Tropical Storm CHAMPI Advisory Dom, 27-06

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (CHAMPI) WARNING NR
025//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
   INITIAL POSITION: 29.8N 141.6E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 344 NM SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 17 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) LOOP DEPICTS AN
EXPOSED LOW-LEVEL CIRCULATION (LLC) WEST OF A SMALL AREA OF
CONVECTION, AS THE SYSTEM CONTINUES WEAKENING AND UNRAVELLING DUE TO
HIGH VWS IN THE STRONG PREVAILING WESTERLIES. THE INITIAL POSITION
IS PLACED WITH HIGH CONFIDENCE BASED ON A RAGGED LOW-LEVEL
CIRCULATION FEATURE AS SEEN IN THE 262138Z SSMIS 91GHZ MICROWAVE
IMAGE AND THE MSI LOOP. THE INITIAL INTENSITY OF 35 KTS IS IN LINE
WITH MULTIPLE AGENCY DVORAK FIXES AND IS ASSESSED WITH HIGH
CONFIDENCE DUE TO THE RAPID WEAKENING STATE OF THE SYSTEM AS IT
ENCOUNTERS THE COOLER SSTS AND THE AFOREMENTIONED HIGHER VWS.
INITIAL WIND RADII BASIS: SCATTEROMETER DATA. WIND RADII IN LINE
WITH THE NORTHEAST QUADRANT BASED ON 270101Z PARTIAL ASCAT-B PASS.
CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF THE STR TO THE
EAST.
AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T2.5 - 35 KTS
   RJTD: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   CIMSS ADT: 31 KTS AT 262330Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 20-25 KTS
   SST: 24-25 CELSIUS
   OUTFLOW: MODERATE POLEWARD
ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: HIGH
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TS CHAMPI CONTINUES TRACKING NORTHEAST WELL TO
THE EAST OF HONSHU, JAPAN ALONG THE POLEWARD SIDE OF THE STEERING
STR. TS CHAMPI WILL BE 251NM EAST-SOUTHEAST OF YOKOSUKA, JAPAN BY
TAU 12 AND CONTINUE WEAKENING UNDER THE HIGHLY UNFAVORABLE
ENVIRONMENT. TS 06W WILL BEGIN INTERACTING WITH THE BAIU BOUNDARY
WITHIN THE NEXT 12-24 HOURS, AS IT STARTS THE EXTRA-TROPICAL
TRANSITION AND TRANSFORMS INTO A GALE-FORCE COLD-CORE LOW WITH
AN EXPANSIVE WIND FIELD AS IT EMBEDS IN THE BAROCLINIC ZONE
BETWEEN TAUS 24-36.
MODEL DISCUSSION: NUMERIC MODELS REMAIN TIGHT THROUGH TAU 24 WITH
A MAX CROSS-TRACK SPREAD OF 80NM, SPREADING TO A MAXIMUM OF 200NM
BY TAU 36 AS ECMWF IS NOW THE SOLE LEFT OUTLIER LENDING HIGH
CONFIDENCE IN THE JTWC TRACK FORECAST. THE JTWC INTENSITY
FORECAST IS ALSO IN GOOD AGREEMENT WITH MODEL SOLUTIONS WHICH
SHOWS A STEADY WEAKENING TREND.
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: MEDIUM//
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