WDPN32 PGTW 070300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (DANAS) WARNING NR 
013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.5N 121.4E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 25 NM NORTH-NORTHWEST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 19 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
STORM (TS) 05W (DANAS) WITH A VERY RAGGED AND DISORGANIZED
LOW-LEVEL STRUCTURE AFTER IT QUICKLY TRAVERSED ACROSS WESTERN
TAIWAN. DEEP CONVECTION IS NOW SPARSE, CONFINED TO A SMALL POCKET
WITHIN THE NORTHERN PERIPHERY OF THE LOW-LEVEL CIRCULATION CENTER
(LLCC). ENVIRONMENTAL ANALYSIS INDICATES THAT 05W IS IN A
MARGINALLY FAVORABLE ENVIRONMENT CHARACTERIZED BY MODERATE
EQUATORWARD OUTFLOW ALOFT, LOW (5-10 KTS) VERTICAL WIND SHEAR, AND
WARM (28-29 C) SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS
PLACED WITH LOW CONFIDENCE BASED ON THE DISORGANIZED WIND FIELD IN
ANIMATED RADAR IMAGERY. THE INITIAL INTENSITY OF 45 KTS IS ASSESSED
WITH LOW CONFIDENCE BASED PRIMARILY ON THE 070000Z CIMSS DPRINT
ESTIMATE OF 45 KTS.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T2.5 - 35 KTS
   CIMSS DPRINT: 45 KTS AT 070000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: LOW
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

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

FORECAST DISCUSSION: 05W IS FORECAST TO CONTINUE TRACKING
NORTH-NORTHEASTWARD, ALONG THE NORTHWESTERN PERIPHERY OF THE
NEAR-EQUATORIAL RIDGE THROUGH TAU 24. NEAR TAU 24, RIDGING WILL
EXTEND OVER TO THE NORTH OF THE VORTEX, WHICH WILL TURN THE SYSTEM
SHARPLY WESTWARD TOWARDS MAINLAND CHINA. A SECOND LANDFALL IS
FORECAST TO OCCUR AROUND TAU 30-36. A WESTWARD TO SOUTHWESTWARD
TRACK WILL THEN CONTINUE THROUGH THE REMAINDER OF THE FORECAST
PERIOD AS THE REMNANT VORTEX TRACKS FURTHER INLAND. REGARDING
INTENSITY, 05W IS FORECAST TO MAINTAIN INTENSITY OR SLIGHTLY WEAKEN
FURTHER OVER THE NEXT 24 HOURS AS IT TRIES TO RECUPERATE AFTER ITS
INITAL LANDFALL WITHIN TAIWAN. ENVIRONMENTAL CONDITIONS ARE
EXPECTED TO BE MARGINAL FOR ANY CHANCES OF REINTENSIFICATION
THOUGH. OUTFLOW IS FORECAST TO ALMOST ENTIRELY CEASE AND
NORTHEASTERLY SHEAR WILL BEGIN INCREASING. AFTER THE SECOND
LANDFALL, 05W WILL RAPIDLY DETERIORATE WITH DISSIPATION NO LATER
THAN TAU 72. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT THROUGH TAU 36 WITH AN 89 NM CROSS-TRACK SPREAD AT TAU
36. AFTER TAU 36, BOTH CROSS-TRACK AND ALONG-TRACK SPREAD INCREASE
AS THE WEAKENED VORTEX TRACKS OVER LAND. THE MAIN OUTLIER IS GFS,
WHICH HAS THE SYSTEM TAKE A MUCH SHARPER SOUTH-SOUTHWESTWARD TURN, 
NEARLY BACK INTO THE TAIWAN STRAIT, AFTER TAU 36. THE JTWC TRACK 
FORECAST FOLLOWS MORE CLOSELY TO THE MAIN GROUPING OF GUIDANCE WITH 
OVERALL MEDIUM CONFIDENCE. INTENSITY GUIDANCE MOSTLY AGREES ON 
WEAKENING THROUGHOUT THE FORECAST PERIOD, WITH THE EXCEPTION OF 
COAMPS-TC (GFS BASED), WHICH REINTENSIFIES THE SYSTEM FROM TAU 12 TO 
36. THE JTWC INTENSITY FORECAST IS ALSO PLACED WITH MEDIUM 
CONFIDENCE, IN LINE WITH THE MULTI-MODEL CONSENSUS.  

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