WDPN31 PGTW 161500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 09W (NINE) WARNING 
NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.8N 134.8E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 603 NM SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 9 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS BUILDING
CONVECTION THAT CONTINUES TO COMPLETELY OBSCURE THE LOW LEVEL
CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH LOW
CONFIDENCE BASED ON THE LOW LEVEL CLOUD LINES PRESENT IN THE EIR
LOOP ALONG WITH WEAK LOW LEVEL BANDING FEATURES PRESENT IN A TIMELY
161240Z GMI 89GHZ COLOR COMPOSITE IMAGE. THE INITIAL INTENSITY OF
25 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON MULTIAGENCY
DVORAK CURRENT INTENSITY ESTIMATES OF T1.0 (25 KTS, PGTW) AND T1.5
(25 KTS, KNES), DATA FROM A 160856Z SMAP RETRIEVAL REFLECTING 20-25
KTS AND AN ADVANCED DVORAK TECHNIQUE CURRENT INTENSITY ESTIMATE OF
T1.7 (27 KTS).

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

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF THE DEEP STR
POSITIONED TO THE EAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.0 - 25 KTS
   KNES: T1.5 - 25 KTS
   CIMSS ADT: 27 KTS AT 161140Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: MEDIUM
   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: TD 09W WILL TRACK GENERALLY
NORTH-NORTHWESTWARD THROUGH TAU 48 UNDER THE INFLUENCE OF THE
STEERING RIDGE. DURING THIS TIME, FAVORABLE TO MARGINALLY FAVORABLE
ENVIRONMENTAL CONDITIONS WILL ALLOW FOR GRADUAL INTENSIFICATION TO
55 KTS BY THIS TIME. THEREAFTER, A REPOSITIONING OF THE STEERING
RIDGE WILL LEAD TO A GENERALLY WEST-NORTHWESTWARD TRACK.
ADDITIONALLY, THE UPPER LEVEL CYCLONIC CIRCULATION CURRENTLY
POSITIONED TO THE NORTH OF THE SYSTEM WILL TRACK WESTWARD OVER
MAINLAND CHINA BY THIS TIME AND POTENTIALLY ENHANCE THE OUTFLOW OF
THE SYSTEM. THIS ENHANCED OUTFLOW, COUPLED WITH LOW VWS AND
CONTINUED WARM SST, WILL ALLOW FOR CONTINUED INTENSIFICATION
THEREAFTER, WITH THE SYSTEM REACHING TYPHOON STRENGTH BY TAU 72.
AFTER TAU 96, VWS WILL BECOME UNFAVORABLE (GREATER THAN 20 KTS) AND
THE SYSTEM WILL BEGIN TO WEAKEN. 

MODEL DISCUSSION: NUMERICAL MODEL SOLUTIONS CONTINUE TO REFLECT A
HIGH DEGREE OF UNCERTAINTY IN THE TRACK GUIDANCE THAT LIKELY STEMS
FROM THE DYNAMIC REPOSITIONING OF THE STEERING RIDGE AND IN THE
UNCERTAINTY IN TIMING OF STORM INTENSIFICATION. THE SPREAD IN MODEL
TRACK GUIDANCE IS BOUND BY THE GFS DETERMINISTIC AND ENSEMBLE
SOLUTIONS THAT TRACK THE VORTEX NORTH OF OKINAWA, JAPAN BETWEEN
TAUS 72 AND 96 AND THE UKMET ENSEMBLE AND ECMWF DETERMINISTIC
SOLUTIONS THAT TRACK THE STORM CENTER SOUTH OF OKINAWA AT TAU 96.
THE JTWC FORECAST TRACK IS HEDGED BETWEEN THESE TRACK AND IS PLACED
ALONG THE MULTI-MODEL CONSENSUS WITH ONLY MEDIUM CONFIDENCE DUE TO
TO THE SPREAD IN THE MODEL SOLUTIONS. 

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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