WDPN32 PGTW 250900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (GAEMI) WARNING NR 
023//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.2N 119.8E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 93 NM WEST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
STORM (TS) 05W (GAEMI) ABOUT 40 NM OFFSHORE OF EASTERN CHINA WITH A
QUICKLY DETERIORATING CONVECTIVE STRUCTURE. INSTEAD OF TIGHTLY
WRAPPING INTO THE SYSTEM, THE CONVECTIVE BANDING IS STARTING TO
DRIFT AWAY FROM THE LOW-LEVEL CIRCULATION CENTER (LLCC).
OBSERVATIONS NEAR THE COAST OF CHINA OF AROUND 25 KTS REVEAL THAT
THE WIND FIELD OF 05W HAS BECOME VERY LOPSIDED. MUCH WEAKER WINDS
ARE PRESENT IN THE NORTHWESTERN QUADRANT THAN ELSEWHERE, SHOWING
THE INFLUENCE LAND INTERACTION IS HAVING ON THE SYSTEM. ENVIRONMENTAL 
CHARACTERISTICS INCLUDE: MODERATE RADIAL OUTFLOW ALOFT, MODERATE 
VERTICAL WIND SHEAR, AND WARM SEA SURFACE TEMPERATURES. THESE FACTORS 
ARE HIGHLY OFFSET BY THE EXTENSIVE LAND INTERACTION ON THE VORTEX, 
CAUSING THE ENVIRONMENT TO BE UNFAVORABLE FOR ANY FURTHER DEVELOPMENT. 
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE LLCC 
PEAKING THROUGH THE DRIFTING DEEP CONVECTION AS SEEN IN THE ANIMATED 
MSI. THE INITIAL INTENSITY OF 60 KTS IS ASSESSED WITH MEDIUM 
CONFIDENCE BASED ON THE OBJECTIVE AND SUBJECTIVE INTENSITY ESTIMATES 
LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE AND NEARBY SURFACE
OBSERVATIONS

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T4.0 - 65 KTS
   KNES: T3.0 - 45 KTS
   DEMS: T4.5 - 77 KTS
   CIMSS SATCON: 68 KTS AT 250600Z
   CIMSS ADT: 67 KTS AT 250600Z
   CIMSS AIDT: 57 KTS AT 250600Z
   CIMSS DMINT: 56 KTS AT 250534Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE RADIAL
   OTHER FACTORS: LAND INTERACTION.

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: LANDFALL OF TS 05W IS QUICKLY APPROACHING AND
IS EXPECTED TO OCCUR BY 251200Z. 05W IS FORECAST TO CONTINUE TRACKING 
ALONG THE SOUTHWEST PERIPHERY OF THE STR TO THE NORTHEAST THROUGHOUT 
THE REMAINDER OF THE FORECAST PERIOD AS IT TRACKS INLAND. 05W IS 
FORECAST TO DROP BELOW TROPICAL STORM STRENGTH NEAR TAU 24 AS THE 
TERRAIN WILL HAVE HAD AMPLE TIME TO ERODE THE VORTEX. FURTHER LAND 
INTERACTION WILL RAPIDLY WEAKEN 05W WITH DISSIPATION FORECAST TO OCCUR 
NO LATER THAN TAU 48.  

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN VERY GOOD AGREEMENT 
REGARDING THE TRACK OF 05W WITH A 120 NM CROSS-TRACK SPREAD AT TAU 36. 
NAVGEM DEPICTS A SLIGHTLY DIFFERENT TRACK AFTER TAU 36, TRACKING THE 
SYSTEM ALMOST STRAIGHT NORTHWARD. OTHERWISE, MODELS HIGHLY AGREE WHICH 
LENDS HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. INTENSITY GUIDANCE 
IS ALSO IN VERY GOOD AGREEMENT OF A WEAKENING TREND WITH DISSIPATION 
BY TAU 48. THEREFORE, THE JTWC INTENSITY FORECAST IS PLACED WITH HIGH 
CONFIDENCE. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: HIGH//
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