簽到天數: 1650 天 [LV.Master]伴壇終老
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老農民版夜神月|2021-3-1 11:28
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JTWC首報上望70節不封頂
REMARKS:
010300Z POSITION NEAR 17.0S 147.2E.
01MAR21. TROPICAL CYCLONE (TC) 23P (TWENTYTHREE), LOCATED
APPROXIMATELY 82 NM EAST-SOUTHEAST OF CAIRNS, AUSTRALIA, HAS
TRACKED WESTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY DEPICTS A PARTIALLY-EXPOSED, WELL-
DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC) POSITIONED ALONG THE
EASTERN EDGE OF A LARGE CLUSTER OF PERSISTENT DEEP CONVECTION.
DESPITE MODERATE TO STRONG (20-25 KNOT) NORTHEASTERLY VERTICAL WIND
SHEAR (VWS), THERE IS GOOD EVIDENCE THAT THE SYSTEM HAS CONSOLIDATED
OVER THE PAST TWELVE HOURS: FIRST, A 282030Z MHS 89GHZ MICROWAVE
IMAGE REVEALS MULTIPLE SHALLOW BANDS WRAPPING TIGHTLY INTO A DEFINED
LLCC; SECOND, SURFACE OBSERVATIONS FROM LUCINDA AND HOLMES REEF
INDICATE PEAK SUSTAINED WINDS OF 35-40 KNOTS (1-MINUTE AVERAGE);
THIRD, FLINDER'S REEF REPORTED MINIMUM SLP OF 996MB, WHICH
CORRESPONDS TO A 35 KNOT SYSTEM, WITH A SIGNIFICANT 4-5MB 24-HOUR
SLP DECREASE. DVORAK ESTIMATES ALSO SUPPORT THE 35-KNOT INTENSITY
ASSESSMENT AND RANGE FROM T2.0 (30 KNOTS) TO T2.5 (35 KNOTS).
ENVIRONMENTAL ANALYSIS DEPICTS A MARGINAL ENVIRONMENT WITH THE
MODERATE TO STRONG VWS OFFSET BY ROBUST POLEWARD OUTFLOW AND WARM
SST VALUES (30C). THE CURRENT STEERING ENVIRONMENT IS VERY COMPLEX
WITH A STRONG SUBTROPICAL RIDGE (STR) OVER EASTERN AUSTRALIA AND
ANOTHER STR EAST AND SOUTH OF THE SYSTEM. ADDITIONALLY, A STRONG
NEAR-EQUATORIAL RIDGE IS ENTRENCHED NORTH OF THE SYSTEM.
CONSEQUENTLY, TC 23P IS BOXED IN AND THE TRACK MOTION IS EXPECTED TO
BE SLOW, LIMITED AND ERRATIC THROUGH TAU 72 DUE TO A COMBINATION OF
THESE STEERING INFLUENCES. THE JTWC FORECAST TRACK INDICATES A
CLOCKWISE LOOP WHICH IS IN LINE WITH THE BULK OF THE NUMERICAL MODEL
GUIDANCE THROUGH TAU 72. THERE IS OBVIOUSLY HIGH UNCERTAINTY (LOW
CONFIDENCE) IN THE TRACK DUE TO THE AFOREMENTIONED COMPLEX STEERING
ENVIRONMENT. VWS WILL DECREASE THUS THE SYSTEM IS FORECAST TO
GRADUALLY INTENSIFY THROUGH TAU 72. AFTER TAU 72, A MAJOR
MIDLATITUDE TROUGH IS FORECAST TO DEEPEN TO THE SOUTH, WHICH WILL
ERODE THE STR AND ALLOW THE SYSTEM TO ACCELERATE EAST-SOUTHEASTWARD
ALONG THE SOUTHERN PERIPHERY OF THE NEAR-EQUATORIAL RIDGE THROUGH
THE REMAINDER OF THE PERIOD. THIS TROUGH WILL ALSO IMPROVE POLEWARD
VENTING WHICH WILL LEAD TO A SHARPER INTENSIFICATION RATE WITH A
PEAK INTENSITY OF 70 KNOTS ANTICIPATED BY TAU 120. OVERALL, THERE IS
LOW CONFIDENCE IN THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 010000Z IS 14 FEET. NEXT WARNINGS AT 010900Z, 011500Z,
012100Z AND 020300Z.
2. THIS CANCELS AND SUPERSEDES REF A (WTPS21 PGTW 281300).//
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