WDPN31 PGTW 312100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (KIROGI) WARNING NR 
008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.2N 152.6E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 712 NM EAST-SOUTHEAST OF IWO TO
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
STORM (TS) KIROGI (11W) AS A MODERATELY SHEARED SYSTEM, WITH DEEP
CONVECTION OFFSET TO THE NORTHEAST OF A PARTIALLY EXPOSED LOW LEVEL
CIRCULATION CENTER (LLCC).  MODERATE POLEWARD OUTFLOW AND SOUTHERLY 
SHEAR IS OBSERVED ON SATELLITE DERIVED WATER VAPOR ANIMATED IMAGERY.  
ADDITIONALLY, LOW LEVEL SHALLOW CLOUD BANDS ARE OBSERVED WRAPPING 
INTO AN OBLONG LOW LEVEL CIRCULATION (LLC) OF SOUTHWEST TO NORTHEAST 
ORIENTATION IN A 311753Z SSMIS 91GHZ MICROWAVE IMAGE. THE INITIAL 
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED 
SSMIS MICROWAVE IMAGE. THE INITIAL INTENSITY OF 55 KTS IS ASSESSED 
WITH MEDIUM CONFIDENCE BASED ON MULTI-AGENCY SUBJECTIVE DVORAK 
ESTIMATES AVERAGING AT T3.5, AS WELL AS CIMSS ADT,AIDT, AND DPRINT 
OBJECTIVE ESTIMATES OF 61 KTS, 63 KTS, AND 41 KTS, RESPECTIVELY.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.0 - 45 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T4.0 - 65 KTS
   CIMSS ADT: 67 KTS AT 311740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 25-30 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD

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 KIROGI IS FORECAST TO CONTINUE ON A
NORTHWESTWARD TRACK THROUGH TAU 72, AND GRADUALLY SHIFT TO A WESTWARD 
TRACK THROUGH TAU 120. PASSING NEARBY YAKUSHIMA ISLAND POST TAU 96 AS 
AT TROPICAL DEPRESSION INTENSITY, THE SYSTEM IS ANTICIPATED TO ENTER 
THE EAST CHINA SEA AND LATER DISSIPATE POST TAU 120. ENVIRONMENTAL 
WIND SHEAR IN VICINITY OF TS KIROGI IS MODERATE AND EXPECTED TO 
INCREASE UP TO 40 KTS BY TAU 48, WHICH IS EXPECTED TO CAUSE THE 
INTENSITY TO GRADUALLY WEAKEN THROUGH TAU 120. 

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM TRACKING TS AROUND A
STR AND TURNING THE SYSTEM ON A NORTHEASTWARD TRAJECTORY NEAR TAU
48, NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT THAT TS KIROGI
WILL TRACK NORTHWESTWARD THROUGH TAU 72, AND THEN TRACK WESTWARD
INTO THE EAST CHINA SEA THEREAFTER. OF TANGENTIAL NOTE, THERE ARE
MULTIPLE MEMBERS OF BOTH THE ECMWF AND GFS ENSEMBLES THAT TAKE
FAIRLY ERRATIC PATHS FROM TAU 96 TO TAU 120, CONTRIBUTING TO THE
FORECAST TRACK AND INTENSITY CONFIDENCE OF MEDIUM. INTENSITY
CONSENSUS MEMBERS TREND DOWNWARD WITH TIME, BUT SHOW UNCERTAINTY AS
TO WHEN AND HOW MUCH WEAKENING OCCURS, WITH THE LARGEST DEVIATION
OF 35 KTS (55KTS TO 20 KTS) AT TAU 72.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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