Tropical Cyclone GEZANI (21S)

WTXS31 PGTW 080300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 26S (TWENTYSIX) WARNING NR 005//
RMKS/
1. TROPICAL CYCLONE 26S (TWENTYSIX) WARNING NR 005    
   01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   080000Z --- NEAR 18.0S 106.6E
     MOVEMENT PAST SIX HOURS - 245 DEGREES AT 12 KTS
     POSITION ACCURATE TO WITHIN 030 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            075 NM SOUTHWEST QUADRANT
                            100 NM NORTHWEST QUADRANT
   REPEAT POSIT: 18.0S 106.6E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   081200Z --- 18.4S 104.8E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
080300Z POSITION NEAR 18.1S 106.2E.
08MAR26. TROPICAL CYCLONE 26S (TWENTYSIX), LOCATED APPROXIMATELY
495 NM WEST-NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED WEST-
SOUTHWESTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. ANIMATED 
MULTISPECTRAL SATELLITE IMAGERY (MSI) AND A 072310Z SSMIS 91 GHZ 
IMAGE SHOW REMAINING DEEP CONVECTION CONFINED TO THE WESTERN 
PERIPHERY OF A PARTIALLY EXPOSED LOW-LEVEL CIRCULATION. STRATOCUMULUS 
CLOUD LINES SEEN WRAPPING AROUND THE NORTHERN PERIPHERY OF THE 
CIRCULATION IN MSI TRACE SUSTAINED ENTRAINMENT OF DRIER AIR FROM THE 
SURROUNDING ENVIRONMENT INTO THE EASTERN PORTION OF THE CIRCULATION.   
THE CURRENT POSITION IS SET WITH HIGH CONFIDENCE WITH SUPPORT FROM 
THE 072310Z SSMIS IMAGERY. THE INITIAL INTENSITY IS HEDGED SLIGHTLY 
ABOVE AGENCY SUBJECTIVE DVORAK ESTIMATES (25-30 KTS), CONSISTENT WITH 
CIMSS AUTOMATED INTENSITY ESTIMATES RANGING FROM 32 TO 37 KNOTS. THE 
SYSTEM WILL CONTINUE TO TRACK WEST-SOUTHWESTWARD UNDER THE STEERING 
INFLUENCE OF A SUBTROPICAL RIDGE CENTERED OVER WESTERN AUSTRALIA FOR 
THE NEXT 12 HOURS, DURING WHICH TIME THE CYCLONE IS EXPECTED TO 
DISSIPATE UNDER THE ONGOING INFLUENCE OF SUSTAINED EASTERLY VERTICAL 
WIND SHEAR, ENTRAINMENT OF DRIER AIR, AND PASSAGE OVER MARGINAL SEA 
SURFACE TEMPERATURES (26 TO 27C). THEREFORE, 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 080000Z IS 996 MB. MAXIMUM SIGNIFICANT 
WAVE HEIGHT AT 080000Z IS 13 FEET.//
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WDXS31 PGTW 071500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 26S (TWENTYSIX) WARNING 
NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.6S 108.9E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 407 NM NORTHWEST OF LEARMONTH, AUSTRALIA
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH DEEP
CONVECTION IN THE WESTERN HEMISPHERE BEING SHEARD WESTWARD. THE
LLCC HAS LOST SOME DEFINITION OVER THE LAST 12 HOURS UNDER THE
EFFECTS OF STRONG EASTERLY SHEAR AND DRY AIR ENTRAINMENT. THE
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE
PARTIALLY EXPOSED LLCC IN ANIMATED EIR IMAGERY. THE INITIAL
INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE
HIGH END OF THE AGENCY DVORAK FIXES AND CIMSS INTENSITY ESTIMATES
LISTED BELOW. TC 26S IS NOW ANALYZED TO BE WITHIN AN UNFAVORABLE
ENVIRONMENT CHARACTERIZED BY MODERATE WESTWARD OUTFLOW AND WARM
(27-28 C) SEA SURFACE TEMPERATURES (SST) GREATLY OFFSET BY STRONG
EASTERLY SHEAR AND SIGNIFICANT DRY AIR ENTRAINMENT.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR)
CENTERED OVER WESTERN AUSTRALIA

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   DEMS: T2.0 - 30 KTS
   CIMSS ADT: 33 KTS AT 071130Z
   CIMSS AIDT: 35 KTS AT 071130Z
   CIMSS D-MINT: 25 KTS AT 071157Z
   CIMSS D-PRINT: 26 KTS AT 071130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 25-30 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE WESTWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT FROM THE WEST

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 26S WILL CONTINUE WEST-SOUTHWESTWARD UNDER
THE INFLUENCE OF THE DEEP-LAYER SUBTROPICAL RIDGE TO THE SOUTHEAST.
THE CYCLONE HAS ACCELERATED OVER THE PAST 12 HOURS AND IS EXPECTED
TO APPROACH THE 26 C SST ISOTHERM BY TAU 24. THE COMBINATION OF
COOLER SST, PERSISTENT EASTERLY WIND SHEAR, AND DRY AIR ENTRAINMENT
ARE EXPECTED TO OVERCOME ANY SUPPORT FROM REMAINING WESTWARD
OUTFLOW AND CAUSE DISSIPATION BY TAU 24.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT WITH A 45 NM CROSS-TRACK SPREAD AT TAU 24 AND MINIMAL
ALONG-TRACK SPREAD. NAVGEM REMAINS THE SOUTHERNMOST MODEL WHILE THE
GOOGLE DEEPMIND ENSEMBLE MEAN IS THE NORTHERNMOST. THE JTWC TRACK
FORECAST FOLLOWS CLOSELY TO THE CONSENSUS WITH HIGH CONFIDENCE.
INTENSITY GUIDANCE GENERALLY AGREES ON GRADUAL WEAKENING, WITH ALL
MODELS EXCEPT DECAY SHIPS SUGGESTING DECAY BELOW 35 KNOTS WITHIN
THE NEXT 24 HOURS. THE JTWC INTENSITY FORECAST FOLLOWS CLOSELY TO
THE CONSENSUS WITH HIGH CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: HIGH//
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