WDPN31 PGTW 200300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01W (NOKAEN) WARNING NR 
022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.3N 129.1E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 494 NM EAST-NORTHEAST OF MANILA,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 13 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A HIGHLY
ASYMMETRIC, AND DISORGANIZED CIRCULATION, ELONGATED ALONG A ROUGHLY
NORTH-SOUTH AXIS. CONVECTION CONTINUES TO DEVELOP AND PERSIST ALONG
THE CONVERGENCE LINE WHERE THE WESTERN END OF A STATIONARY BOUNDARY
MEETS THE LOW-LEVEL SOUTHERLY FLOW ON THE EASTERN FLANK OF TS 01W.
A PARTIAL 200109Z ASCAT-C PASS REVEALED GALE-FORCE WINDS OF 35-40
KNOTS ALONG THE NORTHWESTERN PERIPHERY OF THE LOW LEVEL
CIRCULATION CENTER (LLCC). THE MAJORITY OF THE HIGHER WINDS ARE
EMBEDDED UNDER THE PERSISTENT CONVECTION, THOUGH A SMALL REGION
EXTENDS FURTHER TO THE SOUTHWEST AND IS SHOWN TO BE WRAPPING INTO
THE WESTERN SIDE OF THE LLCC. THE INITIAL POSITION IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON THE ELONGATED LLCC SEEN IN THE ANIMATED
MSI. THE INITIAL INTENSITY IS ASSESSED WITH HIGH CONFIDENCE BASED
ON THE ASCAT IMAGERY NOTED ABOVE. ENVIRONMENTAL CONDITIONS ARE
MARGINALLY UNFAVORABLE, CHARACTERIZED BY LOW VWS, WARM SSTS AND
ROBUST POLEWARD OUTFLOW OFFSET BY DRY AIR ENTRAINMENT INTO THE CORE
OF THE SYSTEM AND THE INTERACTION WITH THE STRONG COLD SURGE FLOW
AND STATIONARY FRONTAL BOUNDARY.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: COMPLEX INTERACTION BETWEEN A NARROW
EXTENSION OF A LOW-LEVEL SUBTROPICAL RIDGE (STR) AND THE WESTERN
END OF A STATIONARY FRONTAL BOUNDARY. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T1.5 - 25 KTS
   KNES: T1.5 - 25 KTS
   CIMSS SATCON: 46 KTS AT 192159Z
   CIMSS ADT: 43 KTS AT 190030Z
   CIMSS AIDT: 34 KTS AT 190030Z
   CIMSS D-MINT: 27 KTS AT 192159Z
   CIMSS D-PRINT: 27 KTS AT 200110Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 10-15 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY MID-LEVEL AIR

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE FORECAST HAS BEEN TRUNCATED TO 36
HOURS. 

FORECAST DISCUSSION: TROPICAL STORM (TS) 01W HAS CONTINUED ON A
GENERAL EASTWARD TRACK OVER THE LAST SIX HOURS BUT DUE TO THE HIGHLY 
ELONGATED AND DISORGANIZED CENTER, TRYING TO FIND THE CENTER OF TS 
01W IS LIKE TRYING TO FIND A SOBER SAILOR ON A MONDAY MORNING. THE 
SYSTEM IS ALREADY INTERACTING WITH A STATIONARY BOUNDARY, WITH THE 
SPIRAL BANDS ON THE NORTHEASTERN PERIPHERY MERGING WITH THE BOUNDARY 
BASED ON ANALYSIS OF THE ANIMATED MSI. TC 01W HAS ROUNDED THE NARROW 
RIDGE AXIS TO THE SOUTH AND IS ALREADY TREKKING NORTHEASTWARD, AND 
WILL CONTINUE TO TURN TO A MORE EASTWARD TRAJECTORY OVER THE NEXT 12 
HOURS AS IT MOVES ALONG THE SOUTHERN SIDE OF THE STATIONARY BOUNDARY. 
AFTER TAU 12, THE SYSTEM WILL TURN SOUTHEASTWARD AS IT IS PUSHED 
AHEAD OF THE FRONTAL BOUNDARY, WHICH WILL PUSH EQUATORWARD DUE TO A 
REINVIGORATED COLD SURGE. IN TERMS OF INTENSITY, THE STRONGEST WINDS 
REMAIN FIRMLY ENTRENCHED ON THE NORTHWESTERN SIDE OF THE CIRCULATION, 
ALONG THE TIGHT GRADIENT BETWEEN THE SURGE FLOW AND THE CIRCULATION 
ITSELF. THE SYSTEM ITSELF IS STEADILY WEAKENING AND BECOMING LESS 
ORGANIZED AND IS FORECAST TO CONTINUE TO WEAKEN THROUGH THE FORECAST 
PERIOD UNDER THE INFLUENCE OF INCREASING SHEAR AND DRY AIR 
ENTRAINMENT. DISSIPATION AS A SIGNIFICANT TROPICAL CYCLONE IS 
EXPECTED NO LATER THAN TAU 36. 

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN STRONG
AGREEMENT IN DEPICTING A GRADUAL TURN TOWARDS THE SOUTH-SOUTHEAST
OVER THE NEXT 36 HOURS. THE NAVGEM TURNS THE SYSTEM EARLIER AND
MORE SHARPLY THAN THE REMAINDER OF THE MODEL GUIDANCE WHICH IS
ENSCONCED IN GRADUALLY EXPANDING ENVELOPE THAT OPENS UP TO 100NM BY
TAU 36. THE JTWC FORECAST IS POSITIONED NEAR THE CONSENSUS MEAN AND
ON THE INNER EDGE OF THE ENVELOPE THROUGH THE FORECAST PERIOD, WITH
HIGH CONFIDENCE. INTENSITY GUIDANCE IS IN GENERALLY GOOD AGREEMENT,
WITH THE HAFS-A AND SHIPS PACKAGE SUPPORTING THE JTWC FORECAST,
WHILE THE HWRF AND COAMPS-TC DEPICT A MORE SLOWLY WEAKENING SYSTEM.
THE JTWC FORECAST IS PLACED NEAR THE HAFS-A TRACKER WITH HIGH
CONFIDENCE. 

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