WDPS31 PGTW 100300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05P (CODY) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.1S 176.3E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 169 NM SOUTHWEST OF SUVA, FIJI
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A
FULLY-EXPOSED, WELL-DEFINED LOW-LEVEL CIRCULATION CENTER, WHICH
SUPPORTS THE INITIAL POSITION WITH HIGH CONFIDENCE, WITH DEEP
CONVECTION SHEARED ABOUT 30NM SOUTH. A 100131Z AMSR2 89GHZ
MICROWAVE IMAGE INDICATES EXTENSIVE DEEP CONVECTIVE BANDING OVER
THE EASTERN AND SOUTHERN SEMICIRCLES WRAPPING BROADLY AROUND THE
CENTER. ANIMATED WATER VAPOR IMAGERY AND UW-CIMSS FEATURE TRACK
WINDS CONTINUE TO SHOW AN UPPER-LEVEL TROUGH AND POSSIBLE CLOSED
LOW OVER THE SYSTEM, WHICH IS HINDERING DEVELOPMENT OF CORE
CONVECTION. THE INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH HIGH
CONFIDENCE AND IS HEDGED SLIGHTLY HIGHER THAN THE PGTW AND KNES
DVORAK ESTIMATES BASED ON THE CIMSS ADT ESTIMATE.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: THE SUBTROPICAL RIDGE (STR) POSITIONED
TO THE SOUTH IS NOW THE DOMINANT STEERING INFLUENCE. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   PHFO: T3.5 - 55 KTS
   CIMSS ADT: 47 KTS AT 092340Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 05P HAS SLOWED AND TURNED WEST-SOUTHWESTWARD 
UNDER THE DOMINANT STEERING INFLUENCE OF THE STR TO THE SOUTH. A 
SERIES OF SHORTWAVE TROUGHS WILL WEAKEN THE STR INDUCING A SLOW 
POLEWARD TRACK. NEAR TAU 48, AN APPROACHING MAJOR SHORTWAVE TROUGH 
WILL FURTHER WEAKEN THE STR, WHICH WILL LEAD TO A FASTER 
SOUTHEASTWARD TRACK ALONG THE SOUTHWESTERN PERIPHERY OF A STEERING 
RIDGE TO THE EAST. THE SYSTEM IS EXPECTED TO REMAIN WITHIN A COMPLEX 
UPPER-LEVEL ENVIRONMENT UNDER A BROAD UPPER-LEVEL TROUGH, HOWEVER, 
SLIGHT INTENSIFICATION IS ANTICIPATED DUE TO ROBUST POLEWARD
OUTFLOW WITH A PEAK INTENSITY OF 45-50 KNOTS. AFTER TAU 72, TC 05P
WILL GRADUALLY WEAKEN AS IT BECOMES FURTHER EMBEDDED WITHIN THE
UPPER-LEVEL TROUGH AND ENCOUNTERS STRONG VERTICAL WIND SHEAR (30-45
KNOTS) AND COOLER SST VALUES (24-25C). AFTER TAU 72, TC 05P IS
FORECASTED TO GRADUALLY TRANSITION INTO A SUBTROPICAL CYCLONE. 

MODEL DISCUSSION: THE NUMERICAL MODELS AND ENSEMBLE GUIDANCE (EPS
AND GEFS) SUPPORT THE JTWC FORECAST TRACK WITH MEDIUM CONFIDENCE
WITH SOME UNCERTAINTY IN THE EXACT TRACK DUE TO THE COMPLEX,
RAPIDLY-EVOLVING SYNOPTIC PATTERN. THERE IS ALSO UNCERTAINTY IN THE
JTWC INTENSITY FORECAST DUE TO THE PRESENCE OF THE UPPER-LEVEL
TROUGH OVER THE SYSTEM AND THE POTENTIAL FOR DRY AIR ENTRAINMENT,
WHICH IS EXPECTED TO LIMIT DEVELOPMENT. THE BULK OF THE RELIABLE
INTENSITY GUIDANCE SUPPORTS THE JTWC FORECAST WITH MEDIUM
CONFIDENCE. AFTER TAU 72, THE JTWC INTENSITY FORECAST IS SLIGHTLY
BELOW THE JTWC INTENSITY CONSENSUS DUE TO INCREASING VERTICAL WIND
SHEAR AND COOL SST VALUES (23-24C).  

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