASSES BY. REGARDING
INTENSITY, 16P IS FORECAST TO MAINTAIN INTENSITY THROUGH TAU 12
UNDER SIMILAR ENVIRONMENTAL CONDITIONS. AFTER TAU 12, INCREASING
DRY AIR ENTRAINMENT AND VERTICAL WIND SHEAR WILL GRADUALLY WEAKEN
THE SYSTEM. DISSIPATION IS FORECAST TO OCCUR AROUND TAU 48, AS THE
SYSTEM BECOMES ENGULFED BY DRY AIR FROM THE WEST. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE REMAINS IN VERY
GOOD AGREEMENT THROUGHOUT THE FORECAST PERIOD WITH NO SIGNIFICANT
OUTLIERS PRESENT. CROSS-TRACK AND ALONG-TRACK SPREAD AT TAU 48 IS
AROUND 80 NM AND 90 NM RESPECTIVELY. THE JTWC TRACK FORECAST IS
PLACED CLOSE TO THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE.
INTENSITY GUIDANCE GENERALLY AGREES ON A GRADUAL WEAKENING TREND
AFTER TAU 12. THE JTWC INTENSITY FORECAST IS ALSO PLACED NEAR THE
CONSENSUS WITH HIGH CONFIDENCE.

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