WDPN31 PGTW 140300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 29W (NAKRI) WARNING NR 
024//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 34.9N 151.0E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 555 NM EAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: EASTWARD AT 25 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TIGHTLY CURVED 
BANDING WRAPPING INTO THE WELL-DEFINED UPPER-LEVEL CIRCULATION. 
ANIMATED MSI ALSO DEPICTS EXTENSIVE COLD AIR STRATOCUMULUS AND DRY AIR 
ADVECTING OVER THE WESTERN SEMICIRCLE AND WRAPPING INTO THE CORE. A 
132342Z METOP-B ASCAT IMAGE REVEALS A SLIGHTLY ASYMMETRIC WINDFIELD, 
WITH A SMALL PATCH OF 65-70KTS CONFINED TO THE SOUTHEASTERN QUADRANT. 
ENVIRONMENTAL ANALYSIS INDICATES A HIGHLY UNFAVORABLE ENVIRONMENT, 
CHARACTERIZED BY HIGH (35-40 KTS) VERTICAL WIND SHEAR AND COOL (25-26 
C) SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS PLACED WITH HIGH 
CONFIDENCE BASED ON THE AFOREMENTIONED 132342Z METOP-B ASCAT DATA. THE 
INITIAL INTENSITY IS ALSO PLACED WITH MEDIUM CONFIDENCE BASED ON THE 
132342Z ASCAT IMAGE, SUPPORTED BY AGENCY DVORAK FIXES AND THE 
OBJECTIVE INTENSITY ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: 132342Z METOP-B SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: THE NORTHERN EXTENT OF A SUBTROPICAL
RIDGE (STR) TO THE SOUTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T4.0 - 65 KTS
   CIMSS ADT: 49 KTS AT 140040Z
   CIMSS AIDT: 63 KTS AT 140040Z
   CIMSS D-PRINT: 63 KTS AT 140040Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 30+ KTS
   SST: 25-26 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL STROM (TS) 29W (NAKRI) WILL MAINTAIN
ITS EASTWARD TRACK, CONTINUING TO ACCELERATE ALONG THE NORTHERN 
PERIPHERY OF THE STR TO ITS SOUTH AS IT BECOMES INCREASINGLY 
INFLUENCED BY THE UPPER-LEVEL JET. 29W HAS BEGUN EXTRATROPICAL 
TRANSITION (ETT) AND IS EXPECTED TO COMPLETE ETT NO LATER THAN TAU
24. 29W IS FORECAST TO MAINTAIN INTENSITY THROUGH TAU 12, BEFORE
WEAKENING SLIGHTLY WHEN IT BECOMES FULLY EXTRATROPICAL AT TAU 24. 

MODEL DISCUSSION: DETERMINISTIC TRACK MODELS ARE IN TIGHT AGREEMENT, 
WITH ONLY MINOR VARIATIONS IN TRACK SPEED OCCURRING AT TAU 24, 
SUPPORTING THE JTWC TRACK FORECAST WITH HIGH CONFIDENCE. RELIABLE 
INTENSITY GUIDANCE IS LESS CERTAIN ON INTENSITY; HOWEVER, ALL MODELS 
ARE IN GOOD AGREEMENT THAT 29W WILL STEADILY WEAKEN BEGINNING AT TAU 
12. AS A RESULT, THE JTWC INTENSITY FORECAST IS PLACED WITH HIGH 
CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: HIGH//
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