Italia

Severe Storm

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forecast valid from 00:00 until 23:00 on Friday 2 August

Synoptic

A frontal system, inserted in an intense western flow present in free atmosphere, will pass during the day tomorrow on the north of Italy determining a full-bodied worsening of the weather, with hail, flooding and gusts of wind.

The deterioration will be divided substantially into two phases.
The first, from night until early afternoon, with prefrontal thunderstorms that will ride the ascending branch of the jet streak (movement from west / south west to east / north east).

The second, from early afternoon until the evening, with frontal thunderstorms that will affect larger areas but which will be less organized.

The most stringent parameters will be localized in the first phase, in fact we estimate, despite the night / morning hours, peaks on the 2100J / kg of Cape (energy available at the convection), shear (variation of direction and intensity of the wind with the altitude) on 20-25m / s and good values ​​of energy helicity that will favor the formation of organized systems and supercells

The frontal phase will instead see a greater entry of cold air at altitude but a simultaneous collapse of parameters such as shear and a drop in the jet.
Multi-cell or Mcs thunderstorms will be favored.

Lombardy, Veneto, Friuli Venezia Giulia, Emilia Romagna and Trentino

Very active prefrontal phase between middle high plains and Alpine area (level 2-3). The thunderstorms will develop over Lombardy in the very early hours of the night, evolving towards Veneto, Trentino and Friuli, resulting organized and with the possibility of long-lasting supercells, especially between Veronese, Vicentino, Padovano, Veneziano, Rodigino and Trevigiano, where, in the morning, it will be established a convergence between Bora and Scirocco.

In fact, despite the night / morning hours, Cape values ​​are estimated at around 2100J / kg, with the possibility of medium to large hailstorms (> 3cm), flooding, with discomfort and gusts of wind.

The frontal phase will instead be more active in the middle low plains (Emilia Romagna and Veneto border).

The entry of cold air at altitude will allow the development of many thunderstorm cells, but the simultaneous collapse of the shear will determine the evolution of multicellular-cluster or Mcs (mesoscale convective system) thunderstorms.

The areas affected by heavy rain, hail and downburst with gusts above 100km / h will be considerable, with probable inconvenience.
PAY ATTENTION

Piedmont, Valle d'Aosta and Liguria

Prefrontal phase that will determine some thunderstorms between Alto Piemonte and Valle D'Aosta but rapidly evolving towards the east.

Afternoon frontal phase that will be more active on the mid-low plains, especially between Langhe and Monferrato, where the formation of multicell clusters will be possible.

Despite the level 1 emitted, the very high Cape values ​​(peaks up to 2500J / Kg) make medium-sized hailstorms and wind blows possible.
Possible thundering storms also attenuated along the Ligurian coast, especially in the stretch between Andora and Genoa.

Marche

Although not shown on the map, an obligatory citation for the northern area of ​​the Marche bordering Romagna.
Between afternoon and evening he will find himself on the southern edge of the disturbance, thus keeping shear on high values ​​and at the same time a good convergence of winds to the ground.
In this area it will be possible to form one or two supercells, with the possibility of hailstorms.

Jacopo Zannoni

The member of the storm chasers group ZenaStormChaser from Genoa, Italy. Follow ZenaStormChaser on Facebook, Instagram or Twitter

forecast valid from 06.00 to 23.59 UTC on Friday 26 July

The hegemony of the North African high pressure ends under the blows of an imposing Atlantic perturbation that will literally break through, with its load of cold air, from the western quadrants, determining a perturbed weekend on most of Italy.

At the end of this summer break we will certainly count the damage for very violent phenomena.

Tomorrow will see a first baric collapse with thunderstorms mostly for relief purposes.

The jet stream (current of air present in free atmosphere that "transports" thunderstorms) will tend to dispose from west / south west with sharp and sudden destabilization of the air column

The abnormal energy in play will facilitate the formation of violent thunderstorms with the possibility of medium-large hailstorms.

Veneto, Friuli Venezia Giulia e Emilia Romagna

Thunderstorms that will develop during the early afternoon on the alpine reliefs. South-eastern ventilation on the lower Veneto will drag energy values ​​(Cape) between 2500 and 2800 J / kg up to the Alps, with a serious risk of high intensity phenomena (Level 2-3 Alpine area). Indeed, storms, floods, landslides and medium-large hailstones are likely to occur. We strongly advise against outings especially on the exposed ridges.

The storms will move from west to east, affecting the entire Alpine and pre-Alpine area of ​​Friuli by late evening.
Trespassing on the high plains is not excluded.

Between late afternoon and evening, some parameters pushed to the limit suggest a sudden trigger in the middle of the plain on the border between Emilia and Veneto.

On these areas a convergence will take place between the humid south-east rising from the Adriatic and the drier sw from the Apennines, towards evening the outflow of the alpine storms could even create a triple point of convergence.

The trigger at high altitude to trigger this bomb ready to jump appears really bland but if it were to trigger, the storm would find an abnormal energy to be exploited with peaks above 3000J / kg and the possibility of large hailstones (> 5 cm), flooding and Tornado

P.Š. Only level 2 was issued due to doubts about the trigger, possible raising to 3 in case of further confirmation by the models.

Alps (Level 1) And appennines

Afternoon phenomena with hail and in some cases local flooding, local and temporary trespassing on the neighboring plains are not excluded.

Jacopo Zannoni

The member of the storm chasers group ZenaStormChaser from Genoa, Italy. Follow ZenaStormChaser on Facebook, Instagram or Twitter

850 hPa temperature anomaly

As already mentioned in the previous article, here we are dealing with another heat wave that will push the accelerator from tomorrow. Warm air will reach Portugal, Spain, France and Italy with peaks up to +27 degrees at an altitude of 850hpa (1500m) on the Iberian peninsula.

In France, Spain and inland areas of Portugal the temperature will exceed + 40 ° on the ground, while in Italy it will stop around + 35 °.

In the following days (Tuesday / Wednesday) the hot air will tend to invade even central Europe and Scandinavia, on the latter, peaks are expected around + 20 ° at 850hpa.

In short, hot that will reach almost all of central-western Europe, resulting particularly intense in Spain and France, where people's health will be at risk.

The anticyclone responsible for all this will initially have a double supply. Let me explain better, the hot air will flow both from Africa and from the tropical Atlantic (anticyclone of the Azores) thus forming a very strong hybrid structure.

Dual power anticyclone (Azores and Africa)

Subsequently with the further sinking towards the south of the low-pressure structure in the open Atlantic, the high pressure will lose the Atlantic feeding, but further increasing the push by the African hot air.

Between Thursday and Friday, the freshest oceanic winds will begin to blow on Portugal and northern Spain and on western France with thunderstorms also of strong intensity.

Italy will have to wait for Saturday / Sunday.

This medium-long term option appears more likely for areas facing the Atlantic Ocean while for other areas confirmation will be needed in the coming days.

The Scandinavia will live a very long period of thermal supremacy due to the isolation of an anticyclonic structure on the peninsula (scand +).

Jacopo Zannoni

The member of the storm chasers group ZenaStormChaser from Genoa, Italy. Follow ZenaStormChaser on Facebook, Instagram or Twitter

Here we are, after this period dominated by the fresh Atlantic currents coming from the north-western quadrants, another heat wave is ready for Europe, especially the central western one.

Mathematical models in fact begin to frame a clear and decisive rise in the tropical bands starting from 140 hours, with a leveling of the tropical strips over most of Europe and a polar jet that tends to flow very north of latitude.

Unlike the last heat wave, which was very strong but of ephemeral duration, which occurred during the month of June, we are faced with a real anticyclonic wall that will rise to protect Europe without the help of a dynamic forcing (see the intense depression that was present on the Portuguese Atlantic in June).

This leveling of the tropical bands between the ocean and the continent represents the topical moment of summer, the most lasting and intense stable phase that could be for at least 15 days.

To support the thesis of this new heat wave are:

1. a very intense African monsoon and 2) a consequent Itcz (intertropical convergence line) placed at more northern latitudes than the average.

An itcz in a higher position provides a greater thrust to the hadley cell making it easier to extract the tropical anticyclonic belt to the north.

Summer will therefore return to raising its voice, bringing a long period of stability and a clear increase in temperatures.

Jacopo Zannoni

The member of the storm chasers group ZenaStormChaser from Genoa, Italy. Follow ZenaStormChaser on Facebook, Instagram or Twitter

Forecast valid for Tuesday 16 July from 00:00 until 23:59 utc

Synoptic

The cold drop, which during the day has affected and is still affecting the Italian central north, moves quickly towards the south, causing a worsening of the weather even in the south Italy.

The cyclonic vortex will find areas along its path with still a discrete "fuel" convertible into thunderstorms and heavy rains. In fact, peaks of 1600J / kg are expected, especially between Calabria, eastern Sicily and the Ionian Sea.

Molise and Puglia

The thunderstorms will move from north-east (Adriatic sea) towards south-west, in fact these regions will be located on the north-eastern edge of the low-pressure structure, and will be more intense between Molise, Foggiano and the province of Barletta Andria Trani, with local accumulations significant and flooding ( level 2).

Elsewhere more isolated thunderstorms. Waterspouts will be possible both on the Adriatic and Ionian sides of Puglia thanks to the presence of a strong helicity in the first km of atmosphere.

Calabria and Campania

On Campania, thunderstorms will tend to develop in the next few hours, resulting very intense in the central-southern part of the region.

During the night and during most of the day tomorrow a stormy corridor will be created from the Tyrrhenian towards the Ionian Sea that will cross practically all of Calabria (levels 2-3).

The most intense thunderstorms will hit the open sea but flooding along the coasts caused by the huge rainfall accumulations cannot be excluded.

The high helicity values ​​in the first km of atmosphere will favor the formation of waterspouts especially on the Tyrrhenian side.

Sicily and Basilicata

These two regions will be found respectively in the south-west and north-east of the storm channel that will hit Calabria.

Phenomena of moderate intensity will be possible but no inconvenience is expected.

A little more detail for Sicily, where, once again under a strong jet stream, thunderstorms will be more organized but also more mobile.

Jacopo Zannoni

The member of the storm chasers group ZenaStormChaser from Genoa, Italy. Follow ZenaStormChaser on Facebook, Instagram or Twitter

Forecast valid from Sunday 14 July to 21:00 until 23:59 of Monday 15 July 2019

Synoptic

A small cold drop in the next few hours will approach the western Alps determining, from today's late evening, rains and thunderstorms over most of northern Italy.

Subsequently, the translation towards the south-east of the same, will determine strong thunderstorms on the Tyrrhenian, Corsica and Tuscany with flash flood risk for different areas.

Thunderstorms will often be stationary causing hydrogeological stress conditions, due to the low jet present at high altitude and the little mobile convergences that will be established here and there on the Italian western basins.

Even Sicily will see relevant phenomena, in fact it will be dominated by a branch of the jet streak with intense thunderstorms moving from west to east ..

Piedmont, Lombardy and Emilia Romagna

Rains and thunderstorms that already from the late evening of today will affect the high plains but that during the night and morning will tend to conquer the lowlands.

The greatest risks will derive from the accumulations, locally very high, with the risk of flooding and inconvenience. Western and southern Piedmont and Emilia Romagna are under observation.

The continuous rains with the passing of the hours will replace the thunderstorms due to the lack of energy available to the convection

Liguria, Tuscany, Corsica and Sardinia

An intense south-east flow will blow from the Tyrrhenian Sea up to the Ligurian gulf carrying with it a fair amount of energy (up to 1500J / kg).

Just on the gulf a clear convergence will be established, already in the early hours of the day, between the north wind that will devalue from the Ligurian Apennine passes and the sirocco rising from the south east, with very violent thunderstorms that will mainly affect the open sea and the finger of Corsica (level 3).

There should be no major risks to the Ligurian coast with phenomena "filed" by the presence of the north wind in the lower layers.

Also in the morning strong storms will affect the island of Elba and southern Tuscany, with risk of flash floods and severe traffic disruptions.

In this area, thunderstorms will persist in alternate phases until the late afternoon hours, with the possibility of waterspout also trespassing along the coasts, be careful.
Some phenomena will also affect the North of Sardinia but no criticalities are expected.

Sicily

This region will be crossed by a branch of the jet streak with clear and sudden destabilization of the air column. The first thunderstorms will be formed on the north of the island during the early afternoon resulting immediately intense (level 2-3).

The phenomena will ride the jet stream, moving rapidly to the east and also affecting the eastern areas of the island by evening.

Also in this case the greatest risks will derive from the huge accumulations. The hailstorms will be at most medium-small size.

Jacopo Zannoni

The member of the storm chasers group ZenaStormChaser from Genoa, Italy. Follow ZenaStormChaser on Facebook, Instagram or Twitter

Forecast valid on Saturday 6 July 2019 from 06:00 to 23.59 Utc

Busy days await Northern Italy, with two different disturbed structures that will meet right next to the Italian north.

During the day tomorrow a cut off on the Iberian peninsula will determine the establishment of an intense flow from west to north-west in free atmosphere.

Northern Italy will find itself in the limbo between very hot North African air and fresher puffs that will tend to cross the Alps, thus favoring the formation of very intense thunderstorms.

The energy available for convection will be really high with peaks of over 3,000J / kg that will go as far as the Alpine areas transported by an important low-jet jet from the south-east. The shear will also be very high, favoring the formation of highly organized thunderstorm structures and therefore supercells.

Friuli Venezia Giulia and Veneto

Thunderstorms forming during the afternoon hours on the alpine mountains with the risk of large hailstorms and flooding, we strongly advise against mountain excursions (Level 2 and 3).

The phenomena will tend to evolve towards the Friulian and eastern Veneto plains, with the possibility of supercells.
Due to the intense south-east ventilation present on the ground, combined with a Cape (energy available for thunderstorms) expected beyond 3000J / kg, vortex phenomena cannot be excluded.

In late evening / night on Sunday, possible intense thunderstorm passage with Verona / Vicenza axis towards Venetian Padua and Rovigo, but given the time it will fall in the outlook for Sunday, also for this reason only one level 1 has been issued.
We invite you to pay attention.

Lombardy, Piedmont and Trentino Alto Adige

Mostly late afternoon and evening phenomena relegated to the Alpine belt with the risk of medium-sized hailstones and local discomforts due to flooding, especially between Como and Lecco (LEVEL 2).

Towards midnight possible extension of the phenomena towards the plains, with cape (energy available for thunderstorms) that will remain really high despite the night hours, with peaks up to 2500J / Kg.

Also in this case, being beyond midnight, it will fall within Sunday's outlook, for this reason only one level 1 has been issued.

Jacopo Zannoni

The member of the storm chasers group ZenaStormChaser from Genoa, Italy. Follow ZenaStormChaser on Facebook, Instagram or Twitter

massive storm expected in italy

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Forecast valid for Wednesday 3 July 2019 from 06:00 to 23:59 utc

One more unpredictable day but with high potential, with the possibility of forming strong thunderstorms, gusts of wind and hailstorms.
A very mild wave cable will in fact pass through northern Italy during the afternoon / evening.

The slightest drop in geopotentials combined with vorticity injection will result in the formation of multicellular storms and given the energy involved (peaks of 3000J / kg) also MCS (Mesoscale convective system).

The MCS are a mass of multicells with a duration of at least 3 hours, an extension of more than 150km and with top of the cloud that must reach certain temperature values.

Initially a very strong cap will be present on the plain but analyzing the theta e at 850hpa (about 1500m) and the curvature at 700hpa (about 3000m) it seems very probable the explosion of the convection that will literally blow up this cap.

Valle d'Aosta and Piedmont

Phenomena in formation during the afternoon hours on Alpine and Apennine reliefs. The most intense thunderstorms could hit the lower Piedmont on the border with Liguria with hailstorms and gusts of wind. Elsewhere more sporadic phenomena. Possible trespassing between Genovesato and Savonese but with phenomena of the most weak intensity

Veneto, Lombardy and Emilia Romagna

Some phenomena will be present on the upper Veneto already in the morning but the highlight of the phenomena will be between afternoon and evening.

The areas within level 2 will be those that will risk the most, with the possibility of Mcs (mesoscale convective system) and annexed hail of medium large dimensions and gusts of wind (downburst), with an intensity even higher than 100km / h.

The motion of thunderstorms will be random and guided by the winds of outflow (cold wind coming out of thunderstorms) but tend to tend to move from west to east.
Beware of hail which in some cases may exceed 4 cm in diameter.

Friuli and Trentino Alto Adige

Still under observation the alpine area with some phenomenon already in the morning and subsequently also during the afternoon, hail and very high rain rates with local inconveniences are not excluded.

Attention for those who practice mountain tours.

Jacopo Zannoni

The member of the storm chasers group ZenaStormChaser from Genoa, Italy. Follow ZenaStormChaser on Facebook, Instagram or Twitter