WDPN32 PGTW 191500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 24W (RAGASA) WARNING NR 
005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.3N 130.1E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 536 NM EAST-NORTHEAST OF MANILA,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
STORM 24W (RAGASA) WITH A LARGE AREA OF DEEP CONVECTION OBSCURING
THE LOW-LEVEL CIRCULATION CENTER (LLCC). POLEWARD OUTFLOW APPEARS
TO BE IMPROVING, APPARENT BY CIRRUS FILAMENTS BEGINNING TO EXPAND
OUTWARD FROM THE SYSTEM IN THAT DIRECTION. A 191148Z GMI 37 GHZ
MICROWAVE IMAGE REVEALED THAT THE LOW-LEVELS ARE STILL A BIT
DISORGANIZED WITH NO DEFINED MICROWAVE EYE FORMED YET. THE 89 GHZ
VERSION OF THE SAME IMAGE SHOWS THAT THE CONVECTION IS STILL
DISPLACED TO THE SOUTHEAST OF THE LLCC, AND HAS NOT BECOME ENTIRELY
VERTICALLY STACKED. ENVIRONMENTAL ANALYSIS INDICATES THAT 24W IS IN
A HIGHLY FAVORABLE ENVIRONMENT CHARACTERIZED BY STRONG POLEWARD AND
EQUATORWARD OUTFLOW ALOFT, LOW (5-10 KTS) VERTICAL WIND SHEAR, AND
WARM (29-30 C) SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON THE AFOREMENTIONED GMI 
MICROWAVE IMAGES. THE INITIAL INTENSITY OF 45 KTS IS ASSESSED WITH 
MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK AND OBJECTIVE INTENSITY
ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A SUBTROPICAL
RIDGE TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 47 KTS AT 191130Z
   CIMSS AIDT: 38 KTS AT 191130Z
   CIMSS D-MINT: 37 KTS AT 191148Z
   CIMSS D-PRINT: 43 KTS AT 191130Z

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

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: 24W IS FORECAST TO TRACK RATHER SLOWLY
NORTHWESTWARD OVER THE NEXT 48 HOURS AS THE SUBTROPICAL RIDGE TO
THE NORTH CONTINUES TO BUILD. NEAR TAU 72, THE RIDGE WILL HAVE
BUILT IN AND WILL HAVE MORE INFLUENCE ON STEERING THE VORTEX. 24W
WILL THEN INCREASE TRACK SPEEDS AS IT PASSES THROUGH THE LUZON
STRAIT WITH A MORE WEST-NORTHWESTWARD TRAJECTORY. THIS MOTION WILL
THEN PERSIST THROUGH THE REMAINDER OF THE FORECAST PERIOD AS THE
SYSTEM APPROACHES THE SOUTHERN COAST OF CHINA. REGARDING INTENSITY,
24W IS FORECAST TO RAPIDLY INTENSIFY OVER THE NEXT 48 HOURS TO
AROUND 105 KTS. ENVIRONMENTAL CONDITIONS WILL BE NEARLY PERFECT
FOR RAPID DEVELOPMENT AS THE SYSTEM TAPS INTO AN IMPROVED POLEWARD
OUTFLOW CHANNEL OVER THE NEXT 24 HOURS. A PEAK INTENSITY OF AROUND
120 KTS IS FORECAST TO OCCUR NEAR TAU 72, NORTH OF LUZON. EASTERLY
VERTICAL WIND SHEAR IS EXPECTED TO INCREASE TO 15-20 KTS AT TAU 96
AND ONWARD, CAUSING 24 TO SLIGHTLY WEAKEN AS IT HEADS FOR THE
SOUTHERN COAST OF CHINA. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE CONTINUES TO BE IN
GOOD AGREEMENT WITH A 95 NM CROSS-TRACK SPREAD AT TAU 72 WHICH
OPENS UP TO 165 NM AT TAU 120. GFS HAS BECOME THE NORTHERNMOST
MEMBER THROUGH THE LUZON STRAIT WHILE ECMWF TRACKS THE SYSTEM
CLOSER TO NORTHERN LUZON. THE JTWC TRACK FORECAST IS PLACED CLOSE
TO THE MULTI-MODEL CONSENSUS, HEDGED SLIGHTLY CLOSER TO ECMWF, WITH
HIGH CONFIDENCE THROUGH TAU 72 AND MEDIUM CONFIDENCE THEREAFTER.
NEARLY ALL RAPID INTENSIFICATION (RI) AIDS ARE TRIGGERING THIS
MODEL RUN. MESOSCALE MODELS ARE IN GOOD AGREEMENT IN TERMS OF THE
PEAK INTENSITY OF 24W WITH HAFS-A, HWRF, AND COAMPS-TC ALL RANGING
FROM 115 TO 125 KTSAT TAU 72. GUIDANCE ALSO AGREES ON WEAKENING
AFTER TAU 72. OF NOTE, HWRF TRACKS THE SYSTEM FURTHER NORTH,
CLIPPING SOUTHERN TAIWAN, AND THEREFORE WEAKENS THE SYSTEM MUCH
MORE QUICKLY THAN HAFS-A OR COAMPS-TC. THE JTWC INTENSITY FORECAST
IS PLACED CLOSE TO THE MULTI-MODEL CONSENSUS THROUGH TAU 48, AND
THEN CLOSE TO HAFS-A FOR THE REMAINDER OF THE FORECAST PERIOD WITH
OVERALL LOW CONFIDENCE. 

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