WDPS32 PGTW 230900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 19P (RAE) WARNING NR 
003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.3S 178.8W
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 474 NM WEST OF PAGO PAGO
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP
CONVECTION OBSCURING THE LOW-LEVEL CIRCULATION CENTER (LLCC) OF
TROPICAL CYCLONE 19P. DRY AIR WRAPPING IN FROM THE SOUTHWEST
REVEALS THE TIGHT LOW-LEVEL CLOUD BANDING CIRCULATING INTO THE
OBSCURED CENTER. WATER VAPOR IMAGERY REVEALS STRONG RADIAL OUTFLOW
ASSOCIATED WITH A POINT SOURCE ALOFT AND HIGHLY FAVORABLE
UPPER-LEVEL DIVERGENCE. THE INITIAL POSITION WAS PLACED WITH HIGH
CONFIDENCE BASED ON A 230545 WSFM WMI COLOR-ENHANCED 37GHZ
MICROWAVE IMAGE HIGHLIGHTING THE DEEP CONVECTIVE BANDING WRAPPING
INTO CENTER. THE INITIAL INTENSITY WAS PLACED WITH MEDIUM
CONFIDENCE BASED ON THE AGENCY AND OBJECTIVE FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: A SUBTROPICAL RIDGE TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   APRF: T2.5 - 35 KTS
   CIMSS ADT: 57 KTS AT 230530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 19P WILL CONTINUE TO BE
DRIVEN SOUTHWARD ON THE PERIPHERY OF A SUBTROPICAL RIDGE TO THE
EAST. AFTER TAU 36, THE SYSTEM WILL CURVE SOUTHEASTWARD HAVING
CROSSED THE RIDGE AXIS. IN THE NEAR-TERM FORECAST, THE ENVIRONMENT
WILL BE FAVORABLE FOR INTENSIFICATION TO A PEAK OF 80KTS DUE TO LOW
VERTICAL WIND SHEAR, WARM SEA SURFACE TEMPERATURES, AND STRONG
DIVERGENCE ALOFT. BETWEEN TAU 48-72, TC 19P WILL BEGIN SUBTROPICAL
TRANSITION AS THE SYSTEM TRACKS OVER COOL SEA SURFACE TEMPERATURES
AND BEGIN TO INTERACT WITH THE JET TO THE SOUTH. THE SYSTEM WILL
WEAKEN AS THE SYSTEM UNDERGOES SUBTROPICAL TRANSITION AND BECOMES
FULLY SUBTROPICAL BY TAU 72.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN STRONG
AGREEMENT THAT THE SYSTEM WILL CURVE SOUTHEASTWARD ON THE WESTERN
PERIPHERY OF A SUBTROPICAL RIDGE. THE CROSS-TRACK SPREAD BY TAU 72
IS 165NM. THE JTWC INTENSITY GUIDANCE IS IN GOOD AGREEMENT THAT THE
SYSTEM WILL RAPIDLY INTENSIFY DURING THE FIRST 24 HOURS OF THE
FORECAST AS INDICATED BY SEVERAL RAPID INTENSIFICATION AIDS. THE
SPREAD BETWEEN PEAK INTENSITIES IS 10KTS BETWEEN 75KTS (HAFS-A) AND
90KTS (GFS). 

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