Tropical Cyclones [Index]

Tropical Cyclone ALFRED Southern Hemisphere Summary

WTPS31 PGTW 20170220 03:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 06P (ALFRED) WARNING NR 001//
RMKS/
1. TROPICAL CYCLONE 06P (ALFRED) 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:
   200000Z --- NEAR 15.2S 137.1E
     MOVEMENT PAST SIX HOURS - 110 DEGREES AT 03 KTS
     POSITION ACCURATE TO WITHIN 025 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 - 050 NM NORTHEAST QUADRANT
                            045 NM SOUTHEAST QUADRANT
                            040 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   REPEAT POSIT: 15.2S 137.1E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   201200Z --- 15.5S 137.2E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 180 DEG/ 02 KTS
    ---
   24 HRS, VALID AT:
   210000Z --- 15.9S 137.2E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
                            045 NM SOUTHEAST QUADRANT
                            040 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 200 DEG/ 02 KTS
    ---
   36 HRS, VALID AT:
   211200Z --- 16.2S 137.1E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   VECTOR TO 48 HR POSIT: 275 DEG/ 07 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   220000Z --- 16.1S 135.7E
   MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
200300Z POSITION NEAR 15.3S 137.1E.
TROPICAL CYCLONE 06P (ALFRED), LOCATED APPROXIMATELY 396 NM EAST-
SOUTHEAST OF DARWIN, AUSTRALIA, HAS TRACKED EAST-SOUTHEASTWARD AT
03 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS FLARING CENTRAL CONVECTION WITH WEAK FRAGMENTED
BANDING TO THE EAST WRAPPING INTO THE LOW LEVEL CIRCULATION CENTER
(LLCC). THE INITIAL POSITION IS BASED ON AN EDGE OF SWATH 200029Z
METOP-B ASCAT IMAGE SHOWING THE LLCC A BIT FURTHER OFFSHORE THAN THE
FLARING CONVECTION OBSERVED IN SATELLITE IMAGERY SUGGESTS,
INDICATING SOME SOUTHERLY WIND SHEAR PRESENT OVER THE SYSTEM. THE
INITIAL INTENSITY ASSESSMENT OF 40 KNOTS IS BASED ON SURFACE
OBSERVATIONS FROM CENTRE ISLAND WHERE SUBJECTIVE DVORAK ESTIMATES
HAVE LAGGED BEHIND. ENVIRONMENTAL CONDITIONS ARE CURRENTLY VERY
FAVORABLE AS AN UPPER-LEVEL TROUGH IS MOVING IN FROM THE WEST
PROVIDING AN EXCELLENT POLEWARD OUTFLOW CHANNEL AND SSTS IN THE GULF
OF CARPENTARIA ARE EXTREMELY WARM NEAR 31 CELSIUS. CURRENTLY TC
ALFRED IS IN A WEAK STEERING ENVIRONMENT DRIFTING EAST-SOUTHEASTWARD
OVER THE LAST 12 HOURS. A DEEP-LAYERED SUBTROPICAL RIDGE IS BUILDING
TO THE EAST AND WILL STEER TC ALFRED SLOWLY TO THE SOUTH OVER THE
NEXT 24 HOURS. THERE IS A LIMITED OPPORTUNITY FOR THE SYSTEM TO
INTENSIFY FURTHER IN THE NEXT 12 HOURS TO 45 KNOTS BEFORE THE TROUGH
MOVES THROUGH BRINGING HIGHER WIND SHEAR OVER THE SYSTEM. HOWEVER,
THE SYSTEM'S PROXIMITY TO LAND WILL ALSO HINDER FURTHER DEVELOPMENT
OVER THE FORECAST PERIOD. BEYOND TAU 36 ANOTHER SUBTROPICAL RIDGE
EXTENSION WILL BUILD IN FROM THE SOUTH ACCELERATING TC ALFRED TO THE
WEST. THE SYSTEM IS FORECAST TO FULLY DISSIPATE OVER LAND BY TAU 48.
DYNAMIC MODEL GUIDANCE IS IN POOR AGREEMENT OVER THE NEXT 36 HOURS
WHILE THE SYSTEM IS IN A WEAK STEERING ENVIRONMENT. MOST SOLUTIONS
SUGGEST A GENERAL SOUTHWARD TRACK FOLLOWED BY AN ACCELERATED
WESTWARD TRACK. DUE TO THE POSITION OF THE SYSTEM AND TIMING OF THE
BUILDING SOUTHERN RIDGE THERE IS A LARGE DEGREE OF UNCERTAINTY.
OVERALL THERE IS LOW CONFIDENCE IN THE FORECAST TRACK.  MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 200000Z IS 12 FEET. NEXT WARNINGS AT
201500Z AND 210300Z.//
=========================================================================
WTPS31 PGTW 20170220 15:00z
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 06P (ALFRED) WARNING NR 002//
RMKS/
1. TROPICAL CYCLONE 06P (ALFRED) 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:
   201200Z --- NEAR 16.3S 137.5E
     MOVEMENT PAST SIX HOURS - 175 DEGREES AT 08 KTS
     POSITION ACCURATE TO WITHIN 025 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
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
                            045 NM SOUTHEAST QUADRANT
                            040 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   REPEAT POSIT: 16.3S 137.5E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   210000Z --- 16.8S 137.4E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
   RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 225 DEG/ 03 KTS
    ---
   24 HRS, VALID AT:
   211200Z --- 17.2S 137.0E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND
    ---
REMARKS:
201500Z POSITION NEAR 16.4S 137.5E.
TROPICAL CYCLONE 06P (ALFRED), LOCATED APPROXIMATELY 446 NM EAST-
SOUTHEAST OF DARWIN, AUSTRALIA, HAS TRACKED SOUTHWARD AT 08 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS A RAPIDLY DETERIORATING SYSTEM THAT HAS JUST MADE
LANDFALL WITH LIMITED ASSOCIATED CONVECTION. THE INITIAL POSITION IS
PLACED WITH GOOD CONFIDENCE AND IS BASED ON RECENT SATELLITE FIXES
AND A 200935Z 91 GHZ SSMIS IMAGE SHOWING THE LLCC MOVING
SIGNIFICANTLY SOUTHWARD TOWARD THE COASTLINE OVER THE LAST SIX
HOURS. THE INITIAL INTENSITY ASSESSMENT OF 40 KNOTS IS SUPPORTED BY
LOCAL SURFACE OBSERVATIONS IN THE VICINITY OF THE SYSTEM. CURRENTLY
A BUILDING DEEP-LAYERED SUBTROPICAL RIDGE TO THE EAST IS STEERING
THE SYSTEM ON A SOUTHWARD COURSE. THE REMNANTS OF TC ALFRED IS
EXPECTED TO TRACK FURTHER INLAND AND DISSIPATE BY TAU 24. MODEL
GUIDANCE IS IN POOR AGREEMENT WITH THE EXACT DIRECTION OF TRACK
MOVEMENT OVER THE NEXT 24 HOURS AS THE SYSTEM WEAKENS, HOWEVER EACH
AVAILABLE SOLUTION SHOWS A TRACK PENETRATING FURTHER INLAND. OVERALL
THERE IS LOW CONFIDENCE IN THE FORECAST TRACK. 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 201200Z IS 9 FEET.//