WDPN32 PGTW 060300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 05W (DANAS) WARNING NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.6N 118.3E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 274 NM SOUTHWEST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TYPHOON 05W
(DANAS) WITH DEEP CENTRAL CONVECTION TIGHTLY ROTATING AROUND A
FULLY OBSCURED LOW-LEVEL CIRCULATION CENTER (LLCC). A SECONDARY
SWATH OF CONVECTION CAN BE SEEN OFFSET OFF TO THE EAST, SOUTH OF
TAIWAN. 05W HAS STARTED TO PICK UP TRACK SPEED IN THE
NORTH-NORTHEASTWARD DIRECTION, AS THE STEERING PATTERN BECOMES MORE
DEFINED. A 052333Z GMI 89 GHZ MICROWAVE IMAGE REVEALED A DEFINED
MICROWAVE EYE WITH SPIRALING CONVECTION SURROUNDING THE SOUTHERN,
WESTERN, AND NORTHERN PORTIONS OF THE CIRCULATION. ENVIRONMENTAL
ANALYSIS INDICATES THAT 05W IS IN A HIGHLY FAVORABLE ENVIRONMENT
CHARACTERIZED BY STRONG POLEWARD AND EASTWARD OUTFLOW, LOW (5-10
KTS) VERTICAL WIND SHEAR, AND WARM (29-30 C) SEA SURFACE
TEMPERATURES. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON THE MICROWAVE EYE IN THE MENTIONED GMI IMAGE. THE INITIAL
INTENSITY OF 70 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE
AGENCY DVORAK AND OBJECTIVE INTENSITY ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: THE NORTHWESTERN PERIPHERY OF A DEEP
LAYER NEAR-EQUATORIAL RIDGE CENTERED TO THE SOUTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T5.0 - 90 KTS
   DEMS: T4.5 - 77 KTS
   CIMSS ADT: 51 KTS AT 060000Z
   CIMSS AIDT: 57 KTS AT 060000Z
   CIMSS DPRINT: 64 KTS AT 060000Z
   CIMSS DMINT: 62 KTS AT 052333Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD

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: TY 05W IS FORECAST TO CONTINUE TRACKING
NORTH-NORTHEASTWARD ALONG THE NORTHWESTERN PERIPHERY OF THE
NEAR-EQUATORIAL RIDGE TO THE SOUTHEAST THROUGH TAU 36. NEAR TAU 36,
RIDGING IS EXPECTED TO BUILD IN TO THE NORTH OF THE SYSTEM, WHICH
WILL INITIATE A SHARP WESTWARD TURN INTO MAINLAND CHINA. 05W WILL
THEN CONTINUE ON A GENERALLY WEST-SOUTHWESTWARD TRACK THROUGH THE
REMAINDER OF THE FORECAST PERIOD AS THE REMNANT VORTEX TRACKS
FURTHER INLAND. REGARDING INTENSITY, 05W IS FORECAST TO CONTINUE
INTENSIFYING THROUGH TAU 12 AS THE ENVIRONMENT REMAINS HIGHLY 
CONDUCIVE. HOWEVER, AFTER TAU 12, INTERACTION WITH THE WESTERN COAST 
OF TAIWAN WILL DISRUPT THE VORTEX AND WEAKEN THE SYSTEM. THIS 
WEAKENING TREND IS FORECAST TO PERSIST THROUGH TAU 48 AS 05W ENTERS A 
POOL OF COOL WATER THAT EXTENDS SOUTHWARD, TO AROUND 28N, AND 
NORTHERLY SHEAR INCREASES. AFTER TAU 48, THE RUGGED TERRAIN OF 
EASTERN CHINA WILL CAUSE 05W TO QUICKLY WEAKEN WITH DISSIPATION 
FORECAST TO OCCUR NO LATER THAN TAU 96. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT THROUGH TAU 48 WITH A 101 NM CROSS-TRACK SPREAD AT TAU
48. AFTER TAU 48, MODELS BEGIN TO DIVERGE AS SOME VORTEX TRACKERS
HAVE 05W MAKE A SHARP SOUTH-SOUTHWESTWARD TURN WITHIN THE TAIWAN
STRAIT (NAVGEM AND GFS). THE REMAINDER OF GUIDANCE TAKES THE SYSTEM
FURTHER INLAND, AND THE JTWC FOLLOWS THIS SCENARIO MORE CLOSELY.
OVERALL, THE JTWC TRACK FORECAST IS PLACED WITH MEDIUM CONFIDENCE
THROUGH TAU 72 AND LOW CONFIDENCE THEREAFTER. INTENSITY GUIDANCE
PAINTS AN INTERESTING PICTURE, ON ONE HAND, MANY RAPID
INTENSIFICATION (RI) AIDS ARE TRIGGERING AND DEPICT THE SYSTEM
REACHING 95-110 KTS IN 24 HOURS. ON THE OTHER HAND, ALL NON-RI AIDS
DEPICT WEAKENING FROM TAU 0. THIS IS INTERPRETED TO SHOW THAT THE
CURRENT ENVIRONMENT IS FAVORABLE FOR RI, HOWEVER, TERRAIN
INTERACTION WITH TAIWAN IS WHAT WILL BE THE MAIN HINDRANCE AND
DISALLOW ANY FURTHER INTENSIFICATION. THE JTWC INTENSITY FORECAST
IS PLACED HIGHER THAN CONSENSUS THROUGH TAU 12 AND THEN CLOSE TO
CONSENSUS THEREAFTER WITH LOW CONFIDENCE. THE POSSIBILITY
FOR MORE OR LESS LAND INTERACTION WITH WESTERN TAIWAN COULD HEAVILY
AFFECT INTENSITIES AS 05W TRAVERSES THE STRAIT.

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