WDPN31 PGTW 200300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 16W (SIXTEEN) 
WARNING NR 031//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.0N 130.9E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 482 NM SOUTH-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A LOW LEVEL
CIRCULATION CENTER (LLCC) POSITIONED UNDER THE NORTHERN CANOPY OF A
CONSOLIDATING SYSTEM OF DEEP CONVECTION WITH ASSOCIATED RADIAL
OUTFLOW ALOFT. A PARTIAL 192125Z SSMIS 91GHZ PASS SHOWS FLARING
CONVECTION IN THE SOUTHERN PERIPHERY OF THE LLCC. A PARTIAL 200048Z 
ASCAT-B PASS INDICATES THE LLCC HAS AN AREA OF 15-20KT WINDS IN THE
NORTHERN PERIPHERY WITH WEAKER WINDS TO THE NORTHWEST AND SOUTHWEST
QUADRANTS. THE INITIAL POSITION IS ASSESSED WITH MEDIUM CONFIDENCE
BASED OFF THE AFOREMENTIONED MSI ANALYSIS AND THE PGTW SATELLITE
FIX. THE INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON THE PGTW DVORAK ESTIMATE.

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

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
NORTHEAST OFF THE SOUTHEAST COAST OF HONSHU.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   KNES: T1.5 - 25 KTS

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

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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 16W WILL CONTINUE TO TRACK NORTHWEST ALONG
THE SOUTHWEST PERIPHERY OF THE DEEP STR BY TAU 48, THEN TURN
NORTHWARD BY TAU 60 AS IT APPROACHES A BREAK IN THE STR, THEN
ACCELERATE NORTH-NORTHEASTWARD THROUGH THE REMAINDER OF THE
FORECAST ALONG THE GRADIENT BETWEEN THE STR AND A MID-LATITUDE
TROUGH APPROACHING FROM THE WEST. THE SYSTEM IS FORECAST TO
STEADILY INTENSIFY AND PEAK AT 45 KTS BY TAU 36 AS IT APPROACHES
THE STR AXIS. HOWEVER, BY TAU 48 AS IT TRACKS FURTHER NORTHWEST THE
SYSTEM WILL BEGIN TO INTERACT WITH STRONG VWS WITH SIGNIFICANT
NORTHERLY UPPER LEVEL WIND FLOW. BY TAU 72, TD 16W WILL BE
COMPLETELY UNDER THE STRONG NORTHEASTERLY WINDS ALOFT, AND WILL
EXPERIENCE DRAMATICALLY INCREASED VWS AND UPPER LEVEL CONVERGENCE,
LEADING TO FAIRLY RAPID DISSIPATION NO LATER THAN TAU 96. 

MODEL DISCUSSION: TRACK GUIDANCE IS IN FAIR AGREEMENT ON THE
RECURVE SCENARIO, WITH A CROSS-TRACK SPREAD OF 95 NM AT TAU 24 THAT
SPREADS RAPIDLY TO 250 NM BY TAU 48. AFTER TAU 72, THE SYSTEM 
ACCELERATES NORTHEASTWARD AS IT FALLS UNDER THE INFLUENCE OF THE 
WESTERLIES. THE UKMET ENSEMBLE MEAN IS THE LEFT OUTLIER WHILE ECMWF 
IS THE RIGHT OUTLIER, LENDING TO THE JTWC TRACK BEING HEDGED 
SLIGHTLY TO THE RIGHT AND AHEAD OF THE MULTI-MODEL CONSENSUS. THE 
JTWC INTENSITY FORECAST IS IN FAIR AGREEMENT WITH THE INTENSITY 
CONSENSUS (ICNW) BY TAU 36. AFTERWHICH, THE JTWC INTENSITY FORECAST 
IS HEDGED LOWER THAN ICNW DUE TO SYSTEM INTERACTION WITH SIGNIFICANT 
VWS AS TD 16W APPROACHES TAU 48 SOUTH-SOUTHWEST OF KADENA.

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