WDPN32 PGTW 070900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (KHANUN)       
WARNING NR 045//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 28.0N 131.2E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 316 NM SOUTH-SOUTHEAST OF SASEBO, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 34 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP
CONVECTIVE BANDING WRAPPING INTO A BROAD, EXPOSED CENTER WITH
MULTIPLE MESOVORTICES ROTATING CYCLONICALLY AROUND A DEFINED
CENTROID. ANIMATED RADAR IMAGERY ALSO REVEALS A DEFINED CENTER WITH
WEAK BANDING AND FRAGMENTED CLOUD ELEMENTS ROTATING AROUND A
DEFINED CENTER. THERE IS MEDIUM CONFIDENCE IN THE INITIAL POSITION,
WHICH IS BASED ON THE CENTROID LOCATION. BASED ON HOURLY JMA RADAR
FIXES, THE CENTER APPEARS TO BE DRIFTING SLOWLY POLEWARD. ALTHOUGH
MODEST, A 070715Z SSMIS 37GHZ MICROWAVE IMAGE INDICATES IMPROVING
ORGANIZATION WITH DEEP CONVECTIVE BANDING WRAPPING TIGHTLY INTO A
DEFINED LOW-LEVEL CIRCULATION CENTER. ENVIRONMENTAL CONDITIONS HAVE
IMPROVED WITH EXPANDING RADIAL OUTFLOW, LOW VERTICAL WIND SHEAR
AND WARM SST (29C). HOWEVER, MID-LEVEL TO UPPER-LEVEL DRY AIR 
ENTRAINMENT IS LIKELY HINDERING DEVELOPMENT AT THIS TIME.

INITIAL WIND RADII BASIS: PERSISTENCE BUT ADJUSTED SLIGHTLY USING
SURFACE OBSERVATIONS FROM THE RYUKYU ISLANDS

CURRENT STEERING MECHANISM: WEAK SUBTROPICAL RIDGE (STR) POSITIONED
TO THE EAST AND NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 48 KTS AT 070438Z
   CIMSS ADT: 34 KTS AT 070540Z
   CIMSS AIDT: 56 KTS AT 070710Z
   D-PRINT: 45 KTS AT 070700Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL
   OTHER FACTORS: DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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 06W IS DRIFTING SLOWLY POLEWARD BASED ON A 
SERIES OF RECENT JMA RADAR FIXES AND IS FORECAST TO TRACK SLOWLY 
NORTHWARD TO NORTH-NORTHWESTWARD OVER THE NEXT 48 HOURS WHILE STEADILY 
INTENSIFYING TO 65 KNOTS NEAR SASEBO. TS 06W SHOULD INTENSIFY TO A 
PEAK OF 70 KNOTS BY TAU 60 PRIOR TO LANDFALL WEST OF BUSAN DUE TO 
IMPROVING, ROBUST POLEWARD OUTFLOW AND WARM SST VALUES. THE SYSTEM IS 
FORECAST TO GRADUALLY RE-MOISTEN, WHICH WILL ALSO AID IN THE 
REINTENSIFICATION PHASE. AFTER TAU 72, TS KHANUN WILL ACCELERATE OVER 
THE KOREAN PENINSULA AND BEGIN INTERACTING WITH THE LEADING EDGE OF A 
SUBTROPICAL SHORTWAVE TROUGH AND WEAK BAROCLINIC ZONE. DESPITE THE 
BAROCLINIC INFLUENCE, THE SYSTEM IS FORECAST TO DISSIPATE AS IT TRACKS 
INTO NORTH KOREA AND NORTHEAST CHINA.

MODEL DISCUSSION: WITH THE EXCEPTION OF THE UKMET ENSEMBLE MEAN, WHICH 
IS THE WESTERNMOST OUTLIER, AND NAVGEM, WHICH IS THE EASTERNMOST 
OUTLIER, NUMERICAL MODEL GUIDANCE SHOWS A TIGHT GROUPING OVER THE 
CENTRAL TO WESTERN KOREAN PENINSULA. THEREFORE, THERE IS MEDIUM 
OVERALL CONFIDENCE IN THE JTWC FORECAST TRACK. THIS UNCERTAINTY IS 
ALSO REFLECTED IN THE 070000Z GEFS AND EPS PROBABILISTIC GUIDANCE. 
OVERALL, THERE IS MEDIUM CONFIDENCE IN THE JTWC INTENSITY FORECAST 
WITH THE 070000Z COAMPS-TC ENSEMBLE SHOWING AN 80 TO 100 PERCENT 
PROBABILITY OF MODERATE INTENSIFICATION THROUGH TAU 30 DECREASING TO 
40 PERCENT PROBABILITY THROUGH TAU 54. 

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