Tropical Depression KOTO Advisory Bulletin (JTWC)
WTPN31 PGTW 020300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL DEPRESSION 33W (KOTO) WARNING NR 030//
RMKS/
1. TROPICAL DEPRESSION 33W (KOTO) WARNING NR 030
01 ACTIVE TROPICAL CYCLONE IN NORTHWESTPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
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WARNING POSITION:
020000Z --- NEAR 14.0N 111.5E
MOVEMENT PAST SIX HOURS - 135 DEGREES AT 04 KTS
POSITION ACCURATE TO WITHIN 035 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
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 WATER
REPEAT POSIT: 14.0N 111.5E
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FORECASTS:
12 HRS, VALID AT:
021200Z --- 13.5N 111.3E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
VECTOR TO 24 HR POSIT: 215 DEG/ 05 KTS
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24 HRS, VALID AT:
030000Z --- 12.7N 110.7E
MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
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REMARKS:
020300Z POSITION NEAR 13.9N 111.5E.
02DEC25. TROPICAL DEPRESSION 33W (KOTO), LOCATED APPROXIMATELY
221 NM EAST-SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED
SOUTHEASTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. TROPICAL
DEPRESSION (TD) 33W (KOTO) CONTINUES TO TRACK SOUTH SOUTHWESTWARD
AFTER A SIGNIFICANT SLOWING OF MOVEMENT AND A SLIGHT SHIFT TO THE
EAST. CONVECTIVE ACTIVITY AROUND THE CIRCULATION HAS CEASED.
MODERATE VERTICAL WIND SHEAR (15-20 KTS), DRY AIR ENTRAINMENT, AND
COOLER SEA SURFACE TEMPERATURES (26 C TO 27 C) HAVE CONTINUED TO
DEGRADE THE SYSTEM WITH MAX WIND SPEEDS FORECAST TO DROP TO 20 KTS
WITHIN 12 HOURS. 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
020000Z IS 1005 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 020000Z
IS 12 FEET.//
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Tropical Depression KOTO Forecast Advisory (JTWC)
WDPN31 PGTW 012100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 33W (KOTO) WARNING
NR 029//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 14.3N 111.2E
INITIAL INTENSITY: 30 KTS
GEOGRAPHIC REFERENCE: 196 NM EAST-SOUTHEAST OF DA NANG, VIETNAM
MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 04 KTS
SIGNIFICANT WAVE HEIGHT: 12 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL DEPRESSION (TD) 33W (KOTO) IS NOW TRACKING SOUTHWESTWARD
WITH A FULLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) THAT LACKS
DEEP CONVECTION AS DEPICTED BY ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY. ENVIRONMENTAL ANALYSIS SHOWS THE CIRCULATION
WILL CONTINUE THROUGH AN UNFAVORABLE ENVIRONMENT WITH WEAK OUTFLOW
ALOFT, MODERATE VERTICAL WIND SHEAR (15-20 KTS), DRY AIR
ENTRAINMENT, AND SEA SURFACE TEMPERATURES BETWEEN 26 C AND 27 C.
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON EIR
IMAGERY OF THE EXPOSED LLCC AND AGENCY FIXES. THE INITIAL INTENSITY
OF 30 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON SUBJECTIVE
AND OBJECTIVE INTENSITY ESTIMATES.
INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).
CURRENT STEERING MECHANISM: WEAK INFLUENCE FROM SUBTROPICAL RIDGE
(STR) TO THE NORTHWEST
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T1.5 - 25 KTS
DEMS: T1.5 - 25 KTS
CIMSS SATCON: 36 KTS AT 011752Z
CIMSS ADT: 25 KTS AT 011730Z
CIMSS AIDT: 26 KTS AT 011730Z
CIMSS D-MINT: 25 KTS AT 011752Z
CIMSS D-PRINT: 25 KTS AT 011830Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
VWS: 15-20 KTS
SST: 26-27 CELSIUS
OUTFLOW: WEAK EQUATORWARD
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: NOT APPLICABLE
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TROPICAL DEPRESSION (TD) 33W (KOTO) IS
FORECAST TO CONTINUE SOUTHWESTWARD AS A COMBINATION OF LOWER LEVEL
FLOW OUT OF THE NORTHEAST AND RIDGING OVER THAILAND SLOWLY PUSH THE
CIRCULATION ALONG THE EASTERN COAST OF VIETNAM. AFTER TAU 24 THE
INFLUENCE OF THE STRENGTHENING RIDGE WILL PUSH TD KOTO SOUTHWESTWARD
AT A QUICKER PACE. THE SYSTEM WILL SLOWLY WEAKEN AS IT CONTINUES TO
ENCOUNTER HIGH VERTICAL WIND SHEAR AND SIGNIFICANT DRY AIR
ENTRAINMENT. TD KOTO IS FORECAST TO DISSIPATE OVER WATER BY TAU 48.
MODEL DISCUSSION: CROSS TRACK SPREAD AMONGST AVAILABLE MODEL
GUIDANCE IS UP TO 110 NM AT TAU 48 WITH ECMWF STANDING BY THE
NORTHERN TRACK ACROSS THE SOUTHERN PORTION OF THE VIETNAM. NAVGEM
DEPICTS A MORE SOUTHERLY TRACK KEEPING THE CIRCULATION FIRMLY
WITHIN THE OPEN WATERS OF THE WESTERN SOUTH CHINA SEA. THE JTWC
FORECASTED TRACK IS PLACED CLOSE TO THE MULTI MODEL CONSENSUS WITH
MEDIUM CONFIDENCE. INTENSITY GUIDANCE REFLECTS A BETTER CONSENSUS
WITH A 10 KT SPREAD. THE JTWC FORECASTED INTENSITY ALSO FOLLOWS THE
MULTI MODEL CONSENSUS CLOSELY WITH HIGH CONFIDENCE.
FORECAST CONFIDENCE:
TRACK 00-72 HR: MEDIUM
INTENSITY 00-72 HR: HIGH//
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