Medicane Ianos op de Middellandse Zee op weg naar Griekenland

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Medicane Cassilda aims for Greece?
Severe Medistorm Cassilda formed near Libya, Mediterranean Sea on September 15, 2020. This is the first severe medistorm of the 2020/21 Mediterranean medicane season which began on July 1. The storm was named by the Mediterranean Cyclone Center, an unofficial organization studying medicanes and eurocanes.

At 05:30 UTC today, the storm had maximum sustained winds of 65 km/h (40 mph) and pressure of 1 010 hPa. It was moving NNW at 10 km/h (6 mph).

Further strengthening is expected over the next 48 hours and the storm is forecast to strike Greece on Thursday evening, September 17, or Friday morning.

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A few NWP models (e.g. IFS and ICONEU) suggest the development of a low-level cyclone under the blob of deep convection in the Libyan Sea during Tue 15/09 and early morning on Wed 16/09. By the time of issuing this outlook (Mon 14/09, 20z), no visible near-surface vortex exists in the Gulf of Sidra. In addition, there is no strong mid/upper-level vorticity in the analysis maps to support the development of a strong surface cyclone and eventually support these NWP model scenarios that deep convection will be able to diabatically intensify this cyclone by generating large values of low-level PV. Even though a tropical transition of a cyclone is very unlikely to happen by the end of this outlook, this interesting set-up needs to be monitored closely for the following 48 hours.

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A level 2 was issued across south-western Greece for extreme rainfall.

Ionian Sea towards Greece

Models still indicate intensification of the subtropical cyclone during the period, with winds reaching Hurricane intensity. The vortex reveals very moist profiles, with a deep layer of rich moisture, skinny and marginal CAPE profiles and moderate to strong shear especially in the lowest 3 km in response to the warm-core low. Despite marginal CAPE, embedded deep moist convection is capable of producing excessive rain due to an effective warm rain process with a large warm cloud layer, rich moisture and favorable low-level inflow for training storms. These are forecast to contribute to the flash flood risk, especially where upslope flow is present. Elongated and curved hodographs in the northern quadrant indicate an augmented tornado risk in the northern part of the level 2 area.

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A level 3 is issued for a confined area in W Greece for severe convective wind gusts.

The subtropical storm 2020M01 over the Ionian Sea has possibly reached hurricane strength by Thursday evening while it maintains a slow eastward track towards the central west coast of Greece. The Thursday 12 UTC model runs havy largely converged to a track passing between the islands of Zakynthos and Kefalonia shortly before Friday 06 UTC (the beginning of this forecast period). WRF is the only remaining forecast model that still shows a southerly track over the open sea staying slightly southwest of Zakynthos.
Widespread hurricane-force wind gusts (>32 m/s) and extremely intense rainfall are very likely within a few tens of kilometers around the cyclone's center, and this risk extends for at least some hours into the current forecast period. It is not certain whether the innermost rain bands will also be accompanied by thunderstorms - there were only occasional flare-ups of electric activity on Thursday -, but with a few hundred J/kg CAPE in place the chances are high enough to meet our level 3 criteria in a confined area around the expected track of the cyclone's center. In inland areas, the wind risk diminishes betimes, but extraordinary rainfall accumulations, probably exceeding 200 mm in some regions with either prolonged upslope flow or beneath almost stationary and backbuilding rain bands, can easily cause catastrophic and life-threatening flash floods, mudslides and debris flows. Apart from the immediate vicinity of the cyclone center, another hot spot for abundant precipitation with embedded convection is expected to emerge on the northeastern side of the Greek mainland, where very moist and slightly unstable air from the Aegean Sea is persistenly advected against the mountains at the northern periphery of the circulation.
The further fate of the subtropical storm after Fri 12 UTC - either a quick filling over the Gulf of Patras, "disturbed" by the surrounding land mass, or a loop back southward into open sea waters with a slower filling or even partial recovery - will govern how quickly or slowly the wind risk decreases from Friday afternoon onwards, and how large the affected regions will be. The flooding risk is expected to continue into Saturday. For more details and updated information on this subtropical storm, please refer to our experimental 12-hourly Subtropical Cyclone Track and Intensity Forecasts and to the official warnings from the Hellenic National Meteorological Service (HNMS).

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Zeer zware storm Ianos aan land gekomen in Griekenland
18 september 2020 05:28

Een medicane is vrijdagochtend (lokale tijd) aan land gekomen in Griekenland. De zeer zware storm, Ianos genaamd, brengt windstoten tot 110 kilometer per uur, hevige regenval en hoge golven in de kustregio met zich mee.

De storm heeft tropische kenmerken en is boven de Middellandse Zee ontstaan. Soortgelijke stormen worden daarom ook wel een medicane genoemd; een samenstelling van Mediterranean Sea en hurricane (orkaan). Een medicane is vrij zeldzaam. De laatse medicane voor Ianos was Zorba, die in september 2018 over Griekenland trok.

De medicane kwam rond 5.30 uur aan in de westelijke kustregio. Eerder bracht Ianos al zware regenval en harde windstoten op Zakyntos, schrijft het Griekse nieuwsmedium Skai.

Naar verwachting trekt de storm vrijdag verder landinwaarts. Het is nog onzeker wat de koers van Ianos precies gaat zijn. Voor de zware weersomstandigheden heeft de Griekse weerdienst voor onder meer de regio Athene code rood afgekondigd.

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Zeldzame storm veroorzaakt grote overlast op enkele Griekse eilanden

Een klein deel van Griekenland heeft vrijdag door een zeldzame storm te maken met overstromingen, stroomstoringen en andere stormschade. Het gaat hierbij om een aantal eilanden voor de westkust.

Brandweerleden op Kefalonia, Zakynthos en Ithaka zijn druk in de weer om de overlast van storm Ianos te beperken. Ianos kwam daar met windstoten tot 110 kilometer per uur aan land. Woningen en wegen zijn beschadigd, maar er zijn geen gewonden gevallen.

Naast de Ionische Eilanden hebben ook plaatsen elders in het westen van Griekenland te maken met grote hoeveelheden regen en harde windstoten, maar de overlast lijkt daar tot nu toe beperkt te blijven. De wind neemt langzaam in kracht af. Volgens meteorologen is Ianos vooralsnog milder dan aanvankelijk verwacht.

Het is de verwachting dat Ianos vrijdagmiddag in het westen van het land blijft en in de loop van de avond verzwakt richting het zuiden trekt. Mogelijk krijgt ook het midden van Griekenland met de storm te maken voordat die zaterdag de regio rondom Athene bereikt.

De storm heeft tropische kenmerken en is boven de Middellandse Zee ontstaan. Soortgelijke stormen worden daarom ook wel een medicane genoemd: een samenstelling van Mediterranean Sea en hurricane (orkaan).

Griekenland kreeg in 1995 voor het eerst te maken met een medicane. In de afgelopen jaren komen deze stormen steeds vaker voor. De voorlaatste medicane was in 2018. Een jaar eerder kwamen 25 personen om het leven en raakten honderden mensen dakloos.

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“Ianos” was one of the most powerful Mediterranean cyclones since 1969

The phenomenon of “Ianos” was extreme, mainly in terms of rainfall, say the meteo scientists of the National Observatory of Athens (EAA) K. Lagouvardos, B. Kotroni and S. Dafis in a relevant publication on the website of the service. Indicatively, according to the network of meteorological stations of EAA / meteo.gr, 317 mm of rain were measured in Pertouli, while in Karditsa and Mouzaki more than 200 mm were measured in less than 24 hours. Comparatively, as they emphasize, the average annual rainfall in Athens does not exceed 400 mm. They also note the large geographical area that received high rainfall, resulting in an increased chance of flooding in these areas. Another extreme element of Janus was his long life with tropical characteristics and its intensity, which classify him as one of the most powerful Mediterranean Cyclones recorded since 1969, that is, from the beginning of satellite observations. The Mediterranean cyclone (medicane) is a deep barometric low, which draws its energy through the transfer of heat from the warm waters of the Mediterranean and the release of heat during storms near its center. A cloudless “eye” may appear in its center, similar to hurricanes, while its characteristics are hybrid, showing similarities to tropical and exotropic cyclones. According to EAA-meteo researchers, in the Mediterranean such barometric systems occur on average one and a half times a year, ie one to two Mediterranean Cyclones in a year, while other years may not be created. In the region of Greece, since 1982, six Mediterranean Cyclones have been recorded, four of which in the period 2016 – 2020. Although this is not an unprecedented weather phenomenon in our region, the growing trend of their occurrence during the last decade is a cause for concern. as well as increasing their intensity. The torrential rains in Thessaly and Anat. Solidly connected directly with Janus, according to the meteo. Janus functioned as a pump for extracting water vapor from the warm waters of the Mediterranean, transporting extreme amounts of water vapor high into the atmosphere. This saturated the atmosphere with water vapor and as a result there was rapid rainfall. In addition, Janos, in combination with the higher atmospheric pressures around it in the Eastern Mediterranean, significantly increased wind speeds, even away from its center. In addition, the convergence of gas masses that moved at high speed on the mountainous terrain of the central mainland, created the conditions for the formation of rain clouds and their stay in these areas for a long time. Finally, the prolonged duration of heavy rains in Thessaly and Central Greece are directly due to the slow movement of Janos on Friday and Saturday. The phenomenon was largely predictable, according to meteo, according to which “the only failure of the forecast was the rain in Athens at noon / afternoon on Friday 18/9, which were delayed by 12 hours”. To better monitor severe weather events such as Janos, researchers point out that there is know-how at the national level, but it requires investment in metering infrastructure and their completion in early warning systems. They also report the “lack of a national meteorological radar network for detailed weather monitoring, which will improve reaction time and extreme warnings.” Also, several more areas of our country should be covered with meteorological stations “.

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Doden door orkaan Ianos in Griekenland

De plaats Karditsa, 300 kilometer ten noordwesten van de hoofdstad Athene, werd zwaar getroffen, met modderstromen, omgewaaide bomen en stroomuitval. In die regio werd een boer dood gevonden op zijn boerderij.

Elders in die omgeving werd een vrouw gevonden die was verdronken in haar ondergelopen huis. Een derde slachtoffer wordt nog vermist, het is een automobiliste van wie de auto werd meegesleurd door het hoogwater in een rivier.

Noodsignaal migrantenschip
Er wordt op de Ionische Zee nog gezocht naar een schip met 55 migranten aan boord, dat vrijdag een noodsignaal uitzond. De Griekse kustwacht houdt er rekening mee dat het schip zijn koers heeft verlegd om de storm te ontwijken.

De orkaan ging gepaard met windstoten tot 117 kilometer per uur en zware regenval. Hij trof vooral het westen van Griekenland, waaronder de ook bij vakantiegangers geliefde eilanden Kefalonia en Zaynthos. Ianos wordt ook wel een ’medicane’ genoemd, een stormdepressie die tegen het eind van de zomer kan ontstaan op de Middellandse Zee, waar het water dan nog warm is.