WDPN32 PGTW 192100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 24W (RAGASA) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.2N 130.0E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 529 NM EAST-NORTHEAST OF MANILA,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 26 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
STORM (TS) 24W (RAGASA) WITH A CONTINUED AREA OF DEEP CONVECTION
LOCATED IN CLOSE PROXIMITY TO THE LOW-LEVEL CIRCULATION CENTER
(LLCC). THE SURFACE CIRCULATION HAS BEEN COMPLETELY OBSCURED OVER
THE LAST FEW HOURS; HOWEVER, FRAGMENTED LOW-LEVEL CONVECTIVE LINES
HAVE BEEN OBSERVED WRAPPING INTO THE NORTHWESTERN QUADRANT. ALOFT,
MODERATE EQUATORWARD OUTFLOW HAS CONTINUED INTO THE SOUTHERN
SEMICIRCLE, WHILE VISIBLE STRIATIONS HAVE BEGUN DEVELOPING AROUND
THE NORTHERN FACE OF THE PRIMARY CONVECTIVE STRUCTURE. THE
ENVIRONMENT REMAINS HIGHLY FAVORABLE, WITH LOW VERTICAL WIND SHEAR
(10-15 KTS), WARM SEA SURFACE TEMPERATURES (29-30 C), AND A
SUPPORTIVE UPPER-LEVEL EQUATORWARD OUTFLOW CHANNEL. THE INITIAL
POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A 191644Z 37 GHZ
AMSR-2 IMAGE. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON 191644Z AMSR-2 WINDSPEED DATA.

INITIAL WIND RADII BASIS: PERSISTENCE

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T3.5 - 55 KTS
   CIMSS SATCON: 55 KTS AT 191830Z
   CIMSS ADT: 59 KTS AT 191910Z
   CIMSS AIDT: 50 KTS AT 191830Z
   CIMSS D-MINT: 56 KTS AT 191718Z
   CIMSS D-PRINT: 54 KTS AT 191910Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TS 24W IS FORECASTED TO TRACK TO THE NORTHWEST
THROUGH TAU 48, ALONG THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL
RIDGE (STR) LOCATED DIRECTLY TO THE NORTH AND NORTHEAST. AFTER TAU
48, THE ELONGATED STR WILL BEGIN DRIVING THE SYSTEM MORE WESTWARD.
BETWEEN TAU 48 AND TAU 120, TS RAGASA WILL BEGIN A
WEST-NORTHWESTWARD TRACK UNTIL THE END OF THE FORECAST PERIOD,
ALONG THE SAME SOUTHERN FLANK OF A WEAKENED WESTWARD EXTENSION OF
THE STR. AS TS 24W APPROACHES THE LUZON STRAIT, TRACK SPEEDS WILL
BEGIN INCREASING AS A COMPETING EQUATORIAL RIDGE TO THE SOUTHWEST
BEGINS RETREATING WESTWARD OVER MALAYSIA. WITH REGARD TO
INTENSITY, TS RAGASA IS EXPECTED TO RAPIDLY INTENSIFY TO 120 KTS BY
TAU 72. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO CONTINUE AS HIGHLY
FAVORABLE, WITH AN ADDITIONAL SUPPORTIVE POLEWARD OUTFLOW CHANNEL
UNTIL JUST AFTER TAU 72. MAXIMUM INTENSITIES ARE FORECASTED AT 120
KTS CLOSE TO TAU 72 AS THE TS PROGRESSES THROUGH THE LUZON STRAIT.
AFTER TAU 72, VWS IS EXPECTED TO INCREASE TO 15-20 KTS AT THE SAME
TIME DRY AIR BEGINS WRAPPING INTO THE SYSTEM AND TS RAGASA TRACKS
TOWARD SOUTHERN COASTAL CHINA, WITH A WEAKENING TREND EXPECTED FROM
TAU 72 TO TAU 120. 

MODEL DISCUSSION: NUMERICAL MODEL PREDICTION TRACK GUIDANCE IS IN
GOOD AGREEMENT, WITH A 130 NM CROSS-TRACK SPREAD AT TAU 72. AFTER
TAU 72, THE CROSS-TRACK SPREAD INCREASES TO 190 NM, WITH A FEW JTWC
CONSENSUS MEMBERS KEEPING THE SYSTEM JUST NORTH OF HAINAN. THE JTWC
TRACK FORECAST IS ALIGNED CLOSELY WITH THE MULTI-MODEL CONSENSUS,
LENDING HIGH CONFIDENCE TO THE INITIAL 72 HR TRACK FORECAST, AND
MEDIUM CONFIDENCE BETWEEN TAU 72 AND TAU 120. WITH REGARD TO
INTENSITY, THE JTWC INTENSITY FORECAST IS ASSESSED WITH MEDIUM
CONFIDENCE AND HEDGED SLIGHTLY HIGHER THAN THE MULTI-MODEL
CONSENSUS DUE TO AN EXPECTED PHASE OF RAPID INTENSIFICATION THROUGH
TAU 72. AFTER TAU 72, THE JTWC INTENSITY FORECAST ALIGNS CLOSELY
WITH THE MULTI-MODEL INTENSITY CONSENSUS, AS AN INCREASINGLY
UNFAVORABLE ENVIRONMENT IS FORECASTED INTO TAU 120, LENDING LOW
CONFIDENCE TO THE INTENSITY FORECAST BETWEEN TAU 72 AND TAU 120.

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