Tropical Depression KRATHON (20W)

WTPN33 PGTW 032100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL DEPRESSION 20W (KRATHON) WARNING NR 027//
RMKS/
1. TROPICAL DEPRESSION 20W (KRATHON) WARNING NR 027    
   01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   031800Z --- NEAR 23.0N 120.9E
     MOVEMENT PAST SIX HOURS - 030 DEGREES AT 04 KTS
     POSITION ACCURATE TO WITHIN 025 NM
     POSITION BASED ON CENTER LOCATED BY A COMBINATION OF 
     SATELLITE, RADAR AND SYNOPTIC DATA
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   REPEAT POSIT: 23.0N 120.9E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   040600Z --- 23.6N 120.9E
   MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   VECTOR TO 24 HR POSIT: 285 DEG/ 02 KTS
    ---
   24 HRS, VALID AT:
   041800Z --- 23.7N 120.5E
   MAX SUSTAINED WINDS - 015 KT, GUSTS 025 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
032100Z POSITION NEAR 23.2N 120.9E.
03OCT24. TROPICAL DEPRESSION 20W (KRATHON), LOCATED APPROXIMATELY 130 
NM SOUTH-SOUTHWEST OF TAIPEI, TAIWAN, HAS TRACKED NORTH-NORTHEASTWARD 
AT 04 KNOTS OVER THE PAST SIX HOURS. COMPOSITE RADAR LOOP CLEARLY 
SHOWS THE SYSTEM HAS TRACKED DEEP INTO THE SOUTHEASTERN MOUNTAIN 
RANGES OF TAIWAN WITH PEAKS OVER 5000 FT. THE RUGGED TERRAIN HAS 
EFFECTIVELY ERODED MOST OF THE DEEP CONVECTON ASSOCIATED WITH TD 2OW 
AND DECAPITATED IT FROM THE REMNANT LOW LEVEL CIRCULATION CENTER. THE 
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE RADAR 
LOOP. THE INITIAL INTENSITY IS ALSO ASSESSED WITH MEDIUM CONFIDENCE 
BASED ON NEARBY SURFACE WIND AND MEAN SEA LEVEL OBSERVATIONS. TD 
KRATHON IS EXPECTED TO TRACK FURTHER NORTHWARD OVER THE MOUNTAIN 
RANGES AND DISSIPATE BY TAU 12, LIKELY SOONER. THIS IS THE FINAL 
WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WRNCEN PEARL HARBOR HI. 
THE
SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF REGENERATION. MINIMUM 
CENTRAL PRESSURE AT 031800Z IS 1002 MB.//
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WDPN33 PGTW 031500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 20W (KRATHON) WARNING NR 
026//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.7N 120.7E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 151 NM SOUTH-SOUTHWEST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: EASTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: OVER LAND

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A BROAD
AND DISORGANIZED MID-LEVEL CIRCULATION ASSOCIATED WITH TROPICAL
STORM 20W (KRATHON). SINCE MAKING LANDFALL THE SYSTEM HAS RAPIDLY
SLOWED DOWN AND DETERIORATED IN STRUCTURE AND INTENSITY, WITH
MINIMAL CONVECTIVE ACTIVITY. THE INITIAL POSITION IS PLACED WITH
MEDIUM CONFIDENCE BASED ON RADAR AND ENHANCED IT LOOPS. THE INITIAL
INTENSITY OF 45 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE
RAPID CONVECTIVE STRUCTURE WEAKENING AND DPRINT OBJECTIVE ESTIMATE
OF 44 KTS.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK.

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 15-20 KTS
   SST: OVER LAND
   OUTFLOW: WEAK POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: DUE TO RAPID DETERIORATION TRIGGERED
BY TERRAIN INTERACTION AND HIGH VERTICAL WIND SHEAR, THE SYSTEM IS
NOW FORECAST TO DISSIPATE OVER LAND BY TAU 24.

FORECAST DISCUSSION: TS 20W STALLED RIGHT AFTER LANDFALL TO A SPEED
OF 2 KTS AND AS A RESULT OF INTERACTION WITH RUGGED TERRAIN OF
SOUTH-CENTRAL TAIWAN ITS CURRENT INTENSITY DROPPED TO 45 KTS. THE
SYSTEM IS FORECAST TO TRACK NORTHWESTWARD, WHILE CONTINUING TO
WEAKEN DOWN TO 20 KTS BY TAU 24, AND THEREFORE DISSIPATE PRIOR TO 
REACHING THE STRAIT OF TAIWAN. REMNANTS OF THE SYSTEM WILL BE 
ABSORBED INTO THE PREDOMINANT NORTHEASTERLY FLOW ASSOCIATED WITH AN 
ONGOING COLD SURGE FLOW.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS CURRENTLY
DISPLAYING VERY ERRATIC GUIDANCE WITH NEARLY 180 DEGREE TRACK
DIRECTION VARIABILITY INDICATING A FURTHER WEAKENING OF THE VORTEX.
JTWC TRACK IS THEREFORE ASSESSED WITH LOW CONFIDENCE, BASED ON THE 
SUBTROPICAL RIDGE STEERING PATTERN. INTENSITY GUIDANCE HOWEVER 
REMAINS IN GOOD AGREEMENT, WITH ALL MODELS INDICATING FURTHER 
WEAKENING AND DISSIPATION BY TAU 24. AS A RESULT, THE JTWC INTENSITY 
FORECAST IS PLACED WITH MEDIUM CONFIDENCE.

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