Madagascar: OVERLAND DEPRESSION ex. IVAN (TC 18S)

[HURAKAN]

07/1430 UTC 14.0S 62.0E T3.0/3.0 IVAN -- South Indian Ocean

Continues to organize.

[Meso]

I saw the EURO showing a rather large storm approaching Mozambique in the next week or so,wonder if this is the one it was showing.

[HurricaneRobert]

I think Ivan is going the other way. It's unusual to have three storms in the Indian Ocean all headed east.

[HURAKAN]

Meteo France says Iván will recurve to the west. Very interesting. Meso, thanks for the image.

[HURAKAN]

NRL: 55kts-982mb

Based on the image above I think NRL is exaggerating a little bit.

[Squarethecircle]

55 knots?

I'd say maybe 35 max.

[Pedro Fernández]

NRL: 55kts-982mb

Based on the image above I think NRL is exaggerating a little bit.

I agree... Although MeteoFrance-Reunión gives 984 hPa and 50 KT........................ Too much to me as well.

[Meso]

For what it's worth,VERY interesting scenario the EURO shows

[Squarethecircle]

What the heck is it basing that off?

[HURAKAN]

----- Current Analysis -----
Date : 07 FEB 2008 Time : 193000 UTC
Lat : 14:36:28 S Lon : 62:27:59 E

CI# /Pressure/ Vmax
2.6 / 995.8mb/ 37.0kt

07/2030 UTC 14.8S 62.6E T3.0/3.0 IVAN -- South Indian Ocean

40 + 50 + IVAN = 110 / 2 = 55 knots!!!

I'm still trying to find how the JTWC found 55 knots!!!

[HURAKAN]

I bet someone is wrong!!!

[Coredesat]

For what it's worth,VERY interesting scenario the EURO shows

I think that intense system near Madagascar is a separate system; it's too high in latitude to be Ivan.

[Coredesat]

JTWC may be basing intensity on microwave imagery and not its actual appearance; I don't think Ivan's 55 kt either - 45 kt seems about right given the lack of convective organization. Microwave imagery would seem to indicate the presence of an eye:

[Chacor]

027
WTIO30 FMEE 080007

RSMC / TROPICAL CYCLONE CENTRE / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER : 4/11/20072008
1.A SEVERE TROPICAL STORM 11 (IVAN)

2.A POSITION 2008/02/08 AT 0000 UTC :
WITHIN 30 NM RADIUS OF POINT 15.3S / 62.8E
(FIFTEEN DECIMAL THREE DEGREES SOUTH AND SIXTY TWO DECIMAL EIGHT DEGREES
EAST)

3.A DVORAK ANALYSIS : 3.0/3.5 /D
4.A CENTRAL PRESSURE : 984 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 50 KT

6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 180 SE: 150 SO: 180 NO: 150

7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1006 HPA / 600 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS:
12H: 2008/02/08 12 UTC: 16.4S/63.5E, MAX WIND=050KT, SEVERE TROP. STORM.
24H: 2008/02/09 00 UTC: 17.0S/63.4E, MAX WIND=050KT, SEVERE TROP. STORM.
36H: 2008/02/09 12 UTC: 17.0S/63.2E, MAX WIND=055KT, SEVERE TROP. STORM.
48H: 2008/02/10 00 UTC: 16.7S/62.8E, MAX WIND=060KT, SEVERE TROP. STORM.
60H: 2008/02/10 12 UTC: 16.4S/62.6E, MAX WIND=060KT, SEVERE TROP. STORM.
72H: 2008/02/11 00 UTC: 16.2S/62.5E, MAX WIND=060KT, SEVERE TROP. STORM.

2.B OTHER INFORMATIONS:
T=3.0, CI=3.5
UPPER LEVEL CONDITIONS HAS IMPROVED WITH THE WEAKENESS OF THE NORTHERLY
CONSTRAINTE.

SYSTEM IS UNDER THE STEERING INFLUENCE OF THE THICK NORTHWESTWARDS FLOW
GENERATED BY THE MID-LEVEL EQUATORIAL RIDGE. THE SYSTEM SHOULD THEREFORE
KEEP ON TRACKING SOUTHEASTWARDS FOR THE NEXT 12 HOURS. THEN, AS THE
SUBTROPICAL RIDGE STRENGTHENS NEAR 70E AND A WEAKNESS IN THE SUBTROPICAL
HIGH PRESSURES
SHIFTS SOUTH OF THE SYSTEM, STEERING FLOW SHOULD BE WEAKER RESULTING IN
A GRADUAL DECREASE OF THE SPEED AND IN A SOUTHWARDS TRACK, THEN MORE WEST
SOUTHWESTWARDS VERY SLOWLY AS THE SUBTROPICAL RIDGE REBUILDS IN THE
SOUTH-WEST.

[Chacor]

Still 50 kt at 0600.

[HURAKAN]

Poorly-organized eye.

[parvez_savage]

Hmm Looking better now...Its starting to organize...

Tropical cyclone 18S / Ivan
Warning 03 at 0900 GMT
Position: 15.5S 63.3E
Location 725 miles SW of Diego Garcia
Movement: SE at 6 knots
Maximum sustained winds: 55 knots
Maximum gusts: 70 knots
Threatened landmasses: NONE
Next update from JTWC at 2100 GMT

Tropical cyclone Ivan has intensified and will attain hurricane strength within 24 hours. Atmospheric conditions are favourable for further strengthening. JTWC now partially joins the forecast from La Reunion, which shows a recurving of the cyclone's track to southsouthwest, later west (La Reunion).

HAZARD SUMMARY
Maximum significant wave height 18 feet
Tropical storm force winds occur within 75 miles of the centre.

[HURAKAN]

Beginning to look much better.

[Meso]

With what the EURO is showing,Mauritius could get a pounding.

[P.K.]

Thread title needs an update from the upgrade yesterday.

WTIO30 FMEE 081225

RSMC / TROPICAL CYCLONE CENTRE / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)

0.A WARNING NUMBER : 6/11/20072008
1.A SEVERE TROPICAL STORM 11 (IVAN)

2.A POSITION 2008/02/08 AT 1200 UTC :
WITHIN 20 NM RADIUS OF POINT 16.1S / 63.3E
(SIXTEEN DECIMAL ONE DEGREES SOUTH AND SIXTY THREE DECIMAL THREE DEGREES
EAST)

3.A DVORAK ANALYSIS : 4.0/4.0 /D 1.0/24 H
4.A CENTRAL PRESSURE : 980 HPA
5.A MAX AVERAGE WIND SPEED (10 MN) : 55 KT

6.A EXTENSION OF WINDS BY QUADRANTS (KM):
30 KT NE: 150 SE: 120 SO: 180 NO: 150
50 KT NE: 050 SE: 050 SO: 050 NO: 050

7.A FIRST CLOSED ISOBARE (PRESSURE / AVERAGE DIAM): 1008 HPA / 1000 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP

1.B FORECASTS:
12H: 2008/02/09 00 UTC: 16.4S/63.4E, MAX WIND=065KT, TROPICAL CYCLONE.
24H: 2008/02/09 12 UTC: 16.7S/63.4E, MAX WIND=070KT, TROPICAL CYCLONE.
36H: 2008/02/10 00 UTC: 16.9S/63.3E, MAX WIND=065KT, TROPICAL CYCLONE.
48H: 2008/02/10 12 UTC: 16.8S/63.0E, MAX WIND=060KT, SEVERE TROP. STORM.
60H: 2008/02/11 00 UTC: 16.6S/62.7E, MAX WIND=065KT, TROPICAL CYCLONE.
72H: 2008/02/11 12 UTC: 16.4S/62.3E, MAX WIND=070KT, TROPICAL CYCLONE.

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

OVERALL STRUCTURE IS STILL IMPROVING WITH THE BEGINNING OF A BANDING EYE
ON VIS IMAGERY. HOWEVER, ON IR, CONVECTION REMAINS IS NOT CONSOLIDED IN
THE SOUTHEASTERN QUADRANT.

AVAILABLE NWP MODELS REMAIN DISAGGREE FOR THE EVOLUTION OF IVAN. SOME (AS
NOGAPS, ARPTROP) STILL DRIVE THE SYSTEM EASTWARDS UNDER THE STEERING
INFLUENCE OF THE NEAR EQUATORIAL RIDGE. GIVEN THE PRESENT SOUTHWARDS
MOTION THAT PUT AWAY THE SYSTEM FROM THIS WESTNORTHWESTWARDS WINDS, IT IS
NOT THE SOLUTI
ON REFLECTED BY THE PRESENT FORECAST. AS SUGGESTED BY CEP, GFDN AND UKMO,
IVAN SHOULD BEEN IN A VERY WEAK STEERING FLOW WITHIN THE NEXT 24 HOURS
AND SHOULD TRACK MORE SLOWLY (ERRATIC MOTION IS POSSIBLE). MONDAY, TRACK
SHOULD TURN MORE NORTHWESTWARDS AS THE SUBTROPICAL RIDGE SHOULD BUILT
SOUTHWESTWAR
D.

IF ENVIRONMENTALS CONDITIONS REMAINS FAVORABLE FOR FURTHER DEVELOPMENT,
SOME FLUCTUATIONS ARE POSSIBLE IN INTENSITY IF THE SYSTEM STAY TOO MUCH
TIME OVER THE SAME WATER.

GIVEN THE WIDE SPREAD IN NWM SOLUTIONS, IT IS A LOWER THAN AVERAGE DEGREE
OF CONFIDENCE IN THIS FORECAST.