Tropical Depression 03B

Tropical depression 03B

20–25 October 2008

Tropical Depression 03B
Tropical Depression 03B

Tropical depression 03B cut a destructive path over the Arabic Peninsula in October 2008.

Last Updated

25 May 2022

Published on

20 October 2008

By Cecilie Wettre, Jochen Kerkmann and Alexander Jacob (EUMETSAT)

The third tropical cyclone of the season in the northern Indian Ocean brought rare rains to the desert regions of Somalia, Yemen, Oman and Saudi Arabia in the third week of October 2008 after the storm steered around the Horn of Africa and entered the Gulf of Aden (see 7-day Meteosat-9 IR10.8 animation, 19–25 October).

Tropical Storm Three formed in the Indian Ocean southeast of the island of Socotra and headed northwest over the island. The Meteosat-7 visible image below shows the tropical storm on 21 October when it skirted the Horn of Africa and headed west. During this phase, the east coast of Somalia received significant amounts of rainfall, as confirmed by the TRMM-based, Multi-satellite Precipitation Analysis (MPA) of the NASA Goddard Space Flight Center (see MPA rainfall totals for the period 18 to 26 October 2008, source: Hal Pierce (NASA)). Although 03B never exceeded a minimal tropical storm, it dumped up to 150 mm of rain over eastern Somalia.

As mentioned above, the storm only briefly reached tropical storm status before it weakened to a tropical depression. One reason for not reaching tropical cyclone status was probably the strong wind shear at higher levels which gave the storm the typical shear pattern (see animation below the image and typical tropical cyclone patterns (P Caroff, 2004)).

Tropical Depression 03B
Figure 1: Meteosat-7 Visible, 21 October 2008, 09:00 UTC. Large Area Animation (05:00–11:00 UTC)

As of Wednesday 22 October, the tropical depression steered northwest over the eastern Gulf of Aden bound for southern Arabia (see Metop-A ASCAT wind product below). The leading edge of its tropical moisture was already spreading ashore over Oman and Yemen, where it was spawning scattered downpours. At Salalah, in southwestern Oman, rainfall was 2.5cm as of Wednesday 22 October.

The Metop-A ASCAT wind product shows the tropical depression as it approached Yemen.

Tropical Depression 03B
Figure 2: Metop-A ASCAT wind product, 22 October 2008, 18:18 UTC
Large Area (source: KNMI)

Tropical depression 03B cut a destructive path over Yemen on Thursday and Friday, 23–24 October. The depression landed near Al Mukalla in the region of Hadramawt, then swept inland, ultimately dissipating over southwestern Saudi Arabia. The highest rainfall from 03B is thought to have reached 10 to 20cm (see Meteosat-9 Multisensor Precipitation Estimate (MPE) product below). Normal yearly rainfall hereabouts is around 2.5 to 5cm. This moisture triggered downpours that resulted in local flooding in areas that can see a year or more pass without significant rainfall.

Damage from the storm has been extensive in Hadramut — Yemen's largest province (see map of Yemen showing the areas most affected, Source: IRIN, OCHA). This corner of Arabia is normally extremely dry, and homes here have been built with mud bricks for thousands of years. These bricks melted away under the assault of sustained downpours. At least 1,700 houses in the southern provinces of Mouhra and Hadramut alone have been destroyed, according to Yemen's official news agency.

One heavily afflicted site is the town of Shibam, a UNESCO world heritage site with towering 16th century mud brick buildings that earned it the name 'the Manhattan of the desert'. Many of these high-rise mud buildings have collapsed (source: Aljazeera).

Hundreds of families are homeless or trapped by the flood waters, and scores of people are still missing, said Hamid el-Kharashi, a police chief in the remote southern province of Hadramut. The government has struggled to distribute relief supplies because the floods have washed out many roads (source: Welt Online).

Figure 3 is the Meteosat-9 MPE product used to estimate accumulated daily precipitation.

Tropical Depression 03B
Figure 3: Meteosat-9 MPE product on IR10.8 background image, 24 October, 00:00 UTC. Large Area. Colour Scale

On Saturday and Sunday, 25–26 October, Tropical depression 03B sent tropical moisture well inland over southern Arabia following its landfall over eastern Yemen. As shown on the Meteosat-9 IR10.8 image below, this moisture triggered downpours that resulted in local flooding in areas that can see a year or more pass without meaningful rain. Figure 4 is ex-Tropical Storm 3B as it caused convective precipitation over Saudi Arabia.

Tropical Depression 03B
Figure 4: Meteosat-9 Channel 09 (IR10.8, colour enhanced), 25 October 2008, 21:00 UTC. Large Area
Animation (19–25 October)

An interesting feature which could be seen well on the Meteosat imagery the days after the storm (see example below), is areas of wet and cool surfaces in Oman, Yemen and Saudi Arabia, exactly where ex-Tropical Storm 03B passed over the previous days. They appear as stationary white patches in the infrared images. Due to evaporative cooling, the areas that received precipitation are about 10K cooler than the surrounding areas. It should be noted that this surface moisture effect is more evident in arid areas where the surface is very dry than in densely vegetated areas (see case study Tracks of cool, wet surfaces from convective precipitation in South Africa).

The precipitation tracks can be seen in Meteosat IR images.

Tropical Depression 03B
Figure 5: Meteosat-9 Channel 09 (IR10.8), 27 October 2008, 09:00 UTC. Large Area

Additional content

Quikscat wind product (18 October 01:40 UTC, source: KNMI)
Quikscat wind product (19 October 01:34 UTC, source: KNMI)
Quikscat wind product (19 October 14:12 UTC, source: KNMI)
Meteosat-9 HRV image (20 October 03:30 UTC)
TRMM PR & TMI precipitation product (20 October 03:49 UTC, source: NASA)
Meteosat-9 IR10.8 image (20 October 06:00 UTC)
Metop-A ASCAT wind product (20 October 17:18 UTC, source: KNMI)
TRMM PR and TMI precipitation product (23 October 02:39 UTC, source: NASA)
Meteosat-7 VIS image close to landfall (23 October 05:30 UTC, source: JTWC)
Meteosat-9 MPE product (23 October 08:30 UTC)
Terra MODIS True-colour RGB image (23 October, source: NASA)