WDPN31 PGTW 130900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 09W (MEARI) WARNING 
NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 34.7N 138.3E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 78 NM WEST-SOUTHWEST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A PARTIALLY
EXPOSED, DETERIORATING LOW-LEVEL CIRCULATION (LLC) WITH LIMITED
DEEP CONVECTION SHEARED OVER THE SOUTHERN SEMICIRCLE OF THE LLC.
ANIMATED RADAR IMAGERY SHOWS A RAPIDLY DETERIORATING LOW-LEVEL
CIRCULATION CENTER WITH CONVECTIVE BANDING OVER WATER TO THE SOUTH.
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON MSI
AND JMA RADAR FIXES. NEAR 130550Z, THE CENTER PASSED DIRECTLY OVER
OMAEZAKI (34.6N 138.2E) WHICH REPORTED MAXIMUM WINDS OF 22 KNOTS
AND MINIMUM SLP NEAR 998.3 MB. AS THE SYSTEM PASSED OVER SURUGA
BAY, THE LOW-LEVEL STRUCTURE BECAME MORE ILL-DEFINED AND
FRAGMENTED. THE MAXIMUM SURFACE WINDS THUS FAR OBSERVED ALONG THE
COAST WERE AT IROZAKI ON THE SOUTHERN TIP OF THE IZU PENINSULA,
WHICH PEAKED AT ABOUT 32 KNOTS AT 130700Z. OTHERWISE, SURFACE WIND
OBSERVATIONS HAVE BEEN UNIMPRESSIVE. THE INITIAL INTENSITY IS 
ASSESSED AT 30 KNOTS WITH HIGH CONFIDENCE BASED ON THE OBSERVATIONAL 
DATA AND THE DVORAK ESTIMATES. ENVIRONMENTAL CONDITIONS ARE
MARGINAL AS THE SYSTEM BEGINS TO INTERACT WITH A BROAD UPPER-LEVEL 
TROUGH OVER CENTRAL JAPAN WITH STRONG DIFFLUENCE ALOFT SUSTAINING 
CONVECTION OVER WATER. ADDITIONALLY, VERTICAL WIND SHEAR HAS 
INCREASED TO HIGH (25 KNOTS) LEVELS.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) 
ENTRENCHED TO THE SOUTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   KNES: T2.0 - 30 KTS
   CIMSS SATCON: 40 KTS AT 130419Z
   CIMSS ADT: 35 KTS AT 130540Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD
   OTHER FACTORS: INTERACTION WITH LAND

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

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

FORECAST DISCUSSION: AS MENTIONED EARLIER, THE SYSTEM HAS BEGUN
EXTRA-TROPICAL TRANSITION (ETT) AND IS FORECAST TO ACCELERATE
NORTHEASTWARD WITHIN THE MIDLATITUDE SOUTHWESTERLIES ALONG THE
NORTHWESTERN FLANK OF THE STR. ADDITIONAL WEAKENING WILL LIKELY OCCUR
OVER THE NEXT SIX HOURS AS THE SYSTEM TRACKS OVERLAND, HOWEVER, TD
09W WILL GRADUALLY RE-INTENSIFY TO 35-40 KNOTS BY TAU 24 AS IT
COMPLETES ETT WITHIN THE STRONG MIDLATITUDE WESTERLY FLOW AND GAINS
FRONTAL CHARACTERISTICS. 

MODEL DISCUSSION: DETERMINISTIC AND PROBABILISTIC MODEL GUIDANCE IS
IN TIGHT AGREEMENT WITH A 10NM SPREAD IN SOLUTIONS NEAR TOKYO
DIVERGING TO A 50NM SPREAD IN SOLUTIONS AT TAU 24 LENDING HIGH
CONFIDENCE TO THE JTWC FORECAST TRACK. THERE IS MEDIUM CONFIDENCE
IN THE JTWC INTENSITY FORECAST DUE TO THE DETRIMENTAL INTERACTION
WITH LAND AND UNCERTAINTY IN THE TIMING OF THE REINTENSIFICATION
PHASE AFTER TAU 06. 

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