WARNING 18/JTWC
https://www.facebook.com/groups/1817419381676514/
Location: 20.1°S 117.5°E
Maximum Winds: 115 kt ( 215km/h)
Gusts: 140 kt (260km/h)
Minimum Central Pressure: 938 mb
CATEGORY 4 US
REMARKS:
240300Z POSITION NEAR 20.2S 117.5E.
TROPICAL CYCLONE (TC) 21S (VERONICA), LOCATED APPROXIMATELY 231 NM
NORTHEAST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWARD AT 03
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS A CONSOLIDATING SYSTEM WITH TIGHTLY-CURVED
BANDING WRAPPING INTO A 15-20NM IRREGULAR EYE, WHICH SUPPORTS THE
INITIAL POSITION WITH GOOD CONFIDENCE. DESPITE DRY AIR ENTRAINING
AROUND THE PERIPHERY OF THE SYSTEM AND ERODING DEEP CONVECTIVE
BANDING, BOTH RADAR IMAGERY AND TOTAL PRECIPITABLE WATER VAPOR
IMAGERY INDICATE THAT THE SYSTEM HAS BEEN ABLE TO MAINTAIN A MOIST
CORE AND THE EYEWALL CONVECTION. ADDITIONALLY, THE CORE HAS REMAINED
OVER WATER AND THE TERRAIN OVER THIS COASTAL REGION IS RELATIVELY
FLAT AND MOIST. CONSEQUENTLY, DVORAK INTENSITY ESTIMATES HAVE
INCREASED AND CURRENTLY RANGE FROM T5.0 (90 KNOTS) TO T6.0 (115
KNOTS). ADVANCED DVORAK TECHNIQUE ESTIMATES JUMPED BRIEFLY TO 6.2
(ABOUT 118 KNOTS) BUT HAVE DECREASED BACK TO 5.7 (ABOUT 110 KNOTS)
THUS THE INITIAL INTENSITY IS DIFFICULT TO ACCURATELY ASSESS AND IS
CONSERVATIVELY INCREASED TO 115 KNOTS. THE STRONGEST SURFACE WINDS
OCCURRED AT LEGENDRE ISLAND AT 232103Z, ABOUT 40NM WEST-SOUTHWEST OF
THE CENTER, WITH PEAK SUSTAINED WINDS (10-MINUTE AVERAGE) AT 61
KNOTS GUSTING TO 85 KNOTS (NOTE THAT OBSERVATION REPORTS CEASED AT
232230Z LIKELY DUE TO SENSOR PROBLEMS). POLEWARD OUTFLOW REMAINS
ROBUST WITH A STRONG POLEWARD OUTFLOW CHANNEL INTO THE WESTERLIES TO
THE SOUTH AND LOW TO MODERATE VERTICAL WIND SHEAR. TC 21S IS
FORECAST TO TRACK SLOWLY SOUTHWARD THROUGH TAU 12 ALONG THE WESTERN
PERIPHERY OF A WEAK INDUCED STEERING RIDGE, WHICH IS POSITIONED
BETWEEN TC 21S AND TC 20P. AS THE SYSTEM TRACKS CLOSER TO THE
NORTHWEST COAST OF AUSTRALIA AND WEAKENS SIGNIFICANTLY DUE TO LAND
INTERACTION, DRY AIR ENTRAINMENT AND INCREASING VERTICAL WIND SHEAR,
TC 21S IS FORECAST TO SLOW AS A STRONG LOW-LEVEL HIGH BUILDS OVER
SOUTHWESTERN AUSTRALIA WITH THE REMNANTS OF THE SYSTEM EXPECTED TO
TRACK WESTWARD TO WEST-SOUTHWESTWARD. THERE IS A POSSIBILITY THAT
THE REMNANTS MAY TRACK CLOSER TO LEARMONTH, HOWEVER, THERE IS A HIGH
CERTAINTY THAT THE SYSTEM WILL REMAIN A WEAK REMNANT LOW DUE TO THE
PRESENCE OF STRONG UPPER-LEVEL NORTHWESTERLY FLOW PERSISTING OVER
NORTHWEST AUSTRALIA (LEARMONTH SOUNDING CURRENTLY SHOWS WESTERLY
WINDS OF 45 KNOTS NEAR 300MB). OVERALL, THERE IS LOW CONFIDENCE IN
THE JTWC FORECAST TRACK DUE TO UNCERTAINTY IN THE TRACK SPEEDS AND
TIMING OF THE WESTWARD TURN WITH A 206NM SPREAD IN SOLUTIONS AT TAU
72. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 240000Z IS 30 FEET. NEXT
WARNINGS AT 240900Z, 241500Z, 242100Z AND 250300Z. REFER TO TROPICAL
CYCLONE 22S (JOANINHA) WARNINGS (WTXS31 PGTW) FOR SIX-HOURLY
UPDATES.//
NNNN
Location: 20.1°S 117.5°E
Maximum Winds: 115 kt ( 215km/h)
Gusts: 140 kt (260km/h)
Minimum Central Pressure: 938 mb
CATEGORY 4 US
REMARKS:
240300Z POSITION NEAR 20.2S 117.5E.
TROPICAL CYCLONE (TC) 21S (VERONICA), LOCATED APPROXIMATELY 231 NM
NORTHEAST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWARD AT 03
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS A CONSOLIDATING SYSTEM WITH TIGHTLY-CURVED
BANDING WRAPPING INTO A 15-20NM IRREGULAR EYE, WHICH SUPPORTS THE
INITIAL POSITION WITH GOOD CONFIDENCE. DESPITE DRY AIR ENTRAINING
AROUND THE PERIPHERY OF THE SYSTEM AND ERODING DEEP CONVECTIVE
BANDING, BOTH RADAR IMAGERY AND TOTAL PRECIPITABLE WATER VAPOR
IMAGERY INDICATE THAT THE SYSTEM HAS BEEN ABLE TO MAINTAIN A MOIST
CORE AND THE EYEWALL CONVECTION. ADDITIONALLY, THE CORE HAS REMAINED
OVER WATER AND THE TERRAIN OVER THIS COASTAL REGION IS RELATIVELY
FLAT AND MOIST. CONSEQUENTLY, DVORAK INTENSITY ESTIMATES HAVE
INCREASED AND CURRENTLY RANGE FROM T5.0 (90 KNOTS) TO T6.0 (115
KNOTS). ADVANCED DVORAK TECHNIQUE ESTIMATES JUMPED BRIEFLY TO 6.2
(ABOUT 118 KNOTS) BUT HAVE DECREASED BACK TO 5.7 (ABOUT 110 KNOTS)
THUS THE INITIAL INTENSITY IS DIFFICULT TO ACCURATELY ASSESS AND IS
CONSERVATIVELY INCREASED TO 115 KNOTS. THE STRONGEST SURFACE WINDS
OCCURRED AT LEGENDRE ISLAND AT 232103Z, ABOUT 40NM WEST-SOUTHWEST OF
THE CENTER, WITH PEAK SUSTAINED WINDS (10-MINUTE AVERAGE) AT 61
KNOTS GUSTING TO 85 KNOTS (NOTE THAT OBSERVATION REPORTS CEASED AT
232230Z LIKELY DUE TO SENSOR PROBLEMS). POLEWARD OUTFLOW REMAINS
ROBUST WITH A STRONG POLEWARD OUTFLOW CHANNEL INTO THE WESTERLIES TO
THE SOUTH AND LOW TO MODERATE VERTICAL WIND SHEAR. TC 21S IS
FORECAST TO TRACK SLOWLY SOUTHWARD THROUGH TAU 12 ALONG THE WESTERN
PERIPHERY OF A WEAK INDUCED STEERING RIDGE, WHICH IS POSITIONED
BETWEEN TC 21S AND TC 20P. AS THE SYSTEM TRACKS CLOSER TO THE
NORTHWEST COAST OF AUSTRALIA AND WEAKENS SIGNIFICANTLY DUE TO LAND
INTERACTION, DRY AIR ENTRAINMENT AND INCREASING VERTICAL WIND SHEAR,
TC 21S IS FORECAST TO SLOW AS A STRONG LOW-LEVEL HIGH BUILDS OVER
SOUTHWESTERN AUSTRALIA WITH THE REMNANTS OF THE SYSTEM EXPECTED TO
TRACK WESTWARD TO WEST-SOUTHWESTWARD. THERE IS A POSSIBILITY THAT
THE REMNANTS MAY TRACK CLOSER TO LEARMONTH, HOWEVER, THERE IS A HIGH
CERTAINTY THAT THE SYSTEM WILL REMAIN A WEAK REMNANT LOW DUE TO THE
PRESENCE OF STRONG UPPER-LEVEL NORTHWESTERLY FLOW PERSISTING OVER
NORTHWEST AUSTRALIA (LEARMONTH SOUNDING CURRENTLY SHOWS WESTERLY
WINDS OF 45 KNOTS NEAR 300MB). OVERALL, THERE IS LOW CONFIDENCE IN
THE JTWC FORECAST TRACK DUE TO UNCERTAINTY IN THE TRACK SPEEDS AND
TIMING OF THE WESTWARD TURN WITH A 206NM SPREAD IN SOLUTIONS AT TAU
72. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 240000Z IS 30 FEET. NEXT
WARNINGS AT 240900Z, 241500Z, 242100Z AND 250300Z. REFER TO TROPICAL
CYCLONE 22S (JOANINHA) WARNINGS (WTXS31 PGTW) FOR SIX-HOURLY
UPDATES.//
NNNN
WARNING 18/JTWC
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