WDPN32 PGTW 212100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 24W (RAGASA) WARNING NR 
014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.1N 124.1E
   INITIAL INTENSITY: 145 KTS
   GEOGRAPHIC REFERENCE: 588 NM EAST-SOUTHEAST OF HONG KONG
   MOVEMENT PAST 6 HOURS: WESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 46 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
SUPER TYPHOON (STY) 24W IS CURRENTLY UNDERGOING AN EYEWALL 
REPLACEMENT CYCLE (ERC), WITH A PRONOUNCED WOBBLE IN THE TRACK MOTION 
OVER THE PAST SIX HOURS. HOWEVER, THE ERC HAS HAD NO SIGNIFICANT 
IMPACT ON THE INTENSITY. AFTER A BRIEF PERIOD OF WEAKENING AND A 
DEVELOPING MOAT FEATURE, ANIMATED ENHANCED INFRARED (EIR) SATELLITE 
IMAGERY DEPICTS STRENGTHENING CORE CONVECTION WITH A SYMMETRIC, 
FAIRLY UNIFORM RING OF EYEWALL CLOUD TOP TEMPERATURES NEAR -80C, WARM 
EYE TEMPERATURES (16-17C) AND EXTENSIVE SPIRAL BANDING OVER ALL 
QUADRANTS. RECENT HIGH-RESOLUTION MICROWAVE IMAGERY HAS BEEN SPARSE 
MAKING IT MORE DIFFICULT TO ASSESS THE ERC. ENVIRONMENTAL CONDITIONS 
REMAIN HIGHLY FAVORABLE, WITH STRONG RADIAL OUTFLOW AND LOW VERTICAL 
WIND SHEAR. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED 
ON THE EYE FEATURE IN EIR SATELLITE IMAGERY. THE INITIAL INTENSITY OF 
145 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON AGENCY CURRENT 
INTENSITY ESTIMATES RANGING FROM 7.0-7.5 (140-155 KNOTS) AND THE 
CIMSS D-MINT AND D-PRINT ESTIMATES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
ENTRENCHED TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.0 - 140 KTS 
   RJTD: T7.0 - 140 KTS 
   RCTP: T7.5 - 155 KTS
   KNES: T7.0 - 140 KTS 
   DEMS: T7.0 - 140 KTS 
   CIMSS SATCON: 147 KTS AT 211731Z
   CIMSS ADT: 137 KTS AT 211730Z
   CIMSS AIDT: 135 KTS AT 211730Z
   CIMSS D-MINT: 148 KTS AT 211731Z
   CIMSS D-PRINT: 145 KTS AT 211830Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 0-5 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: STY 24W WILL TRACK WESTWARD THROUGH THE FORECAST 
PERIOD ALONG THE SOUTHERN PERIPHERY OF THE STR. HOWEVER, A 
MIDLATITUDE SHORTWAVE TROUGH EMBEDDED WITHIN ZONAL WESTERLIES IS
FORECAST TO BRIEFLY WEAKEN THE STR NEAR TAU 48, WHICH MAY PRODUCE A
SHORT-TERM WEST-NORTHWESTWARD TRACK MOTION AS THE SYSTEM TRACKS
NEAR THE LEIZHOU PENINSULA. AFTER THIS TROUGH PROPAGATES EASTWARD,
THE STR WILL QUICKLY REBUILD OVER CHINA DRIVING THE SYSTEM INTO
NORTHERN VIETNAM. STY 24W WILL MAINTAIN STY INTENSITY THROUGH TAU
36, WITH STEADY WEAKENING AFTER TAU 36 DUE TO UPWELLING COOLER
WATER AND FRICTIONAL EFFECTS. AFTER TAU 48, THE SYSTEM WILL WEAKEN
MORE RAPIDLY AS IT SKIRTS THE SOUTHERN COAST OF CHINA. AFTER
LANDFALL NEAR TAU 96 OVER VIETNAM, THE SYSTEM WILL RAPIDLY WEAKEN
AS IT TRACKS INLAND.       

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, NUMERICAL MODEL
GUIDANCE REMAINS IN GOOD AGREEMENT THROUGH THE FORECAST PERIOD, WITH 
AN 85-90NM CROSS-TRACK SPREAD FROM TAU 72 TO TAU 96. THE 211200Z GEFS 
AND EPS ENSEMBLES SUPPORTS THE JTWC FORECAST TRACK WITH MEDIUM 
CONFIDENCE AND INDICATE A HIGH PROBABILITY OF THE TRACK PASSING NORTH 
OF HAINAN ISLAND. RELIABLE INETNSITY GUIDANCE SUPPORTS THE JTWC 
INTENSITY FORECAST WITH MEDIUM CONFIDENCE.  

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
NNNN