WDPN31 PGTW 130300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (MEARI) WARNING NR 
008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 33.7N 137.3E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 153 NM SOUTHWEST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE LOW LEVEL
CIRCULATION (LLC) OF TS 09W IS NOW JUST PARTLY EXPOSED, AS
CONVECTION HAS BEGUN TO BUILD BACK OVER THE LLC, WITH THE MAIN
CONVECTION SHEARED SOUTH- TO SOUTHWESTWARD. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON THE MSI AND COMPOSITE RADAR
LOOPS. THE INITIAL INTENSITY OF 35KTS IS HEDGED SLIGHTLY HIGHER
THAN THE AGENCY AND MORE IN LINE WITH THE ADT DVORAK ESTIMATE.
ANALYSIS INDICATES VWS HAS DECREASED. THIS, PLUS THE STRONG
EQUATORWARD OUTFLOW AND WARM SST RESULT IN A MARGINALLY FAVORABLE
ENVIRONMENT.

INITIAL WIND RADII BASIS: PERSISTENCE.

CURRENT STEERING MECHANISM: NORTHWESTERN PERIPHERY OF THE LOW- TO
MID-LAYER REFLECTION OF THE SUBTROPICAL RIDGE (STR) TO THE EAST.


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   KNES: T2.0 - 30 KTS
   CIMSS ADT: 35 KTS AT 122340Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   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 MEARI WILL CONTINUE TO TRACK NORTHEASTWARD
ALONG THE NORTHWESTERN EDGE OF THE STEERING STR, DRAG ACROSS THE
SOUTHERN COAST OF HONSHU THROUGH TOKYO THEN EXIT BACK INTO THE
PACIFIC OCEAN SHORTLY AFTER TAU 12. THE MARGINALLY FAVORABLE
ENVIRONMENT, TEMPERED BY LAND INTERACTION, WILL ALLOW A SLIGHT
INTENSIFICATION TO A PEAK OF 40KTS AT TAUS 12 TO 24. AFTERWARD,
COOLING SST AND ENTRY INTO THE BAROCLINIC ZONE WILL GRADUALLY
WEAKEN THE CYCLONE. ALSO BY TAU 24, THE SYSTEM WILL BEGIN
EXTRA-TROPICAL TRANSITION AND BY TAU 36, WILL TRANSFORM INTO A
35-KT COLD CORE LOW. THERE IS A DISTINCT POSSIBILITY THAT TS MEARI
WILL DISSIPATE OR FALL BELOW JTWC WARNING CRITERIA AFTER ITS
PASSAGE OVER LAND. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY RIGHT AGREEMENT WITH
GRADUAL AND EVEN SPREAD TO A MERE 55NM BY TAU 36, LENDING HIGH
CONFIDENCE IN THE JTWC TRACK FORECAST. THERE IS, HOWEVER, LOW
CONFIDENCE IN THE INTENSITY FORECAST DUE TO THE POTENTIAL EARLY
DISSIPATION.

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