Tropical Cyclones [Index]

Tropical Cyclone 201714 Southern Hemisphere Summary

WTPS21 PGTW 20170405 01:30z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
125 NM EITHER SIDE OF A LINE FROM 19.4S 170.1W TO 22.6S 170.6W
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
IMAGERY AT 040000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 19.4S 170.1W. THE SYSTEM IS MOVING SOUTH-SOUTHWESTWARD AT 04
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 93P) PREVIOUSLY LOCATED
NEAR 18.6S 169.7W, IS NOW LOCATED NEAR 19.4S 170.1W, APPROXIMATELY
300 NM NORTHEAST OF TONGA. ANIMATED MULTI-SPECTRAL SATELLITE IMAGERY
AND A 042056Z METOP-B 89 GHZ MICROWAVE IMAGE SHOWS CURVED CONVECTIVE
BANDING WRAPPING INTO A DEVELOPING LOW-LEVEL CIRCULATION CENTER
(LLCC). A 042058Z ASCAT METOP-B PASS SHOWS 25-30 KNOT WINDS
ALONG THE EASTERN PERIPHERY WRAPPING INTO THE LLCC. THE DISTURBANCE
IS CURRENTLY LOCATED IN A FAVORABLE ENVIRONMENT WITH EXCELLENT
POLEWARD OUTFLOW, MODERATE VERTICAL WIND SHEAR (15-20 KNOTS), AND
WARM SEA SURFACE TEMPERATURES (28-29 C). MODEL GUIDANCE INDICATES
THE DEVELOPMENT OF A TROPICAL CYCLONE IS LIKELY WITHIN THE NEXT 12
TO 24 HOURS AS THIS DISTURBANCE TRACKS SOUTH-SOUTHWESTWARD. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. BASED ON IMPROVED
STRUCTURE AND FAVORABLE ENVIRONMENTAL CONDITIONS, THE POTENTIAL FOR
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
060130Z.//
=========================================================================
WTPS31 PGTW 20170405 15:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 14P (FOURTEEN) WARNING NR 001//
RMKS/
1. TROPICAL CYCLONE 14P (FOURTEEN) 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:
   051200Z --- NEAR 20.1S 171.1W
     MOVEMENT PAST SIX HOURS - 240 DEGREES AT 06 KTS
     POSITION ACCURATE TO WITHIN 025 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
   RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT
                            095 NM SOUTHEAST QUADRANT
                            000 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   REPEAT POSIT: 20.1S 171.1W
    ---
   FORECASTS:
   12 HRS, VALID AT:
   060000Z --- 20.4S 172.0W
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 125 NM NORTHEAST QUADRANT
                            100 NM SOUTHEAST QUADRANT
                            040 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 265 DEG/ 04 KTS
    ---
   24 HRS, VALID AT:
   061200Z --- 20.5S 172.9W
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
                            150 NM SOUTHEAST QUADRANT
                            055 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 245 DEG/ 03 KTS
    ---
   36 HRS, VALID AT:
   070000Z --- 20.7S 173.4W
   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 - 035 NM NORTHEAST QUADRANT
                            145 NM SOUTHEAST QUADRANT
                            030 NM SOUTHWEST QUADRANT
                            010 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 205 DEG/ 02 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   071200Z --- 21.1S 173.6W
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
051500Z POSITION NEAR 20.2S 171.3W.
TROPICAL CYCLONE (TC) 14P (FOURTEEN), LOCATED APPROXIMATELY 91 NM
SOUTHWEST OF NIUE, HAS TRACKED WEST-SOUTHWESTWARD AT 06 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY AND A 050925Z AMSU 89 GHZ MICROWAVE IMAGE DEPICT A DEFINED
BUT PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER WITH FLARING,
DEEP CONVECTION ALONG THE EASTERN SEMICIRCLE, AND SUPPORTS THE
CURRENT JTWC BEST TRACK POSITION WITH HIGH CONFIDENCE. THE INITIAL
INTENSITY OF 35 KNOTS IS ABOVE MULTI-AGENCY DVORAK CURRENT
INTENSITIES OF T1.5 (25 KNOTS) AND IS SUPPORTED BY A 050927Z ASCAT
PASS REVEALING 35 KNOT WINDS BEGINNING TO WRAP IN ALONG THE
SOUTHEAST PERIPHERY. ENVIRONMENTAL CONDITIONS ARE SLIGHTLY FAVORABLE
FOR DEVELOPMENT WITH GOOD POLEWARD OUTFLOW AND 28C SSTS, HOWEVER
VERTICAL WIND SHEAR (VWS) VALUES REMAIN MODERATE-STRONG (20 TO 25
KNOTS). TC 14P IS TRACKING WEST-SOUTHWESTWARD ALONG THE NORTHERN
PERIPHERY OF AN ELONGATED STR TO THE SOUTH. THIS SYSTEM IS FORECAST
TO REMAIN UNDER THIS STEERING INFLUENCE OVER THE NEXT 24 HOURS. THE
CYCLONE MAY HAVE A SHORT WINDOW OF WEAK INTENSIFICATION WHILE
OUTFLOW AND SSTS REMAIN SUPPORTIVE DURING THIS PERIOD. HOWEVER,
BEYOND TAU 24, AN APPROACHING TROUGH FROM THE WEST WILL BEGIN TO
RECURVE TC 14P SHARPLY SOUTHWARD INTO AN AREA OF STRONGER VWS AND
COLDER SSTS RESULTING IN FULL DISSIPATION OF THE SYSTEM BY TAU 48.
DYNAMIC MODEL GUIDANCE SHOW HIGH UNCERTAINTY REGARDING THE UPPER-
LEVEL STEERING PATTERN LENDING LOW CONFIDENCE TO THE JTWC FORECAST
TRACK AT THIS TIME. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 051200Z IS 12
FEET. NEXT WARNINGS AT 060300Z AND 061500Z.//
=========================================================================
WTPS31 PGTW 20170406 03:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 14P (FOURTEEN) WARNING NR 002//
RMKS/
1. TROPICAL CYCLONE 14P (FOURTEEN) 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:
   060000Z --- NEAR 20.4S 170.4W
     MOVEMENT PAST SIX HOURS - 120 DEGREES AT 02 KTS
     POSITION ACCURATE TO WITHIN 020 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
   RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT
                            095 NM SOUTHEAST QUADRANT
                            040 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   REPEAT POSIT: 20.4S 170.4W
    ---
   FORECASTS:
   12 HRS, VALID AT:
   061200Z --- 20.7S 170.2W
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT
                            095 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 165 DEG/ 02 KTS
    ---
   24 HRS, VALID AT:
   070000Z --- 21.0S 170.1W
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT
                            085 NM SOUTHEAST QUADRANT
                            055 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 180 DEG/ 01 KTS
    ---
   36 HRS, VALID AT:
   071200Z --- 21.3S 170.1W
   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 - 025 NM NORTHEAST QUADRANT
                            045 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 225 DEG/ 03 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   080000Z --- 21.7S 170.5W
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
060300Z POSITION NEAR 20.5S 170.4W.
TROPICAL CYCLONE 14P (FOURTEEN), LOCATED APPROXIMATELY 366 NM
SOUTH OF PAGO PAGO, HAS TRACKED EAST-SOUTHEASTWARD AT 02 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER
WITH PERSISTENT CENTRAL CONVECTION BEING SHEARED TO THE EAST.
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE
EXPOSED LLCC. THE INITIAL INTENSITY ASSESSMENT OF 35 KNOTS IS HEDGED
SLIGHTLY HIGHER THAN CURRENT INTENSITY SUBJECTIVE DVORAK ESTIMATES
OF T2.0 (30 KNOTS), AND IS BASED ON A 050924Z METOP-B ASCAT PASS
SHOWING 35 KNOT WINDS. ENVIRONMENTAL CONDITIONS ARE CURRENTLY
MARGINAL WITH SSTS NEAR 28 CELSIUS AND GOOD DIVERGENCE ON THE
EASTERN PERIPHERY BEING OFFSET BY HIGH (25 TO 30 KNOTS) VERTICAL
WIND SHEAR. FURTHER INTENSIFICATION TO 40 KNOTS IS EXPECTED IN THE
NEXT 12 TO 24 HOURS AS DIVERGENCE REMAINS FAVORABLE. BEYOND TAU 24
WIND SHEAR IS EXPECTED TO INCREASE AND THE SYSTEM WILL DISSIPATE BY
TAU 48. CURRENTLY THE SYSTEM IS TRACKING SLOWLY SOUTHEASTWARD BY TWO
MID TO LOW LEVEL RIDGES, ONE TO THE NORTHEAST, AND THE OTHER TO THE
SOUTH RESULTING IN A SLOW FORECAST TRACK THAT IS EXPECTED TO SHIFT
SLIGHTLY SOUTHWESTWARD. DYNAMIC MODEL GUIDANCE SHOWS SIGNIFICANT
SPREAD IN TRACK SOLUTIONS DUE TO THE TWO COMPETING RIDGES. DUE TO
THE MODEL UNCERTAINTY THERE IS LOW CONFIDENCE IN THE FORECAST TRACK.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 060000Z IS 9 FEET. NEXT
WARNINGS AT 061500Z AND 070300Z.//
=========================================================================
WTPS31 PGTW 20170406 15:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 14P (FOURTEEN) WARNING NR 003//
RMKS/
1. TROPICAL CYCLONE 14P (FOURTEEN) 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:
   061200Z --- NEAR 20.8S 169.8W
     MOVEMENT PAST SIX HOURS - 125 DEGREES AT 03 KTS
     POSITION ACCURATE TO WITHIN 020 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: 20.8S 169.8W
    ---
   FORECASTS:
   12 HRS, VALID AT:
   070000Z --- 21.3S 169.6W
   MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
061500Z POSITION NEAR 20.9S 169.8W.
TROPICAL CYCLONE (TC) 14P (FOURTEEN), LOCATED APPROXIMATELY 102 NM
SOUTH OF NIUE, HAS TRACKED SOUTHEASTWARD AT 03 KNOTS OVER THE PAST
SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS
THE ASSOCIATED CONVECTION HAS SIGNIFICANTLY SHEARED EASTWARD OF THE
LOW LEVEL CIRCULATION THAT HAS BECOME UNRAVELED. THE INITIAL POSITION
IS BASED ON THE EIR LOOP AND ON THE 060905Z AMSU MICROWAVE PASS WITH
LOW CONFIDENCE. THE INITIAL INTENSITY IS BASED ON AN OVERALL
ASSESSMENT OF AVAILABLE OBJECTIVE AND AGENCY DVORAK ESTIMATES. UPPER
LEVEL ANALYSIS INDICATES THE CYCLONE HAS DRIFTED INTO AN AREA OF
STRONG (30-40 KNOT) VERTICAL WIND SHEAR. TC 14P HAS WEAKENED TO BELOW
JTWC WARNING CRITERIA. 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. MAXIMUM SIGNIFICANT WAVE HEIGHT
AT 061200Z IS 8 FEET.//