WDPN31 PGTW 310300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (KIROGI) WARNING NR 
005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.3N 154.5E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 566 NM EAST OF ANDERSEN AFB
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A COMPACT
CIRCULATION WITH DEEP CONVECTION FULLY OBSCURING THE LOW LEVEL
CIRCULATION CENTER (LLCC). AN UPPER-LEVEL LOW POSITIONED TO THE
NORTHWEST IS PROVIDING RIGOROUS POLEWARD OUTFLOW WHILE AT THE SAME
TIME INTRODUCING COOL DRY AIR INTO THE SYSTEMS WESTERN PERIPHERY. A
310011Z SUITE OF GMI MICROWAVE IMAGERY INDICATES THAT 11W HAS
SIGNIFICANTLY IMPROVED ITS CONVECTIVE SIGNATURE, WHICH NOW HAS A
DISCRETE MICROWAVE EYE EVIDENT IN BOTH 37GHZ AND 89GHZ. COMPARING
THE EYE LOCATION IN BOTH FREQUENCIES INDICATES THAT THE SYSTEM,
WHILE BETTER ORGANIZED, IS TILTED WITH HEIGHT. THE INITIAL POSITION
IS PLACED WITH MEDIUM CONFIDENCE BASED ON MSI AND GMI IMAGERY. THE
INITIAL INTENSITY OF 55 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON THE NEWLY FORMED MICROWAVE EYE IN GMI IMAGERY AS WELL AS
KNES DVORAK INTENSITY ESTIMATE AND CIMSS ADT INDICATING 51-55KTS
WHILE THE REMAINING GUIDANCE INDICATED SLIGHTLY LOWER.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR)
POSITIONED TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T3.0 - 45 KTS
   KNES: T3.5 - 55 KTS
   CIMSS ADT: 51 KTS AT 310110Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: OVER THE NEXT 12 HOURS, TS 11W (KIROGI) IS
FORECAST TO BEGIN TRACKING NORTH-NORTHWESTWARD UNDER THE STEERING
INFLUENCE OF THE STR TO THE EAST. BENEFITING FROM ITS COMPACT SIZE
AND FUELED BY THE ROBUST POLEWARD OUTFLOW PROVIDED BY THE
UPPER-LEVEL LOW TO THE NORTHWEST, 11W IS FORECAST TO REACH ITS PEAK
INTENSITY BY TAU 12 IN THE NEIGHBORHOOD OF 60KTS AND POSSIBLY A BIT
HIGHER. AFTER TAU 12, THE SYSTEM WILL CONTINUE ALONG THE WESTERN
PERIPHERY OF THE STR, CREATING A GRADUAL ARC TOWARD THE SOUTHERN
TIP OF KYUSHU. IN TERMS OF INTENSITY, AS 11W MOVES POLEWARD, SO TOO
DOES THE UPPER-LEVEL LOW, CREATING AN INCREASINGLY ADVERSE
ENVIRONMENT OF RISING SHEAR VALUES AND DRY AIR ENTRAINMENT THAT
WILL RESULT IN GRADUAL WEAKENING THROUGH THE REMAINING FORECAST
PERIOD.  

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT THROUGH
TAU 72, WITH ALL MEMBERS CLOSELY FOLLOWING THE JTWC FORECAST TRACK.
AFTER TAU 72 HOWEVER, ALONG TRACK AND CROSS TRACK SPREADING WORSENS
THROUGH THE REMAINING FORECAST PERIOD. FOR THESE REASONS THE JTWC
TRACK FORECAST IS PLACED INITIALLY WITH HIGH CONFIDENCE AND WITH
MEDIUM CONFIDENCE THERE AFTER. RELIABLE MODEL INTENSITY GUIDANCE IS
IN OVERALL GOOD AGREEMENT, WITH MOST MEMBERS INDICATING CONTINUED
INTENSIFICATION TO AROUND 60KTS BY TAU 12, AFTER WHICH A GRADUAL
WEAKENING TREND THROUGH THE FORECAST PERIOD. FOR THIS REASON THE
JTWC INTENSITY FORECAST IS PLACED WITH OVERALL MEDIUM CONFIDENCE.

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