WDPN33 PGTW 212100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (NEOGURI) WARNING NR 014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 29.3N 150.9E
   INITIAL INTENSITY: 110 KTS
   GEOGRAPHIC REFERENCE: 348 NM NORTH-NORTHWEST OF MINAMI TORI
   SHIMA
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 38 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS RAPIDLY
CYCLING CORE CONVECTION WITH A CLOUD-FILLED EYE FEATURE, WHICH
SUPPORTS THE INITIAL POSITION WITH HIGH CONFIDENCE. A 211849Z SSMIS
91GHZ MICROWAVE IMAGE REVEALS A WELL-DEFINED LARGE MICROWAVE EYE
FEATURE WITH A BREAK IN THE EYEWALL AND SPIRAL BAND OVER THE
SOUTHWEST QUADRANT. ANIMATED WATER VAPOR RGB SATELLITE IMAGERY 
INDICATES IMPROVING POLEWARD OUTFLOW INTO A DEEP UPPER-LEVEL TROUGH 
OVER HONSHU. THERE IS HIGH CONFIDENCE IN THE INITIAL POSITION BASED 
ON THE EIR SATELLITE IMAGERY AND THE SSMIS MICROWAVE IMAGE. THE 
INITIAL INTENSITY IS BASED ON THE CIMSS OBJECTIVE ESTIMATES AND THE 
AGENCY FINAL-T ESTIMATES.  

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE EAST, WITH A MAJOR SHORTWAVE TROUGH OVER JAPAN.  

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.5 - 127 KTS
   RJTD: T6.5 - 127 KTS
   RCTP: T6.0 - 115 KTS
   KNES: T5.5 - 102 KTS
   CIMSS SATCON: 116 KTS AT 211730Z
   CIMSS ADT: 104 KTS AT 211730Z
   CIMSS AIDT: 102 KTS AT 211730Z
   CIMSS D-MINT: 107 KTS AT 211547Z
   CIMSS D-PRINT: 100 KTS AT 211830Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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: AS THE SHORTWAVE TROUGH PROPAGATES EASTWARD,
TYPHOON 25W IS FORECAST TO SLOWLY TRACK NORTHEASTWARD TO EAST-
NORTHEASTWARD THROUGH ABOUT TAU 48. AFTER TAU 48, THE SYSTEM
IS ESSENTIALLY TRAPPED WITHIN COMPETING STEERING, WITH A STR TO THE
EAST AND WEST. CONSEQUENTLY, TRACK MOTIONS ARE EXPECTED TO BE SLOW
AND ERRATIC, WITH A GENERALLY NORTHWARD TO NORTH-NORTHWESTWARD
TRACK. AFTER TAU 96, ANOTHER MAJOR SHORTWAVE TROUGH WILL DEEPEN TO
THE NORTHWEST, WHICH WILL WEAKEN THE WESTERN STR AND ALLOW THE
SYSTEM TO ACCELERATE NORTH-NORTHEASTWARD. TY 25W APPEARS TO COMMENCE 
ETT NEAR TAU 24. HOWEVER, IT DOES NOT COMPLETE ETT UNTIL AFTER TAU 
120, WITH A SECOND FRONTAL ZONE TRACKING INTO THE NORTHERN PACIFIC AT 
THAT TIME. GRADUAL WEAKENING IS ANTICIPATED THROUGH THE FORECAST 
PERIOD DUE TO UPWELLING COOLER WATER AND PERIODS OF HIGH VERTICAL 
WIND SHEAR. EVENTUALLY, THE SYSTEM SHOULD TRACK OVER COOLER SST (24-
25C) AFTER TAU 108.             

MODEL DISCUSSION: JTWC FORECAST CONFIDENCE IS LOW THROUGH THE 
FORECAST PERIOD DUE TO THE COMPLEX, RAPIDLY EVOLVING STEERING PATTERN 
AND LARGE SPREAD IN DETERMINISTIC AND PROBABILISTIC GUIDANCE. THE 
211200Z EPS RUN DEPICTS A BIFURCATION WITH ABOUT 20-30 PERCENT OF THE 
SOLUTIONS INDICATING A PROLONGED WESTWARD TRACK THEN SHARP NORTH-
NORTHEASTWARD RECURVE TRACK EAST OF THE EASTERN COAST OF HONSHU. THE 
REMAINDER OF THE SOLUTIONS SUPPORT THE JTWC FORECAST TRACK, WITH A 
WIDE SPREAD OF MEANDERING SOLUTIONS EVENTUALLY SLOWLY TRACKING THE 
SYSTEM NORTH-NORTHEASTWARD TO NORTHEASTWARD WELL TO THE EAST OF 
JAPAN. DUE TO THE BIFURCATION IN EPS GUIDANCE, THE ENSEMBLE MEAN IS 
AN OUTLIER SKEWING THE JTWC CONSENSUS SLOWER AND FURTHER WEST OF THE 
JTWC FORECAST TRACK. THE 211200Z GEFS RUN SHOWS A SIMILAR SPREAD OF 
SOLUTIONS. WITH THE EXCEPTION OF EEM2 AND UEMI, THE DETERMINISTIC 
GUIDANCE SUPPORTS THE JTWC TRACK SCENARIO, WITH A 200-230NM CROSS-
TRACK SPREAD IN GUIDANCE FROM TAU 96 TO TAU 120. DUE TO THE 
COMPLICATED TRACK SCENARIO AND INTERACTIONS WITH TWO MAJOR SHORTWAVE 
TROUGHS, EXTRA-TROPICAL TRANSITION (ETT) IS EQUALLY COMPLEX. THE 
211200Z FSU CYCLONE PHASE PRODUCT FOR GFS DOESN'T SHOW ETT COMPLETE 
UNTIL THE 28TH, WITH TWO DISCRETE PERIODS OF ASYMMETRIC WARM-CORE 
CHARACTERISTICS.     

FORECAST CONFIDENCE:
   TRACK 00-72 HR: LOW
   TRACK 72-120 HR: LOW
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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