WTPS12 NFFN 080423
TROPICAL DISTURBANCE ADVISORY NUMBER B7 ISSUED FROM RSMC NADI
Feb 080424 UTC.

EX-TROPICAL CYCLONE OSAI [TD08F] CENTRE 997HPA WAS LOCATED NEAR 17.8S
164.4W AT 080300 UTC.  POSITION FAIR BASED ON VIS/EIR IMAGERY AND
PERIPHERAL SURFACE REPORTS.  
CYCLONE MOVING EAST SOUTHEAST AT ABOUT 6 KNOTS.  MAXIMUM 10-MINUTE
AVERAGE WINDS NEAR THE CENTRE ESTIMATED AT ABOUT 30 KNOTS.  

LLCC FULLY EXPOSED WITH DEEP CONVECTION SHEARED TO THE EAST. EX-TC
OSAI LIES IN AN AREA OF HIGH SHEARED ENVIRONMENT WITH GOOD UPPER
DIVERGENCE TO THE EAST OF THE SYSTEM. SST AROUND 29 DEGREES CELSIUS.
CYCLONIC CIRCULATION EXTENDS UPTO THE 700HPA. THE SYSTEM IS STEERED
EAST-SOUTHEAST ALONG THE SOUTHERN PERIPHERY OF THE NEAR-EQUATORIAL
RIDGE TO THE NORTHEAST. DVORAK ANALYSIS BASED ON SHEARED PATTERN.
YIELDING DT=2.5, MET AND PT AGREE WITH FT BASED ON DT. THUS,
T2.0/2.5/S0.0/24HRS.

FORECASTS :
AT 12 HRS VALID AT 081500 UTC 18.4S 164.5W MOV SSW AT 02 KT WITH 30
KT CLOSE TO CENTRE
AT 24 HRS VALID AT 090300 UTC 18.8S 164.6W MOV WSW AT 02 KT WITH 30
KT CLOSE TO CENTRE

OUTLOOK :
AT 36 HRS VALID AT 091500 UTC 18.9S 165.1W MOV W AT 02 KT WITH 30 KT
CLOSE TO CENTRE
AT 48 HRS VALID AT 100300 UTC 19.0S 165.7W MOV W AT 02 KT WITH 30 KT
CLOSE TO CENTRE

THIS WILL BE THE FINAL TROPICAL DISTURBANCE ADVISORY ISSUED FOR
TD08F.

全球热带气旋监测公报

WTPS32 PGTW 081500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 11P (OSAI) WARNING NR 007//
RMKS/
1. TROPICAL CYCLONE 11P (OSAI) WARNING NR 007    
   03 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   081200Z --- NEAR 18.2S 163.4W
     MOVEMENT PAST SIX HOURS - 120 DEGREES AT 09 KTS
     POSITION ACCURATE TO WITHIN 040 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   REPEAT POSIT: 18.2S 163.4W
    ---
   FORECASTS:
   12 HRS, VALID AT:
   090000Z --- 18.7S 163.0W
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
081500Z POSITION NEAR 18.3S 163.3W.
08FEB24. TROPICAL CYCLONE 11P (OSAI), LOCATED APPROXIMATELY 272
NM NORTHWEST OF RAROTONGA, HAS TRACKED EAST-SOUTHEASTWARD AT 09
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) AND 
SHORTWAVE INFRARED (SWIR) SATELLITE IMAGERY SHOWS A RAGGED AND EXPOSED 
LOW LEVEL CIRCULATION CENTER (LLCC). THE LLCC REMAINS DEVOID OF 
CONVECTIVE ACTIVITY DUE TO THE STRONG UPPER-LEVEL WESTERLIES ABOVE THE 
CIRCULATION. THE INITIAL POSITION IS SET WITH HIGH CONFIDENCE BASED ON 
THE EXPOSED LLCC IN THE EIR AND SWIR. THE INITIAL INTENSITY IS 
ASSESSED WITH HIGH CONFIDENCE BASED ON A 080900Z ASCAT-B BULLSEYE PASS 
SHOWING 25-30 KNOT MAXIMUM WINDS ALONG THE WESTERN PERIPHERY AND 
ACROSS THE SOUTHERN OUTSKIRTS OF THE CIRCULATION. THE 080600Z BEST 
TRACK INTENSITY HAS BEEN REANALYZED TO 30 KNOTS BASED ON THIS ASCAT AS 
WELL AND THUS THE SYSTEM HAS ALREADY DISSIPATED BELOW THE 35 KNOT 
WARNING THRESHOLD. SHEAR IS CURRENTLY ASSESSED AT 30-40 KNOTS FROM THE 
WEST, WHILE DRY AIR HAS ENGULFED THE SYSTEM IN THE MID-LEVELS, LEAVING 
LITTLE TO NO OPPORTUNITY FOR REINTENSIFICATION THOUGH SOME OF THE 
GUIDANCE SUGGEST THAT IT COULD MAKE A COMEBACK AFTER TAU 72. TRACK 
GUIDANCE SHOWS AN ERRATIC, MEANDERING TRACK WITH A WIDE SPREAD IN THE 
MODELS WHICH SHOW OPTIONS TOWARDS MOST POINTS OF THE COMPASS. 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 081200Z IS 992 MB. MAXIMUM 
SIGNIFICANT WAVE HEIGHT AT 081200Z IS 15 FEET.
REFER TO TROPICAL CYCLONE 10P (NAT) FINAL WARNING (WTPS31 PGTW). 
REFER TO TROPICAL CYCLONE 12P (TWELVE) WARNINGS (WTPS33 PGTW) FOR SIX-
HOURLY UPDATES.//
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