簽到天數: 1650 天 [LV.Master]伴壇終老
|
老農民版夜神月|2021-9-14 17:08
|
顯示全部樓層
JTWC降格TS,將在長三角近海打轉後朝日韓方向而去
19W CHANTHU 210914 0600 30.7N 124.3E WPAC 45 988 WDPN32 PGTW 140900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 19W (CHANTHU) WARNING
NR 033//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
INITIAL POSITION: 30.7N 124.3E
INITIAL INTENSITY: 45 KTS
GEOGRAPHIC REFERENCE: 310 NM WEST-SOUTHWEST OF SASEBO, JAPAN
MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 07 KTS
SIGNIFICANT WAVE HEIGHT: 20 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A PARTIALLY
EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC), WITH THE REMAINING
ASSOCIATED CONVECTION REMAINING TO THE NORTH AND WEST. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE LLCC SEEN IN
MSI. THE INITIAL INTENSITY OF 45 KNOTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON A 140230Z METOP-B ASCAT PASS WHICH SHOWS PEAK
WIND BARBS OF 40 KNOTS. THE OVERALL MARGINALLY UNFAVORABLE
CONDITIONS, ARE DUE TO THE LOW OCEAN HEAT CONTENT AND MEDIUM TO
STRONG VERTICAL WIND SHEAR, WHICH ARE OFFSET BY THE STRONG UPPER
LEVEL DIVERGENCE DISPLACED TO THE EAST OF THE LLCC.
INITIAL WIND RADII BASIS: SCATTEROMETER DATA
CURRENT STEERING MECHANISM: COL BETWEEN SUBTROPICAL RIDGE (STR) TO
THE NORTHWEST AND STR TO THE SOUTHEAST.
AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T3.5 - 55 KTS
RJTD: T3.5 - 55 KTS
RCTP: T3.5 - 55 KTS
CIMSS ADT: 32 KTS AT 140510Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
VWS: 5-10 KTS
SST: 28-29 CELSIUS
OUTFLOW: MODERATE POLEWARD AND EQUATORWARD
ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TS CHANTU IS EXPECTED TO REMAIN
QUASI-STATIONARY (QS) OVER THE NEXT TWO DAYS IN THE COL. AFTERWARD,
THE STR TO THE NORTHWEST WILL WEAKEN, ALLOWING THE SECONDARY STR TO
THE SOUTHEAST TO ASSUME STEERING AND DRIVE THE SYSTEM NORTHEASTWARD
THROUGH THE SEA OF JAPAN (SOJ), CROSSING NORTHERN HONSHU NEAR
MISAWA AND EXITING INTO THE PACIFIC OCEAN SHORTLY AFTER TAU 96. THE
MARGINALLY UNFAVORABLE CONDITIONS, EXACERBATED BY FURTHER COOLING
OF THE SSTS AS THE QS SYSTEM GENERATES UPWELLING OF DEEP COLD
WATER, WILL PROMOTE STEADY WEAKENING DOWN TO 35 KNOTS BY TAU 48.
AFTERWARD, THE NORTHEASTWARD TRACK INTO HIGHER VWS AND COLDER SSTS
OF THE SOJ WILL FURTHER WEAKEN IT TO 30KTS BY TAU 96 AS IT BECOMES
FULLY EXTRATROPICAL.
MODEL DISCUSSION: NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT.
HOWEVER, GIVEN THE UNCERTAINTY IN THE STORM MOTION AND DURATION IN
THE COL AREA, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST
THAT IS LAID CLOSE TO THE MODEL CONSENSUS.
FORECAST CONFIDENCE:
TRACK 0 - 72 HR: LOW
TRACK 72-120 HR: MEDIUM
INTENSITY 0 - 72 HR: LOW
INTENSITY 72-120 HR: MEDIUM//
NNNN
|
|
