Tropical Cyclones [Index]

Tropical Cyclone ZAKA [Southern Hemisphere Summary][Summaries and Track Data]

WTPS21 PGTW 20110206 05:30z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 22.2S 173.3W TO 27.5S 177.8E
WITHIN THE NEXT 12 TO 24 HOURS.  AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 25 TO 30 KNOTS. METSAT IM-
AGERY AT 060000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 22.8S 174.2W. THE SYSTEM IS MOVING WEST-SOUTHWESTWARD AT 09
KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 22.6S
173.3W, IS NOW LOCATED NEAR 22.8S 174.2W, APPROXIMATELY 560 NM EAST-
SOUTHEAST OF NADI, FIJI. ANIMATED MULTISPECTRAL IMAGERY SHOWS A WELL-
DEFINED LOW LEVEL CIRCULATION CENTER (LLCC) WITH GOOD RADIAL
OUTFLOW. ALTHOUGH, INFRARED SATELLITE IMAGERY INDICATES THE
CONVECTION IS STILL SOMEWHAT SHALLOW, A 060126Z AMSRE MICROWAVE
IMAGE DEPICTS IMPROVED CONVECTION WRAPPING AROUND THE LLCC. UPPER
LEVEL ANALYSIS INDICATES A WEAK RIDGE HAS BUILT OVER THE LLCC,
HOWEVER, UPPER LEVEL LOWS ARE ANALYZED TO THE NORTH AND SOUTH OF THE
SYSTEM. ADDITIONALLY, A 051600Z AMSU RADIAL HEIGHT CROSS SECTION
HINTS AT A DEVELOPING WARM CORE WITH A SMALL WARM ANOMALY CENTERED
AT AROUND 40K FEET. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT
25 TO 30 KNOTSS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR
1002 MB.DUE TO THE SEVERAL FACTORS NOW INDICATING THE DISTURBANCE IS
TRANSITIONING INTO A WARM CORE CYCLONE AND DUE TO THE IMPROVED
CONVECTIVE SIGNATURE, THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS GOOD.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
070530Z.//
=========================================================================
WTPS31 PGTW 20110206 21:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 12P (ZAKA) WARNING NR 001//
REF/A/NAVMARFCSTCEN PEARL HARBOR HI/060521Z FEB 11//
AMPN/ REF A IS A TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. TROPICAL CYCLONE 12P (ZAKA) WARNING NR 001    
   01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   061800Z --- NEAR 25.4S 177.3W
     MOVEMENT PAST SIX HOURS - 230 DEGREES AT 13 KTS
     POSITION ACCURATE TO WITHIN 060 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   REPEAT POSIT: 25.4S 177.3W
    ---
   FORECASTS:
   12 HRS, VALID AT:
   070600Z --- 28.5S 179.5W
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 195 DEG/ 18 KTS
    ---
   24 HRS, VALID AT:
   071800Z --- 32.0S 179.3E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 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
                            055 NM SOUTHEAST QUADRANT
                            055 NM SOUTHWEST QUADRANT
                            045 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 180 DEG/ 20 KTS
    ---
   36 HRS, VALID AT:
   080600Z --- 35.9S 179.4E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
062100Z POSITION NEAR 26.2S 177.8W.
TROPICAL CYCLONE (TC) 12P (ZAKA), LOCATED APPROXIMATELY 800 NM
NORTH-NORTHEAST OF AUCKLAND, NEW ZEALAND, HAS TRACKED 
SOUTHWESTWARD AT 13 KNOTS DURING THE PAST 06 HOURS. THIS IS 
THE FIRST WARNING FOR TC ZAKA. ORIGINALLY A SUBTROPICAL CYCLONE 
ZAKA HAS TRANSITIONED INTO A TC WITHIN THE PAST 06 TO 12 HOURS. 
IN ADDITION TO THE TC DEVELOPING A MORE CLASSIC TROPICAL 
SIGNATURE IN VISIBLE SATELLITE IMAGERY, A 060900Z ASMSU RADIAL 
CROSS SECTION PRODUCED BY CIRA (RAMMB) QUANTITATIVELY SUPPORTS 
TROPICAL TRANSITION. GIVEN THE SHALLOW NATURE OF THE CENTRAL 
CONVECTION, AND THE SYSTEM'S RECENT TRANSITION TO A WARM CORE TC, 
DVORAK INTENSITY ESTIMATES VARY SIGNIFICANTLY AMONG THE FOUR 
FIXING AGENCIES. THE INITIAL FORECAST INTENSITY OF 45 KNOTS 
FAVORS THE LOWER END OF THE DVORAK SPREAD BECAUSE OF PERSISTENCE 
AND THE LACK OF DEEP CENTRAL CONVECTION. THE SYSTEM WILL BEGIN TO 
TURN POLEWARD OVER THE NEXT 12 HOURS AS THE MID-LEVEL STEERING 
RIDGE TO THE SOUTHEAST BEGINS TO ERODE IN ADVANCE OF A PASSING 
LONGWAVE TROUGH IN THE MID-LATITUDES. THE SYSTEM WILL WEAKEN 
BELOW 35 KNOTS BEFORE RECURVING INTO THE WESTERLIES DUE TO A DROP 
IN SEA SURFACE TEMPERATURES AND AN INCREASE IN VERTICAL WIND SHEAR. 
THIS FORECAST CLOSELY FOLLOWS THE MODEL CONSENSUS DUE TO SIMILAR 
SOLUTIONS AMONG THE MEMBERS. THIS WARNING SUPERSEDES AND CANCELS 
REF A, NAVMARFCSTCEN 060530Z FEB 11 TROPICAL CYCLONE FORMATION 
ALERT (WTPS21 PGTW 060530). MAXIMUM SIGNIFICANT WAVE HEIGHT AT 
061800Z IS 14 FEET. NEXT WARNINGS AT 070900Z AND 072100Z.//
=========================================================================
WTPS31 PGTW 20110207 09:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 12P (ZAKA) WARNING NR 002//
RMKS/
1. TROPICAL CYCLONE 12P (ZAKA) WARNING NR 002
   01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   070600Z --- NEAR 29.3S 179.3W
     MOVEMENT PAST SIX HOURS - 205 DEGREES AT 22 KTS
     POSITION ACCURATE TO WITHIN 060 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
                            070 NM SOUTHEAST QUADRANT
                            065 NM SOUTHWEST QUADRANT
                            060 NM NORTHWEST QUADRANT
   REPEAT POSIT: 29.3S 179.3W
    ---
   FORECASTS:
   12 HRS, VALID AT:
   071800Z --- 33.3S 180.0E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   VECTOR TO 24 HR POSIT: 170 DEG/ 20 KTS
    ---
   24 HRS, VALID AT:
   080600Z --- 37.2S 179.2W
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
070900Z POSITION NEAR 30.3S 179.5W.
TROPICAL CYCLONE (TC) 12P (ZAKA), LOCATED APPROXIMATELY 550 NM
NORTHEAST OF AUCKLAND, NEW ZEALAND, HAS TRACKED SOUTH-SOUTHWESTWARD
AT 22 KNOTS DURING THE PAST 06 HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY (MSI) SHOWS A WELL-DEFINED LOW LEVEL CIRCULATION
CENTER (LLCC) WITH THE MAJORITY OF THE CONVECTION WRAPPING AROUND
THE EASTERN PERIPHERY. THE SYSTEM APPEARS TO HAVE WEAKENED WITHIN
THE PAST 12 HOURS BASED ON THE TREND IN MICROWAVE IMAGERY. A 070208Z
AMSRE MICROWAVE IMAGE DEPICTS A DECREASE IN DEEP CONVECTIVE BANDING.
THE INITIAL POSITION WAS BASED ON THE MSI IMAGERY WITH FAIR
CONFIDENCE. THE INITIAL INTENSITY WAS SLIGHTLY HIGHER THAN THE PGTW
DVORAK ESTIMATE OF 35 KNOTS. AN UPPER LEVEL LOW TO THE NORTHWEST
APPEARS TO BE SUPPRESSING CONVECTION ON THAT SIDE. THE SYSTEM WILL
CONTINUE TO TURN POLEWARD AS THE MID-LEVEL STEERING RIDGE TO THE
SOUTHEAST BEGINS TO ERODE IN ADVANCE OF A PASSING LONGWAVE TROUGH IN
THE MID-LATITUDES. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT,
THEREFORE THERE IS HIGH CONFIDENCE IN THIS TRACK FORECAST.  TC 12P
IS EXPECTED TO WEAKEN BELOW 35 KNOTS WITHIN 24 HOURS DUE TO THE
SUBSIDENCE THE NORTHWEST, INCREASED VERTICAL WIND SHEAR
ASSOCIATED WITH THE MID-LATITUDE TROUGH, AND UNFAVORABLE SEA SURFACE
TEMPERATURES. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 070600Z IS 14 FEET.
NEXT WARNINGS AT 072100Z.//
=========================================================================
WTPS31 PGTW 20110207 21:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 12P (ZAKA) WARNING NR 003//
RMKS/
1. TROPICAL CYCLONE 12P (ZAKA) WARNING NR 003
   01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   071800Z --- NEAR 32.3S 179.8E
     MOVEMENT PAST SIX HOURS - 175 DEGREES AT 18 KTS
     POSITION ACCURATE TO WITHIN 060 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
   REPEAT POSIT: 32.3S 179.8E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   080600Z --- 36.9S 178.6W
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
072100Z POSITION NEAR 33.5S 179.8W.
TROPICAL CYCLONE (TC) 12P (ZAKA), LOCATED APPROXIMATELY 380 NM
NORTHEAST OF AUCKLAND, NEW ZEALAND, HAS TRACKED SOUTHWARD AT 18
KNOTS DURING THE PAST 06 HOURS. ANIMATED INFRARED SATELLITE
IMAGERY SHOWS THE SYSTEM RAPIDLY DISSIPATING OVER WATER.
A 071639Z TRMM IMAGE REVEALS CORE CONVECTION HAS ALMOST COMPLETELY
DISSIPATED AND THE LOW LEVEL CIRCULATION CENTER IS RAPIDLY BECOMING
CLOUD-FREE. 12P IS NOW TURNING INTO THE MID-LATITUDES, WHERE IT WILL
CONTINUING DECAYING UNDER THE EFFECTS OF INCREASING VERTICAL
WIND SHEAR AND DECREASING SEA SURFACE TEMPERATURES. THIS IS THE
FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WARNING CENTER
(NAVMARFCSTCEN). THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF
REGENERATION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 071800Z IS 14 FEET.