Micro-burst winds

Micro-burst wind as supercell storm passed over Malta during the very early part of the afternoon. Although the video in itself is not spectacular, the meteorology behind this storm was. The precipitation-estimate satellite image showed that the supercell actually split with the left-mover weakening rapidly and the right one holding on to its strength before eventually dissipating too. This wet micro-burst was precipitation-driven (as can be clearly seen from the video) meaning that the strong winds were the direct result of the heavy-rainfall which was falling. The storm statistics were as follows: Highest gust during the storm was 86kmh (Force 9) while precipitation values ranged between 14 and 24mm (most of this falling within 15 minutes). Precipitation rate was estimated at 25mm per hour by the EUMetSat althaugh locally much heavier bursts are not excluded. During the storm, air temperature fell from 25C to 18C. The storm began its life cycle as a small cloud which quickly grew into a supercell over the Eastern coast of Tunisia very early that morning and probably fuelled by the very warm sea surface temperature present there. At one point its movement became erratic (or even stalled) while intensifying all the time. This storm then suddenly split in 2 with the left mover weakening rapidly and moving towards SE Sardinia while the right mover maintained its strength for some time and lashed Malta from the SW. The attached weather sounding showed a region in the lower levels were the air temperature was not changing with altitude (known as `cap`). Such cap might have allowed the formation of an updraft of sufficient strength to form this supercell when the cap was eventually eroded by diurnal heating. Note: Such storms, though not unheard of, are rather unusual over the Maltese Islands. Combined with previous severe storms this might be indicating a trend towards a change in storm behaviour due to the warming up of the Mediterranean Sea itself.

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