WDPN31 PGTW 221500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (TRAMI)
WARNING NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.6N 125.9E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 285 NM EAST OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 21 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A DEFINED
EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC), WITH A LARGE CLUSTER OF
INTENSE DEEP CONVECTION PERSISTING OVER THE SOUTHWESTERN QUADRANT. A
221159Z GMI 89GHZ COLOR COMPOSITE MICROWAVE IMAGE REVEALS TIGHTLY-
CURVED SHALLOW BANDING WRAPPING INTO A DEFINED LLCC, WHICH SUPPORTS
THE INITIAL POSITION WITH HIGH CONFIDENCE, AND CURVED DEEP CONVECTIVE
BANDING OVER THE WESTERN SEMICIRCLE. A 220951Z RCM-3 SAR IMAGE ALSO
SUPPORTS THE INITIAL POSITION SHOWING AN ELONGATED CENTER WITH
UNREALISTICALLY HIGH WINDS OF 65-70 KNOTS OVER THE SOUTHERN
SEMICIRCLE. UPPER-LEVEL ANALYSIS INDICATES A MARGINALLY FAVORABLE
ENVIRONMENT WITH LOW TO MODERATE NORTHEASTERLY VERTICAL WIND SHEAR
OFFSET BY MODERATE WESTWARD VENTING, WHICH IS SUSTAINING DEEP
CONVECTION AND CURVED BANDING OVER THE WESTERN SEMICIRCLE. THE INITIAL
INTENSITY OF 40 KTS IS HEDGED SLIGHTLY HIGHER THAN THE PGTW, RCTP AND
KNES SUBJECTIVE DVORAK ESTIMATES BASED ON THE WELL-ORGANIZED LOW-LEVEL
STRUCTURE EVIDENT IN THE GMI IMAGE AS WELL AS CIMSS DMINT AND DPRINT
OBJECTIVE ESTIMATES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK

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

AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T2.5 - 35 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   CIMSS ADT: 32 KTS AT 221130Z
   CIMSS DPRINT: 38 KTS AT 221230Z
   CIMSS DMINT: 44 KTS AT 221200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE WESTWARD

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 STORM (TS) 22W IS FORECAST TO TRACK
WEST-NORTHWESTWARD THROUGH TAU 24 ALONG THE SOUTHWESTERN PERIPHERY
OF THE STR, TOWARD A BREAK IN THE STR PRODUCED BY A MIDLATITUDE
SHORTWAVE TROUGH DIGGING INTO THE EAST CHINA SEA. AFTER TAU 24, THE
STR WILL REBUILD TO THE NORTH TURNING THE SYSTEM ONTO A MORE
WESTWARD TRAJECTORY. THE SYSTEM WILL INTENSIFY SLIGHTLY BEFORE
LANDFALL UNDER THE MARGINALLY FAVORABLE CONDITIONS. LANDFALL OVER
EASTERN LUZON WILL OCCUR NEAR TAU 24, WITH SIGNIFICANT WEAKENING
COMMENCING. AFTER TAU 24, TS 22W WILL WEAKEN AND DECOUPLE WHILE
CROSSING THE RUGGED TERRAIN OF LUZON, WITH A LIKELY LEESIDE JUMP.
THIS WILL RESULT IN AN APPARENT DIP IN THE FORECAST TRACK AS A NEW
PRESSURE CENTER FORMS AND STRENGTHENS OFF THE WEST COAST OF LUZON
NEAR TAU 48. AFTER TAU 48, THE SYSTEM WILL RESUME A WESTWARD TRACK
UNDER THE STR TO THE NORTH WITH STEADY INTENSIFICATION TO ABOUT 60
KNOTS BY TAU 72.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE REMAINS IN GOOD
AGREEMENT THROUGH THE FORECAST PERIOD, WITH AN 80NM TO 90NM CROSS-
TRACK SPREAD FROM TAU 48 TO TAU 96. AFTER TAU 96, THE GUIDANCE
DIVERGES SLIGHTLY WITH INCREASING UNCERTAINTY ASSOCIATED WITH A WEAK
NORTHEAST SURGE EVENT. PROBABILISTIC GUIDANCE INDICATES A WIDER SPREAD
OF SOLUTIONS FROM NORTHERN HAINAN ISLAND TO ABOUT 15N LATITUDE
SUGGESTING A LIKELY LANDFALL OVER CENTRAL VIETNAM JUST AFTER TAU 120.
RELIABLE INTENSITY GUIDANCE SHOWS A PEAK INTENSITY AT TAU 72 RANGING
FROM 55 KNOTS (HAFS-A) TO AS HIGH AS 78 KNOTS (HWRF).

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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