The tropical-like cyclone hits Italy, Sicily and Malta

Medicane Qendresa hits Malta and Sicily

7 November 2014 03:00 UTC–8 November 12:00 UTC

The tropical-like cyclone hits Italy, Sicily and Malta
The tropical-like cyclone hits Italy, Sicily and Malta

A Medicane (MEDIterranean hurriCANE) or Tropical-Like Cyclone (TLC) brought severe weather to parts of the Mediterranean in early November.

Last Updated

06 September 2022

Published on

07 November 2014

By Jochen Kerkmann and Mark Higgins (EUMETSAT), Sancha Lancaster (Pactum), Hans-Peter Roesli (Switzerland), Eleftheria Tsiniari (Hellenic National Meteorological Service) and Dr Michael Sachweh

On 7 November the storm first hit Lampedusa on the island of Linosa, then Malta (at around 16.30 UTC) and then the eastern coast of Sicily before it disappeared to the east.

 S-NPP, VIIRS Day-Night Band and I5, 08 November 01:43 UTC
Figure 1: SNPP VIIRS Day-Night Band and I5, 8 November 01:43 UTC

Gusts of 135km/h were recorded at Lampedusa in Linosa and up to 154km/h in Malta. Airport and ferry operations were suspended and many areas were left without power, as the storm caused damage across the three countries.

The system can be clearly seen on the a Day-Night-Band image (750m resolution) in black and white with yellow hues of IR11.45 (band I5 at 375m resolution) from cold-white to warm-yellow — high cloud appears white, lower cloud and artificial light is yellow (Figure 1). The scene is well lit by the full Moon.

The Airmass RGB animation (Figure 2), shows the birth of the medicane out of cut-off low and its progress across the Mediterranean. It also shows the deceleration of the rotation after the TLC hit the Catania coast.

Figure 2: Meteosat-10 Airmass RGB, 7 November 03:00 UTC–8 November 12:00 UTC

Earlier in the week the heavy rains from the deep trough, at the origin of the cut-off, had caused Lago Maggiore in the Alps to overflow.

A branch of a polar jet stream over south western Europe headed sharply towards the south, starting to meander over Tunisia. In the Water Vapour (WV 6.2µm) images from 6 November 18:00 UTC–8 November 00:00 UTC (Figures 3–8) the location of the jet stream is identified as a strong gradient from high to low humidity (dark stripes).

Met-10 Water Vapour, 6 Nov 18:00 UTC
Figure 3: Meteosat-10 Water Vapour, 6 November 18:00 UTC
Met-10 Water Vapour, 7 Nov 00:00 UTC
Figure 4: Meteosat-10 Water Vapour, 7 November 00:00 UTC
Met-10 Water Vapour, 7 Nov 06:00 UTC
Figure 5: Meteosat-10 Water Vapour, 7 November 06:00 UTC
Met-10 Water Vapour, 7 Nov 12:00 UTC
Figure 6: Meteosat-10 Water Vapour, 7 November 12:00 UTC
Met-10 Water Vapour, 7 Nov 18:00 UTC
Figure 7: Meteosat-10 Water Vapour, 7 November 18:00 UTC
Met-10 Water Vapour, 8 Nov 00:00 UTC
Figure 8: Meteosat-10 Water Vapour, 8 November 00:00 UTC

Water vapour imagery clearly shows the stratospheric air extruded well downwards into the troposphere indicative of strong cyclogenesis. The sequence of WV images also reveal the main stages of this development. Noteworthy features can be seen, such as baroclinic leaf, a comma head and the cloud hook (Figures 3 and 4).

 Met-10 Airmass RGB, 7 Nov 12:00 UTC
Figure 9: Meteosat-10 Airmass RGB, 7 November 12:00 UTC

After 12:00 UTC, the characteristic dry swirl pattern is evident (Figures 6–8), indicating that the cyclone was entering the occluded phase of its life cycle.

A scalloped pattern is clearly visible along the dark WV stripe, indicating a maximum of cyclonic shear vorticity (Figures 4 and 5 – yellow arrow).

The position of the jetstream can also be seen in the Airmass RGB image, 7 November 12:00 UTC (Figure 9) where there is a colour difference (red changes to purple – black arrows).

Figure 10 shows the storm seen from Metop-B on 7 November at 08:25 UTC. The images are the 0.6 micron channel from AVHRR and the winds are taken from ASCAT 12.5km coastal wind product. The winds are approximately hour mean winds, showing the gross speed and direction — gusts will have been much stronger. Areas with wind greater than 74km/h (40kts) are shown in brown and red.

Image comparison

Metop-B AVHRR with 12.5 km ASCAT winds overlay, 07 November 2014, 08:25 UTC compare1
compare2
 

Figure 10: Comparison of Metop-B AVHRR images of the medicane, with and without ASCAT winds.

The animated gif of Meteosat-10 HRV imagery, from 07:00–11.45 UTC (Figure 11), shows the storm over Lampedusa.

 Met-10 HRV imagery, 7 Nov 07:00–11:45 UTC
Figure 11: Meteosat-10 HRV imagery, 7 Nov 07:00–11:45 UTC

Development of marine conditions using ASCAT observations

The region to the south of the low pressure centre is a region of strong pressure gradient, with resulting strong winds. The wind field near the surface can be captured by the Advanced Scatterometer (ASCAT) instruments on board the Metop satellites (Figure 12).

 Metop-B ASCAT winds, 07 Nov, 08:37 UTC
Figure 12: Metop-B ASCAT winds, 7 November 08:37 UTC
 Metop-A ASCAT winds, 07 Nov, 09:25 UTC
Figure 13: Metop-A ASCAT winds, 7 November 09:25 UTC

A close examination of the wind direction retrieved from ASCAT Metop-B (Figure 12) showed a defined vortex with maximum speed of more 50kt (92km/h).

 Metop-B ASCAT winds, 07 Nov, 19:56 UTC
Figure 14: Metop-B ASCAT winds, 7 November 19:56 UTC

According to Figure 12 the centre of the system was located east of the coasts of Tunisia at about 08:37 UTC. The winds exceeded 50kt locally to the south and southwest of the low where the wind flow converged.

We have similar vector winds observations from ASCAT on Metop-A at 09:25 UTC (Figure 13).

At about 18:00 (19:56 UTC), as the low pressure system had moved eastwards, west northwest winds of 40–45kt maxima value were observed in the area of interest (Figure 14).

The tropical-like cyclone of 7 November 2014 seems to have been a notably severe one, with gradient wind strengths up to 75kt over the island of Lampendusa (ICAO index LICD). This value of wind speed coincides with the data retrieved from ASCAT at the same time.

Strong winds produced high waves of about 3m or more. The highest waves were located right of the track of the cyclone, at the 'danger semicircle' as was expected.

Observations of both wave and swell height show that a wave height of 6ft (about 3m of total wave height) in the area between Sicily and Malta at 02:00 UTC, seem in good agreement with the model forecast.

According to the Extreme Forecast Index (EFI) values, the marine situation seems to have been unusual and dangerous, and could have been expected to generate strong swells.

Taking into account the fact that the model wave height fields showed a wave maximum area exceeding the threshold values warnings, it would be expected that warnings would be issued. Indeed, Greece, who is responsible for the provision of marine bulletins for the eastern Mediterranean Sea and Black Sea, issued a strong gale warning for Boot, Sidra Melita and Gabes.

The intensity of the wind field was quite well forecast: the cyclone lost its strength after landfall (Figure 15) at about 02:00 UTC on 8 November, and began to weaken rapidly, as seen from the Metop-B ASCAT winds on 8 November at 08:16 UTC (Figure 16).

 SNPP Day-Night Band (DNB), 08 Nov, 01:43 UTC
Figure 15: SNPP Day-Night Band (DNB), 8 November 01:43 UTC
 Metop-A ASCAT winds, 08 Nov, 08:16 UTC
Figure 16: Metop-A ASCAT winds, 8 November 08:16 UTC

The models did well in forecasting the location of the storm centre, the drop and timing of mean sea level pressure and the significant wave height.

The strong winds near the centre of the storm, were not well described in the models because of the rapid deepening of the cyclone.

Satellites as weather observing tools seem to offer a new dimension in the field of marine meteorology improving markedly forecasting ability.

Addendum by Dr Michael Sachweh

MSG — Rapid Scans

Meteosat-9 RGB, 7 November 12:00 UTC (source: RGB images created by MeteoGroup)
Figure 17: Meteosat-9 RGB, 7 November 12:00 UTC (source: RGB images created by MeteoGroup)
Download animation, 7 November 06:45 UTC–8 November 08:13 UTC
Watch the animation on YouTube

The RGB animation shows the development of Medicane Qendresa as seen by Meteosat-9 5-minute rapid scans, from the birth in the area of Pantelleria to its dissipation in the area east of Sicily.

The standard RGB using the HRV and the IR10.8 channels is shown (i.e. RGB HRV-HRV-IR10.8).

In the night the images look bluish as the HRV images (which are put on the red and green beams) are not available at night. From 17:15 UTC to 05:00 UTC the images are only available at 15-min frequency, thus the imagery judders slightly during the night hours.

Dissipation of the storm

The land contact of Qendresa over eastern Sicily (overnight 7–8 November) caused a reduction of the energy, moisture and fluxes from the warm sea surface, and also led to an unbalance of the system both of which probably contributed to the quick dissipation on 8 November. Storms of this kind are very sensitive to rotational asymmetries.

Strong winds in Catania

It is interesting to note that, during the passage of Qendresa, Catania recorded very strong N to NE winds. This could be a barrier effect, from Mount Etna, which enhanced the winds on the left side of the vortex (a funnelling effect).

This northerly funnel might be the reason why the system, after hitting Sicily, moved back to the south. It would be interesting to simulate this case with high-resolution NWP models.

Radar/precipitation

As previously stated, Qendresa caused heavy precipitation in Malta and Sicily.

On 8 November, more than 100 mm in 24 hours were recorded in the Catania and Ragusa Provinces.

The animated GIF of the radar (Figure 18) nicely shows the eye as the storm passed along the east coast of Sicily, revealing the tropical storm nature of Qendresa.

Rainfall radar, 8 November 02:00–06:00 UTC
Figure 18: Rainfall radar, 8 November 02:00–06:00 UTC. Source: Protezione Civile, Italy
Ground observations

Because of its track hitting several synop stations, Qendresa offered perfect ground truth observations of a Medicane (e.g. the pressure funnel recorded on the Island of Linosa , Italy).

 
Pressure funnel recording at Bugibba, Malta
Figure 19: Pressure funnel recording at Bugibba, Malta

The recording at Bugibba, in the north-west of Malta, perfectly shows the structure of a tropical storm:

  1. The eye-wall with average winds of 111km/h and gusts up to 154km/h.
  2. 15 minutes later, the eye of the storm (see pressure funnel) with totally calm conditions (no wind) with a remarkable pressure of 978.6hPa.
  3. The second eye wall with about 50km/h winds.

Topografic effects may have increased the wind (first eye wall) or reduced the wind (second eye wall), as the wind recording is not symmetric, unlike the pressure recording.

This photograph shows the damage north of Catania (Giardini-Naxos) from Cosimo Manitta.

 

Additional content

Further analysis from Dr Michael Sachweh (in German)
Rare Medicane Hits Malta and Sicily With Tropical Storm-Like Conditions (Weather Underground)
Rare Medicane Hits Malta and Sicily With hurricane Conditions (Live Leak)
A tropical cyclone and torrential rain hit Sicily (Reuters video)
Maltempo, ciclone tropicale a Malta - 7 novembre 2014 (MeteoWeb/YouTube)
Update 3: Airport operations resume, several areas without power, cars damaged as fierce storm lashes Malta (Times of Malta)