Direction Interrégionale de LA REUNION
B.P.4    97491 Ste Clotilde Cedex
Téléphone                02.62.92.11.00
Fax exploitation      02.62.92.11.48
Fax direction           02.62.92.11.47


WTIO30 FMEE 070048 CCA

*************** CORRECTIVE **************
RSMC / TROPICAL CYCLONE CENTRE / LA REUNION
TROPICAL CYCLONE TECHNICAL BULLETIN (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER : 11/8/20092010
1.A SEVERE TROPICAL STORM 8 (EDZANI)

2.A POSITION 2010/01/07 AT 0000 UTC :
WITHIN 20 NM RADIUS OF POINT 13.8S / 80.4E
(THIRTEEN DECIMAL EIGHT DEGREES SOUTH AND EIGHTY DECIMAL FOUR DEGREES
EAST)
MOVEMENT : WEST-SOUTH-WEST 9 KT

3.A DVORAK ANALYSIS : 4.0/4.0 /D 1.5/24 H
4.A CENTRAL PRESSURE : 980 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 55 KT
RADIUS OF MAXIMUM WINDS (RMW) : 30 KM

6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 250 SE: 150 SO: 100 NO: 250
50 KT NE: 040 SE: 040 SO: 040 NO: 040

7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1008 HPA / 1450 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS:
12H: 2010/01/07 12 UTC: 14.5S/79.1E, MAX WIND=065KT, TROPICAL CYCLONE.
24H: 2010/01/08 00 UTC: 15.0S/77.9E, MAX WIND=075KT, TROPICAL CYCLONE.
36H: 2010/01/08 12 UTC: 15.5S/76.5E, MAX WIND=080KT, TROPICAL CYCLONE.
48H: 2010/01/09 00 UTC: 16.1S/75.0E, MAX WIND=085KT, TROPICAL CYCLONE.
60H: 2010/01/09 12 UTC: 16.9S/73.2E, MAX WIND=090KT, INTENSE TROP. CYCL..
72H: 2010/01/10 00 UTC: 17.8S/70.8E, MAX WIND=095KT, INTENSE TROP. CYCL..

2.B OTHER INFORMATIONS:
T=CI=4.0-

FT BASED ON MET (RAPID INTENSIFICATION OVER TH ELAST 24 HOURS). PT AGREES
.

MW IMAGERY (AMSRE 2010Z AND NOAA 19 2046Z) SHOW A BUILDING EYE AT THE MID
-LEVEL (CHANNEL 89/91 GHZ). IN THE LOW LEVEL, LLCC HAS IMPROVED SINCE
TRMM PASS OF 1502Z WITH CONTRACTION OF RMW.

SINCE 20Z, SATELLITE PRESENTATION HAS IMPROVED.

IT IS LIKELY THAT INTENSITY OF THE PREVIOUS ADVOSORY HAS BEEEN
UNDERESTIMATED AS SYSTEM HAS PRESENTED A CURVED BAND PATTERN AT 0.8 (T 3
.5) FEW TIMES AFTER THE FIX.

SYSTEM KEEPS ON TRACKING WESTSOUTHWESTWARD, THE STEERING FLOW IS A
SUBTROPICAL RIDGE IN ITS SOUTH-EAST EXISTING IN THE LOW AND
MID-TROPOSPHERE.

UPPER LEVEL DIVERGENCE IS GOOD SPECIALLY EQUATORWARD.
A POLEWARDS OUTFLOW SHOULD BUID TODAY AS A SHORT WAVE UPPER LEVEL TROUGH
IS CURRENTLY PASSING TO THE SOUTH. SYSTEM IS ALSO OVER HIGH HEAT CONTENT
WATERS ...

AVAILABLE NUMERICAL GUIDANCES HAD PROGRESSIVELY SHIFTED SOUTHWARDS OVER
THE LAST 24 HOURS REGARDS TO THE CORRESPONDING SHIFT OF ECMWF'S TRACKS ..
. OVER THE FORECAST PERIOD (UP TO 72 HOURS), THE SPREAD IS RATHER LOW BUT
IT IS GETTING STRONGER BEYOND THAT RANGE. AT TAU 72HRS, A WEAKNESS
SHOULD APPEAR
IN THE STR DUE TO A MID-LAT TROUGH. UKMO AND ECMWF DISAGREE ON HOW STRONG
THE IMPACT OF THE MID-LAT TROUGH ON THE STR WILL BE ... ECMWF TAKES A
MORE POLEWARDS TRACK AT TAU 96 AND TAU 120 UNDER THE INFLUENCE OF THE
TROUGH. UKMO TAKES A MORE ZONAL TRACK WITH A STRONGER STR BUT TAKES INTO
ACCOUNT A WEA
KER SYSTEM (LESS LIKELY).