WDPN31 PGTW 230300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 19W (KAJIKI) WARNING NR 
003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.5N 116.6E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 318 NM SOUTH-SOUTHEAST OF HONG KONG
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP
CONVECTION TILTED WESTWARD DUE TO 15-20KT NORTHEASTERLY VERTICAL
WIND SHEAR. THE LOW-LEVEL CLOUD BANDS TO THE EAST OF THE LOW-LEVEL
CIRCULATION CENTER (LLCC) ARE PARTIALLY EXPOSED THROUGH CIRRUS
FILAMENTS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY
HIGHLIGHTS THE COOLING CLOUD TOPS HINTING AT THE DEVELOPMENT AND
INTENSIFICATION OF TROPICAL STORM (TS) 19W OVER THE LAST SIX HOURS. 
THE INITIAL POSITION IS PLACED WITH LOW CONFIDENCE BASED ON THE 
PARTIAL OBSCURATION OF THE LLCC UNDER THE EXPANSIVE CIRRUS SHIELD 
ALOFT. THE INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH LOW 
CONFIDENCE BASED ON THE AGENCY AND OBJECTIVE FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: A SUBTROPICAL RIDGE TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.0 - 30 KTS
   CIMSS SATCON: 44 KTS AT 222215Z
   CIMSS ADT: 33 KTS AT 222020Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TS 19W WILL CONTINUE TO TRACK WESTWARD FOR THE
REMAINDER OF THE FORECAST PERIOD. THE SYSTEM WILL BE STEERED BY AN
ELONGATED SUBTROPICAL RIDGE TO THE NORTH. AT TAU 24, TS 19W WILL
BRIEFLY PASS OVER HAINAN AND MAKE FINAL LANDFALL IN VIETNAM BETWEEN
TAU 48-72. INTENSIFICATION WILL BE FUELED IN THE FIRST 36 HOURS BY
LOW VERTICAL WIND SHEAR AND SOUTHWESTWARD UPPER-LEVEL DIFFLUENCE.
SEA SURFACE TEMPERATURES WILL BE HIGH AND OCEAN HEAT CONTENT (OHC)
WILL BE FAVORABLE FOR SIGNIFICANT INTENSIFICATION IN THE NEAR TERM.
ONCE THE STORM ENTERS THE GULF OF TONKIN, UPWELLING IN THE
SHALLOWER WATERS WILL LIMIT INTENSIFICATION PRIOR TO LANDFALL. TS
19W WILL DISSIPATE AFTER LANDFALL BY TAU 72.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN STRONG
AGREEMENT THAT TS 19W WILL TRACK WESTWARD FOR THE REMAINDER OF THE
FORECAST PERIOD. THE CROSS-TRACK SPREAD AT TAU 72 IS 50NM. THERE IS
MORE UNCERTAINTY IN THE INTENSITY GUIDANCE. THERE IS A SPREAD OF
PEAK INTENSITIES BETWEEN 45-110KTS IN THE JTWC INTENSITY GUIDANCE.
THERE ARE SEVERAL RAPID INTENSIFICATION AIDS (RI) INDICATING RI
WITHIN THE FIRST 24 HOURS, BUT THE OCEAN HEAT CONTENT WEST OF 110E
IS NOT AS HIGH, AND HAFS-A PARENT MODEL INDICATES UPWELLING OF COOL
WATER AS THE SYSTEM PASSES INTO THE GULF OF TONKIN. THUS, THE
OCEAN-COUPLED MODELS PEAK BETWEEN 60-65KTS AT TAU 36. THE JTWC
INTENSITY FORECAST CONFIDENCE IS LOW BASED ON THE VAGUE ENVIRONMENTAL 
SUPPORT FOR RI.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: LOW//
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