Med Cyclone ‘Invest 90M’

Huge sea waves on the NE coast of Malta as the low pressure system (along with the patch of colder air that initiated it) being cut off from the main jet stream began to acquire tropical characteristics over the warm Mediterranean Sea becoming more compact and actually developing an eye similar to a hurricane. Its only inhibiting factor was the lack of a strong jet streak to remove the accumulated rising air high in the troposphere. At this stage, when the Maltese Islands were most affected on this day, the whole system was actually a pure sub-tropical storm mostly because of its broad wind field hence having both characteristics of tropical storms and mid-latitude cyclones. Unlike normal mid-latitude cyclones, this weather feature had also developed a warm-cored centre indicated by higher freezing level on the 6th thumbnail. Contrary to expectations, fused thunderstorm clouds with heavy rain remained well offshore and had only surrounded the immediate eye wall. Over the Maltese Islands, the effects of this sub-tropical storm was very similar to strong Gregale conditions that effect our Islands from time to time in Winter with the exceptions that it came unusually early in the year and that it managed to cause localized flooding from sea water especially in Sliema and Marsascala probably due to a large fetch from a broad wind field as maximum wind gusts “only“ reached the 83kmh (Force 9) early that morning on land and the NE wind had generally varied between Force 7 and Force 8, hardly severe wind gusts. The weather sounding which is clickable on the 3rd thumbnail showed exactly the right ingredients for a Mediterranean cyclone to develop being a very moist profile and almost homogeneous wind at all levels of the atmosphere, this time dominated by NE winds, also causing the storm to move in a southwesterly direction before stalling and eventually moving eastwards on the following day on Sunday. The first two thumbnails show the sea invading all the coast in Xghajra with a natural white foam (definitely not fish slime) and flooding with sea water in Marsascala respectively, both coasts being on the eastern side of Malta where the Gregale effects are felt with the worst effected being Sliema and Valletta. The fourth and fifth thumbnail show the visible (daytime) satellite image of the sub-tropical storm and its wind field respectively clearly showing its asymmetry (non-symmetrical) and that the strongest wind was found towards the northwest quadrant specifically over the Maltese Islands. More photos available upon request.

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