Intense Tropical Cyclone Giovanna

[Konstantinos]

A new tropical storm has been created in Indian Ocean.

http://tropic.ssec.w...00000000&loop=0

Edited February 10, 2012 by Konstantinos

[Somerset Squall]

12S has now been given the name Giovanna by MeteoFrance. Giovanna is moving west-southwestwards along the northern periphery of a subtropical steering ridge to the south. Giovanna poses a significant risk to Madagascar in the next several days as this motion is expected until landfall on the east coast of the country. Conditions are favourable for further intensification as shear is low, waters are warm and outflow is good. Giovanna already appears to be developing a central dense overcast feature, a sign of a maturing storm.

[Konstantinos]

From the prognosis of http://www.wunderground.com and http://tropic.ssec.wisc.edu the cyclone will pass in the capital of Madagascar. It is a city with population 900.000 and it is called Antananarivo.

http://en.wikipedia....wiki/Madagascar

http://en.wikipedia....ki/Antananarivo

Edited February 10, 2012 by Konstantinos

[Somerset Squall]

Giovanna has strengthened further to 50kts this morning. JTWC expect a peak at cat 3 intensity (SS Scale) prior to landfall. Looking like a very dangerous storm.

[Somerset Squall]

Giovanna continues to intensify quickly. Intensity has risen to 65kts, making the cyclone a cat 1 on the SS scale. A solid central dense overcast feature is in place with strong banding flanking it. An eye appears to be readily forming too. Further intensification, perhaps rapid, is expected. Giovanna will make landfall in about 80hrs time on the east coast of Madagascar. Giovanna could well survive the trip over Madagascar and emerge into the Mozambique Channel. Both MeteoFrance and JTWC favour this scenario.

[Somerset Squall]

Giovanna has rapidly intensified this evening, and is now a 110kt cat 3 (SS scale). Giovanna has developed a very small eye within the central dense overcast. The intense cyclone is expected to approach cat 5 status. Not good at all for Madagascar.

[Somerset Squall]

Now a cat 4 with intensity rising to 120kts.

[Konstantinos]

[Somerset Squall]

Giovanna has undergone an eyewall replacement cycle, and as a result has weakened to 105kts. Some re-strengthening is expected prior to landfall on Madagascar.

[knocker]

[Somerset Squall]

It seems Giovanna is a victim of it's own "success". It strengthened so rapidly it left the eye very unstable forcing the eyewall replacement cycle, which it appears Giovanna is struggling to recover from.

[Somerset Squall]

Giovanna is now sporting a large but well defined, cloud free eye. Looks scary for Madagascar. Giovanna is easily a cat 4 again for sure.

[Konstantinos]

[Somerset Squall]

Giovanna has reached a new peak of 125kts. It appears Giovanna is just beginning another eyewall replacement cycle however, so the intense cyclone could weaken a little prior to landfall which will occur later tonight/early tomorrow. However, this does not mean that Giovanna will be any less dangerous. Giovanna is expected to weaken but survive it's trip over Madagascar before emerging into the Mozambique Channel. Here, some slight restrengthening is expected over warm water before the westwards track drives Giovanna onto the coast of Mozambique where a second landfall will occur.

[BornFromTheVoid]

http://www.esa.int/images/giovanna-cycloneMER_FR_20120213_small.jpg

[Somerset Squall]

Giovanna has crossed Madagascar quickly causing a lot of damage and flooding. Reports will confirm the amount of dead and the severity of the damage in the coming days. This cyclone isn't done yet. Although Giovanna has weakened to 35kts (expected as it has interacted with very rugged terrain), the storm has moved quickly and is already emerging into the Mozambique Channel. The track forecast has changed, and is leaning away from a landfall in Mozambique and is now favouring a slow curve to the southwest then a swing to the southeast in the middle of the channel. The change to the track is because the ridging to the east and southeast of Madagascar is expected to continue to have the most influence over Giovanna, and the cyclone will move around the western periphery of the ridge in a southward direction. Ridging over South Africa is no longer expected to control steering and force Giovanna westwards onto the Mozambique coast. Giovanna should re-intensify over the warm waters of the channel over the next day or two, as shear remains light too.

[Somerset Squall]

Giovanna has reintensified to 55kts. The cyclone is moving southwards and is expected to sharply turn eastwards as it rounds the periphery of the steering ridge anchored east of Madagascar. This track will take Giovanna inland across southern Madagascar. This is a big departure from the original forecasts indicating a westward track into Mozambique. MeteoFrance and JTWC are finally in agreement on track. Hats off to Meteofrance for insisting on the southeastwards recurve whilst the JTWC continued to disagree, forecasting Giovanna to head west.

Edited February 16, 2012 by Somerset Squall

[knocker]

Rain-soaked Madagascar again threatened by Cyclone Giovanna

Rainfall data from NASA's TRMM satellite revealed that parts of Madagascar's east coast received over a foot (30 cm) of rainfall from Cyclone Giovanna's passage, and new satellite data shows Cyclone Giovanna re-strengthening and turning back toward southeastern Madagascar.

The Tropical Rainfall Measuring Mission (TRMM) satellite, managed by both NASA and the Japanese Space Agency obtains rainfall rate data from space and acts like a flying rain gauge. That data is analyzed to determine how much rain falls from certain events. In a Multi-satellite Precipitation Analysis (TMPA) done at the NASA Goddard Space Flight Center in Greenbelt, Md. on Cyclone Giovanna's rainfall from February 8-15, 2012, the highest rainfall totals of over 250mm (~10 inches) fell in the coastal area east of Madagascar's capitol of Antananarivo. In that area people were flooded out of their homes and deaths have been reported.

http://www.eurekalert.org/pub_releases/2012-02/nsfc-rma021712.php

[Somerset Squall]

Indeed Weathership, Giovanna really doesn't want to leave Madagascar alone!

Giovanna reached a 65kt intensity again earlier and a well defined eye appeared for a few hours. This eye feature is now cloud obscured, and the intensity has fallen slightly to 60kts. Giovanna is tracking eastwards south of the south coast of Madagascar, which is a departure again from the forecast tracking the cyclone over land. The cyclone will continue to move eastwards potentially delivering some heavy rains to te south of the country. Giovanna is then expected to swing northwards in response to TC13S approaching from the east. TC13S is expected to be the dominant system and shear Giovanna. But not before Giovanna drenches the east coast of Madagascar with further flooding rains.

I can't quite remember a cyclone almost completely circling Madagascar like this. What a bizarre track!

[Somerset Squall]

Giovanna is back up to 65kts this morning. The cyclone maintains some intense inner core convection and a cloud obscured eye. Giovanna should turn to the north is response to TC13S approaching from the east, however, if 13S remains weak Giovanna may turn towards the southeast as 13S will not have enough steering influence over it.

[Somerset Squall]

Giovanna has rapidly intensified again this afternoon, with intensity rising to 85kts, making the cyclone a cat 2 on the SS scale. Giovanna's eye cleared out again but it has once again become cloud filled in the last few hours. Giovanna is no longer expected to turn north as TC13S remains weak. Instead, Giovanna will be caught in the westerlies and will track southeastwards whilst transitioning into an extratropical cyclone.

[Somerset Squall]

The forecast changed again as shear rapidly rose over Giovanna, stripping the convection away from the cyclone, leaving the LLC to drift towards the north and dissipate. An interesting watch to say the least, and a very unusual track.

[Konstantinos]