WDPN32 PGTW 130900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07W (SON-TINH) WARNING NR 
005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 36.0N 146.9E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 377 NM SOUTHEAST OF MISAWA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 11 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A FULLY
EXPOSED, LOW LEVEL CIRCULATION CENTER, WITH NO SIGNIFICANT
CONVECTION ASSOCIATED WITH IT. TS 07W IS ON THE SOUTHWESTERN SIDE
OF A STR AND THEREFORE CONTINUES TRACKING NORTH-NORTHWEST. SYSTEM
IS SHALLOW, WITH A DEEP DRY AIR MASS ABOVE AND THE LOW-LEVEL
CIRCULATION IS LIMITED TO APPROXIMATELY 700MB AND BELOW. THE
INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON PERSISTENCE, BUT ALSO ON LACK OF CONVECTION AND GRADUAL
DISSIPATION OF THE SYSTEM.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: STR TO THE NORTH-EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T1.5 - 25 KTS
   CIMSS ADT: 25 KTS AT 130600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 20-25 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: WEAK EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 07W IS EXPECTED TO CONTINUE TRACKING
NORTH-NORTHWESTWARD ALONG THE SOUTHWESTERN SIDE OF THE SUBTROPICAL
RIDGE, TURNING NORTHWARD AROUND TAU 24. THE SYSTEM IS EXPECTED TO
STEADILY WEAKEN THROUGH THE FORECAST PERIOD, WITH INTENSITY
DROPPING TO 20 KTS BY TAU 24, AND THE DEEP DRY AIR LAYER WILL
PREVENT ANY FORM OF CONVECTIVE REGENERATION.

MODEL DISCUSSION: MODEL GUIDANCE IS IN GOOD AGREEMENT IN REGARDS TO
BOTH TRACK AND INTENSITY, WHILE THE JTWC FORECAST FALLS WITHIN
CLOSE SPREAD FROM THE MULTI-MODEL CONSENSUS.

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