WDPS33 PGTW 110300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 12P (TWELVE)     
WARNING NR 011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.2S 174.2E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 248 NM WEST-SOUTHWEST OF SUVA, FIJI
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 19 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
AS DEPICTED IN ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND
ENHANCED INFRARED SATELLITE IMAGERY, TROPICAL CYCLONE (TC) 12P
DEVELOPED A PERSISTENT CENTRAL DENSE OVERCAST, WHICH ALLOWED THE
LOW-LEVEL CIRCULATION CENTER (LLCC) TO ALIGN VERTICALLY WITH THE
UPPER-LEVEL CIRCULATION CENTER (ULCC). ANIMATED WATER VAPOR IMAGERY
REVEALED IMPROVING OUTFLOW OVER THE NORTHERN SEMICIRCLE, WHICH,
ALONG WITH DECREASING VERTICAL WIND SHEAR VALUES, ALLOWED TC 12P TO
STRENGTHEN BRIEFLY. AS A RESULT OF THE IMPROVED CONVECTIVE
STRUCTURE, DVORAK ESTIMATES INCREASED TO T2.5 TO T3.0 (35 TO 45
KNOTS). A 102110Z ASCAT-B BULLSEYE IMAGE PROVIDES FURTHER EVIDENCE
SUPPORTING THE DECISION TO REGENERATE TC 12P. FIRST, THE LLCC
CLEARLY SHIFTED UNDER THE CORE CONVECTION, ALBEIT FOR A SHORT
PERIOD OF TIME. SECOND, THE 25 KM PRODUCT SHOWED NUMEROUS 30-35
KNOT WINDS WITH SOME ISOLATED WINDS IN THE 35-40 KNOT RANGE. 
THEREFORE, THE INITIAL INTENSITY IS ASSESSED AT 35 KNOTS WITH HIGH
CONFIDENCE. THERE IS HIGH CONFIDENCE IN THE INITIAL POSITION BASED
ON THE ASCAT AND VISIBLE IMAGERY. RECENT MSI SINCE ABOUT 102230Z, 
INDICATES THE LLCC IS DECOUPLING FROM THE ULCC AND STALLING, WITH A 
QUASI-STATIONARY TRACK MOTION. RECENT EIR IMAGERY SHOWS THE CORE 
CONVECTION DIMINISHING AND BECOMING MORE ASYMMETRIC AS IT SHEARS TO 
THE EAST.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: WEAK STEERING ENVIRONMENT WITH THE NEAR-
EQUATORIAL RIDGE (NER) POSITIONED TO THE NORTH AND EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   PHFO: T2.5 - 35 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS PROGNOSTIC REASONING MESSAGE SETS 
AND REESTABLISHES THE ORIGINAL FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TC 12P IS FORECAST TO TRACK SLOWLY EASTWARD TO
NORTHEASTWARD OVER THE NEXT 12 HOURS, WITH THE INTENSITY REMAINING
NEAR 35 KNOTS. AFTER TAU 12, THE SYSTEM WILL DISSIPATE AS IT TRACKS
SLOWLY NORTHWARD DUE TO INCREASING VERTICAL WIND SHEAR (30-35 KNOTS) 
AND DRY AIR ENTRAINMENT.  

MODEL DISCUSSION: IN GENERAL, NUMERICAL MODEL GUIDANCE INDICATES A
SLOW EASTWARD TRACK WITH A NORTHWARD TURN THEN NORTHWESTWARD TO
WESTWARD SHARP TURN. THERE ARE, HOWEVER, SIGNIFICANT DIFFERENCES IN
THE TIMING OF THE NORTHWESTWARD TO WESTWARD TURN. ECMWF SHARPLY
TURNS THE SYSTEM WITHIN THE NEXT 24 HOURS WHILE GFS SHOWS A BROADER
TURN SKIRTING THE WESTERN COAST OF VITI LEVU NEAR TAU 48. SEVERAL
MODELS TRACK THE SYSTEM SOUTH OF VITI LEVU BEFORE TURNING THE
SYSTEM NORTHWARD. BASED ON THE LARGE SPREAD, THERE IS LOW CONFIDENCE 
IN THE EXACT TRACK ESPECIALLY CONSIDERING THE CURRENT DECOUPLING. THE 
HAFS-A AND COAMPS-TC (GFS) FORECASTS SUPPORT THE WEAKENING TREND WITH 
MINOR DIFFERENCES IN THE TIMING OF DISSIPATION.         

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