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krichard2011|2016-4-15 19:47
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顯示全部樓層
Fantala 的結構最近改善很多
托南方槽線 帶來高層良好的極向輻散
今天颱風風眼快速清空 CDO 也變得較之前更為扎實
由稍早可見光雲圖雲圖 可清晰看到南方有相當明顯的針狀雲系
即是高層幅散良好的特徵
補充:
MFR 升格 強烈熱帶氣旋
WTIO30 FMEE 150629
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 17/8/20152016
1.A INTENSE TROPICAL CYCLONE 8 (FANTALA)
2.A POSITION 2016/04/15 AT 0600 UTC:
WITHIN 15 NM RADIUS OF POINT 12.3 S / 59.6 E
(TWELVE DECIMAL THREE DEGREES SOUTH AND FIFTY NINE DECIMAL SIX
DEGREES EAST)
MOVEMENT : WEST 10 KT
3.A DVORAK ANALYSIS: 5.5/5.5/D 1.0/12 H
4.A CENTRAL PRESSURE: 954 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 95 KT
RADIUS OF MAXIMUM WINDS (RMW) :28 KM
6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 130 SE: 220 SW: 200 NW: 130
34 KT NE: 110 SE: 170 SW: 150 NW: 90
48 KT NE: 80 SE: 110 SW: 100 NW: 70
64 KT NE: 60 SE: 70 SW: 70 NW: 60
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1007 HPA / 400 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION : DEEP
1.B FORECASTS:
12H: 2016/04/15 18 UTC: 12.2 S / 58.0 E, MAX WIND=100 KT, INTENSE TROPICAL CYCLONE
24H: 2016/04/16 06 UTC: 11.9 S / 56.6 E, MAX WIND=105 KT, INTENSE TROPICAL CYCLONE
36H: 2016/04/16 18 UTC: 11.5 S / 55.2 E, MAX WIND=110 KT, INTENSE TROPICAL CYCLONE
48H: 2016/04/17 06 UTC: 10.9 S / 54.0 E, MAX WIND=110 KT, INTENSE TROPICAL CYCLONE
60H: 2016/04/17 18 UTC: 10.4 S / 53.1 E, MAX WIND=105 KT, INTENSE TROPICAL CYCLONE
72H: 2016/04/18 06 UTC: 10.0 S / 52.7 E, MAX WIND=095 KT, TROPICAL CYCLONE
2.B LONGER-RANGE OUTLOOK :
96H: 2016/04/19 06 UTC: 11.1 S / 54.5 E, MAX WIND=065 KT, TROPICAL CYCLONE
120H: 2016/04/20 06 UTC: 13.4 S / 57.5 E, MAX WIND=060 KT, SEVERE TROPICAL STORM
2.C ADDITIONAL INFORMATION:
T=CI=5.5+
DURING THE LAST 6 HOURS, CLOUD PATTERN IMPROVED WITH THE RETURN OF AN
EYE ON SATELLITE IMAGERY, SURROUNDED BY COLD CLOUD TOPS. LAST
MICROWAVE DATA CONFIRMS THAT, SHOWING A DEEP CONVECTION RING ALL
AROUND THE WARM SPOT. THEREFORE, THE SYSTEM INTENSITY IS RAISED TO
INTENSE TROPICAL CYCLONE LEVEL. NORTH-NORTH-EASTERLY WIND SHEAR
ANALYSED BY THE CIMSS AT 00Z AROUND 12KT, DOES NOT SEEM TO IMPACT
FANTALA ANYMORE, WHICH STILL BENEFITS FROM AN EXCELLENT UPPER
POLARSIDE DIVERGENCE
THE SYSTEM KEEPS ON TRACKING WESTWARD ON THE NORTHERN SIDE OF A HIGH
GEOPOTENTIAL CELL LOCATED BETWEEN MADAGASCAR AND THE MASCAREIGNES
ISLANDS. FRIDAY, THE GRADUAL STRENGTHENING OF THIS HIGH SHOULD
ORIENTATE THE TRACK A BIT MORE NORTHWESTWARD. ON SATURDAY, FANTALA IS
FORECASTED TO TRANSIT A LITTLE LESS THAN 100 NM SOUTH OF AGALEGA AT THE
STAGE OF INTENSE TROPICAL CYCLONE.
FROM SUNDAY, THE SYSTEM SHOULD BE SLOWED BY A RIDGE IN ITS WEST AND
AXED OVER THE MOZAMBIQUE CHANNEL, AS THE HIGH CENTERED OVER THE
MASCAREIGNES WEAKENS. MONDAY, THE NEAR EQUATORIAL RIDGE IN THE
NORTH-EAST WILL TAKE OVER THE STEERING FLOW AND DRIVE A SHARP SOUTHEASTWARD
U-TURN OF THE SYSTEM. THE MOST RELIABLE NWP MODELS ARE IN
AGREEMENT AND STILL FORECAST A NARROW CLOCKWISE LOOP. HOWEVER, THE
EXACT LOCATION OF THE TURN REMAINS UNCERTAIN AS THE 12Z ECMWF
ENSEMBLE PREDICTION RUN FORECAST A MODERATE RISK THAT FANTALA CROSS
THE FARQHAR BEFORE DOING ITS TURN WEST OF THESE ISLANDS. HOWEVER
AMONG THE DETERMINISTICS NO RELIABLE MODEL GUIDANCE SUGGEST THE
CROSSING OF THE CENTER IN THE ARCHIPELAGO.
UP TO TUESDAY, FANTALA IS LIKELY TO UNDERGO RATHER CONDUCIVE UPPER
LEVEL ENVIRONMENT. THE NORTHERLY CONSTRAINT SHOULD REMAIN MARGINAL
WHILE POLAR SIDE DIVERGENCE IS EXPECTED TO INCREASE SUNDAY AFTER A
TEMPORARY DECAY SATURDAY. BUT, WEST OF 55E, THE LESSER OCEAN HEAT
CONTENT SHOULD BECOME THE LIMITING FACTOR FOR THE INTENSITY OF THE
SYSTEM. ITS INFLUENCE WILL BE ALL THE MORE IMPORTANT IF FANTALA SLOWS
DOWN AND RETURN ON ITS PREVIOUS TRACK WHERE WATERS ARE COLDER.
WEDNESDAY, A UPPER AND MID LEVELS TROUGH ARRIVES FROM THE SOUTH-WEST
AND MAY INDUCE A MODERATE NORTH-WESTERLY UPPER LEVEL CONSTRAINT.
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