Europe: Euro-forecaster Estofex issues Level 2 Storm Forecast for N Italy – Published 290614 1700z

Storm Forecast

Forecast provided by ESTOFEX (Click image to go to source)

Storm Forecast
Valid: Sun 29 Jun 2014 06:00 to Mon 30 Jun 2014 06:00 UTC
Issued: Sun 29 Jun 2014 04:22
Forecaster: VAN DER VELDE

A level 2 was issued for N Italy mainly for severe convective wind gusts, large hail and excessive convective precipitation.

A level 1 was issued for parts of central Europe mainly for large hail.

SYNOPSIS

The cold front associated with a large amplitude mid level trough from Scandinavia to the Mediterranean Sea is pushing eastward through Italy and central Europe today. Surface level lows reside over southern Scandinavia and northern Italy. Cold airmass thunderstorms are likely over France, Benelux and western Germany. The prefrontal airmass over Italy is moderately unstable due to the presence of the Saharan Air Layer with steep mid level lapse rates and 10-12 g/kg moist boundary layer air. Strong winds in mid levels create a favorable kinematic environment for storms.

DISCUSSION

…Italy, southern Austria and western Balkan…

Some regional WRF models predict over 2500 J/kg SBCAPE over the Lgurian Sea. MLCAPE should be 1000-2000 J/kg. This will be capped south of the Po valley. Either way, given the 20 m/s deep layer shear and strong moisture lifting over the south slopes of the Alps triggering of supercells and MCSes is highly probable, with chances of widespread large to very large hail and severe wind gusts. During the evening as the cold front comes through, the model scenario (GFS, WRF) is that some discrete supercells or a linear system will also affect the area south of the Po valley. The area of Austria to Croatia will likely see the strongest moisture lift and largest storms, and can become affected by excessive convective rainfall, at least locally. The PV/dynamic tropopause intrusion acquires a negative tilt at night which might help to keep the storms active for long in the region near Slovenia, although WRF models keep the storms moving. Tornadoes are not ruled out with pre-Alpine 0-1 km shear of 8 m/s and locally higher.

…Hungary, N and E Austria, Czechia, Slovakia, Poland, Lithuania…

Relatively modest MLCAPE should exist in a broad area from Hungary/Austria to the Baltics. The presence of 10-15 m/s deep layer shear could develop persistent and rotating updrafts which can locally release large hail. The frontal convergence zone in the Austrian-Hungarian-Czechian borders region should be the main focus for convective development, another is NE Poland and Lithuania near the occlusion.

…southern Sweden and Norway…

Some instability is present within the low. Low cloud bases and slow cell motion combined with good low-level buoyancy and convergence zones are found mainly over southern Sweden. Such conditions are favorable for spout type tornadoes and funnels.

ESTOFEX FAQ

France: Euro-forecaster Estofex issues Mesoscale Discussion – potential for tornadoes – Published 280614 1638z

Mesoscale Discussion

Mesoscale Discussion
Valid: Sat 28 Jun 2014 14:00 to Sat 28 Jun 2014 21:00 UTC
Issued: Sat 28 Jun 2014 14:39
Forecaster: VAN DER VELDE

…France to Southwestern Germany…

A surface low pressure center lies currently (14Z) at the west coast of France (Bordeaux). A large Atlantic upper trough moves into the region and will provide destabilization of the mid and upper levels, which is needed as 12Z soundings still show inversions at 900 and 450 hPa. A stationary frontal zone is well-defined by thermal gradients and a sharp wind shift (NE/S) running from some 100km north of Bordeaux to Stuttgart approximately.

Observed surface mixing ratios in France vary at 13Z between 10.5 and 13 g/kg with potential temperatures ranging between 26 and 32ーC, the higher values over the Massif Central.
Inserting these values into Bordeaux and Nimes 12Z soundings, the cap can be bypassed in some locations and some 1000 J/kg SBCAPE could be obtained, but MLCAPE will be lower and mixed parcels may have some trouble with the cap.

In fact, satellite shows initiation over northern Massif Central oriented SW-NE and along the front in the west (WSW-ENE). The storms will grow in a strong kinematic environment with large but relatively straight hodographs. Observed Bordeaux 600 hPa wind is 60 kts with 40 kts at 900 hPa. This directly translates into a primary threat of severe convective wind gusts, especially as cold pools join into an MCS. Deep layer shear values of 15-20 m/s and SREH of 150 mイ/sイ initially and over 250 mイ/sイ predicted by GFS at 18Z (SW France) support supercells. 0-1 km shear ranges from 10 m/s in the afternoon to over 15 m/s during the evening (GFS). Together with relatively low LCL (descending to <1000 m in the evening) this underlines potential for tornadoes, and supports bow echoes. Large hail will be possible as well, but the upper level inversion represents a mixed phase region without much buoyancy which could be a limiting factor.

After 18Z the mid level cold front comes in from the west and will likely trigger storms in SW France moving upscale to a somewhat parallel-stratiform MCS over the southeastern quarter of France (this will happen beyond the validity time of this MD).

Europe: ESTOFEX Storm Forecast: Level 1 for parts of France, Benelux, Germany, Italy and Iberia valid until 241013 0600Z. Tornadoes, Heavy rain and hail possible – 231013 1348z

Storm Forecast

Storm Forecast
Valid: Wed 23 Oct 2013 06:00 to Thu 24 Oct 2013 06:00 UTC
Issued: Tue 22 Oct 2013 21:15
Forecaster: PUCIK

A level 1 was issued for Central France, BENELUX and Northwestern Germany mainly for tornadoes and severe wind gusts.

A level 1 was issued for Southern France and Northern Italy mainly for excessive precipitation and tornadoes.

A level 1 was issued for Western Iberia mainly for excessive precipitation.

SYNOPSIS

General macrosynoptic pattern will remain more or less the same as during the previous days – a broad southwesterly flow is forecast over much of Western and Central Europe situated between deep trough over the Atlantic and ridge over Eastern Europe. This trough will translate towards northeast, slightly de-amplifying the ridge but no major reconfiguration is expected. Unseasonably warm airmass has spread all the way up to Southern Scandinavia, while a weak CAA is expected behind the insignificant cold front that will move from France towards Germany. Another significant trough will approach the Iberian penninsula towards the Thursday morning hours.

DISCUSSION

… Central, NE France, BENELUX, NW Germany …

With cooler, moist airmass overspreading the region, low LCLs are forecast. Only moderately steep mid-level lapse rates will very likely limit the instability build-up, so that only few hundreds J/kg of CAPE are expected at best. Strong, unidirectional wind shear is simulated, with much of the shear within the lowest 1 km, yielding LLS values between 10-15 m/s in the region. With the belt of enhanced PV approaching the area, scattered DMC will initiate. In the strong shear regime, low-topped supercells are well possible, capable of severe wind gusts, tornadoes or some mostly sub-severe hail.

… S France, N / NW Italy ….

In the strong southwesterly flow, a belt of steep mid-level lapse rates is forecast to advect over the Mediterranean Sea along with moist low-level airmass. Moist flow experiencing uplift near the coastline or near the Alps will likely initiate widespread DMC – possibly featuring one or more MCS. In case of the training pattern, moist conditions might enhance precipitation efficiency and locally excessive rainfall is expected. Threat will shift from Southern France towards Northern Italy. MCS will likely start building southwards towards the unstable airmass during the Wednesday night hours. Enhanced low level shear near the coastline along with low cloud bases also point at the elevated tornado risk in the region, albeit this threat should be less prominent than the precipitation risk.

… W Iberia …

During the late afternoon / evening hours, tongue of moist and unstable airmass ahead of the trough is expected to initiate widespread DMC near the coastline. With strong low level convergence and enhanced mixing ratios, isolated excessive precipitation event is quite possible. Tornadoes can not be ruled out in this setup with stronger low level shear inland, albeit CAPE here will be likely mostly elevated, thus possibly rendering this shear ineffective.

Related:

Severe Weather Warnings for Europe. Orange Alerts for Switzerland, France, Italy and Netherlands http://www.meteoalarm.eu

France: ESTOFEX Storm Forecast: Level 1 for parts of France valid until Sun 201013 06:00Z. Isolated tornado events, Heavy rain, large hail possible – 191013 1325z

Storm Forecast

(Scroll down for French translation) (Faites dfiler vers le bas pour la traduction franaise)

 

 

Storm Forecast
Valid: Sat 19 Oct 2013 06:00 to Sun 20 Oct 2013 06:00 UTC
Issued: Fri 18 Oct 2013 16:17
Forecaster: TUSCHY

 

A level 1 was issued for parts of C France mainly for isolated large hail, excessive rain and an isolated tornado event.

A level 1 was issued for a small part of S France mainly for isolated large hail and an isolated tornado event.

SYNOPSIS

A flat and transient omega-like pattern has established over Europe. A weakening upper trough over SE Europe remains in place with only a low-end motion to the east. Numerous vortices over the far E-Atlantic steer a warm/humid air mass far to the NE while a stout branch of the polar vortex over N-Norway/Sweden advects a cold airmass to the south. A deep baroclinic zone (e.g. in excess of 20 K difference at 500 hPa between Germany/N-Norway) is the result with an evolving 40 m/s mid-level streak over the Baltic Sea.

This kind of pattern results in a bisection of Europe from the North Sea to Greece. Areas to the east will feel the influx of cool/cold and dry continental air from the N whereas areas to the west see a gradual recovery of moisture, both due to advection of a modified subtropical air mass and a moistening W-Mediterranean air mass. Hence thunderstorm probs. over E/NE Europe remain confined to offshore and coastal areas with isolated/weakly electrified storms. Scattered and stronger storms however occur over far W Europe.

DISCUSSION

… Ireland and United Kingdom …

Ingredients for thunderstorms will be in place with some iffy signals however. Behind a ENE-ward moving front (already transforming from a cold front into an occlusion from N to S) seasonable BL moisture remains in place. Mid/upper jets also reveal a good placement for some lift in addition to a weak vort.max. crossing the area of interest from SW to NE between 12-18Z. However, forecast soundings show a meager depth of the BL moisture with constant drying above. Therefore onshore turbulent mixing next to some temporal heating lower confidence in adequate CAPE build-up well inland. Coastal areas (SW-ward facing) will see best moisture and at least 300 to 700 J/kg SBCAPE. Some veering in the lowest 2 km AGL is present along the coastal areas with 50-100 J/kg 0-3 km CAPE, so an isolated spout/short-lived tornado is possible. Effective PWs also approach 20 mm, which could lead to some heavy rain and 15-20 m/s 850 hpa flow should ensure gusty winds with stronger convection.

We expanded the lightning areas far offshore. Despite more hostile conditions for electrified storms with this type of air mass, approaching cooler mid-level air should increase the CAPE disperal in the mid-level graupel layer a bit. Hence confidence in more activity compared to yesterday has increased.

We also splayed the eastern part of the 15-% lightning area all the way to Denmark to cover a few elevated thunderstorm events beyond 12Z. This also includes parts of N France . This activity will be non-severe.

… S/C-France …

Odds increase to see an heavy and convectively enhanced rainfall event between Marseille and Montpellier .

A very moist air mass is in place over the far W-Mediterranean with no serious frontal intrusion forecast. Persistent SW-erly mid/upper flow and falling surface pressure to the W/NW should assist in a constant onshore flow and hence better onshore moisture over the area of interest.

However, position and strength of the mid/upper jets are not yet favorable during most of this forecast period but improve after midnight. The same with the LLJ, which showes some strengthening during the overnight hours. Hence, expect mainly onshore convection during daytime hours.

We issued a 50-% lightning area and a level 1 as persistent upslope flow towards the Massif Central could induce a cluster with isolated large hail (20 m/s DLS).

We also don’t want to exclude an isolated tornado event with LCLs below 1 km and enhanced LL shear. Interaction of mid/upper dynamics and aforementioned LLJ could also support a temporal back-building with excessive rain the main risk. Therefore the level 1 was expanded far inland.

Beyond 00Z, environmental conditions improve for a developing coastal cluster with back-building tendencies. With 20-25 m/s DLS and increasing SRH, any coastal storm should become organized and probably supercellular. Large hail and an isolated tornado will be the main hazards.

Current thoughts with late development of that cluster preclude an excessive rainfall – level issuance for now. In case of earlier CI, excessive rain will be added to the current level 1 wording.

French (Translated by Google)

tempête Prvisions

tempête Prvisions
Valable : sam 19 octobre 2013 06h00 à Sun le 20 octobre 2013 06:00 UTC
Publi : Vendredi 18 octobre 2013 16:17
Prvisionniste : TUSCHY

Un niveau 1 a t mis pour une partie de C France principalement pour de la grosse grêle isol, l’excès de pluie et une manifestation de tornades isoles.

Un niveau 1 a t dlivr pour une petite partie de S France principalement pour isol gros grêlons et une manifestation de tornade isol.

SYNOPSIS

Un modèle plat et transitoire omga -like a mis en place en Europe. Un affaiblissement creux en altitude sur l’Europe du Sud reste en place avec seulement un mouvement de bas de gamme à l’est. De nombreux tourbillons plus loin le E- Atlantique dirigent une masse d’air chaud / humide loin au NE tandis qu’une grosse branche du vortex polaire sur N-Norway/Sweden advecte une masse d’air froid vers le sud. Une zone barocline profonde (par exemple au-delà de 20 diffrence de K à 500 hPa entre l’Allemagne / N- Norvège) est le rsultat d’un 40 m / s volutive srie à mi-niveau sur la mer Baltique .
Ce genre de rsultats de motif dans une dichotomie de l’Europe à partir de la mer du Nord à la Grèce. Rgions à l’est se sentiront à l’afflux de froid / froid et sec air continental de la N tandis que les zones à l’ouest voient une reprise progressive de l’humidit , à la fois en raison d’ advection d’une masse d’air subtropical modifi et une masse d’air W -mditerranenne d’humidification . D’où probs orage. sur E / NE Europe de rester confine à des zones extractières et ctières avec isol / tempêtes faiblement lectrifies. pars et plus forts orages se produisent cependant plus loin W Europe.

DISCUSSION

… L’Irlande et le Royaume-Uni …

Ingrdients pour les orages seront mis en place avec certains signaux iffy cependant . Derrière un front mouvant ENE- Ward ( djà transformer à partir d’un front froid dans une occlusion de N à S) humidit BL de saison reste en place. Jets milieu / haut rvèlent galement un bon placement pour certains ascenseur en plus d’un vort.max faible. traversant la zone d’intrêt du SO vers le NE entre 12 – 18Z . Cependant, les sondages de prvisions montrent une profondeur maigre de l’humidit BL avec schage constante au-dessus . Par consquent onshore mlange turbulent à ct de certains chauffage temporal infrieur confiance suffisante CAPE accumulation et l’intrieur des terres . Les zones ctières (face SW- Ward) verront mieux l’humidit et au moins 300 à 700 J / kg SBCAPE . Certains virant au moins 2 km AGL est prsent le long des zones ctières 50-100 J / kg 0-3 km CAPE , si une tornade bec / courte dure isole est possible. PG efficaces abordent galement 20 mm , ce qui pourrait conduire à une forte pluie et 15-20 m / s 850 hpa dbit devrait assurer des rafales de vent à convection forte.

Nous avons largi les domaines de la foudre loin des ctes . Malgr des conditions plus hostiles pour les tempêtes lectrifies avec ce type de masse d’air , approchant refroidisseur d’air de niveau moyen devrait augmenter le CAPE Disperal dans la couche graupel mi- niveau un peu. D’où la confiance dans plus d’activit par rapport à hier a augment.

Nous avons galement vase de la partie orientale de la 15 – % de la superficie de l’clair tout le chemin au Danemark pour couvrir quelques vnements d’orage levs au-delà de 12Z . Cela inclut galement des parties de N France. Cette activit sera sans gravit .

… S / C- France …

Les chances augmentent de voir un vnement de pluie abondante et convection renforce entre Marseille et Montpellier.

Une masse d’air très humide est en place sur l’extrême W -mditerranen sans grave prvisions intrusion frontal. Persistent SW -rectement mi / dbit suprieur et chute de la pression de surface à l’ W / NW devrait contribuer à un flux constant onshore et l’humidit donc mieux à terre sur la zone d’intrêt . Toutefois, la position et la force des jets milieu / haut ne sont pas encore favorable pendant la majeure partie de cette priode de prvision mais s’amliorent après minuit. La même chose avec le LLJ , qui showes un renforcement pendant les heures de nuit . Par consquent, s’attendre à convection principalement à terre pendant la journe . Nous avons mis un 50 – zone de foudre % et un niveau 1 en coulement ascendant persistant vers le Massif Central pourrait induire un cluster avec de gros grêlons isol ( 20 m / s DLS ) . Nous ne voulons pas exclure un vnement de tornade isol avec LCL en dessous de 1 km et un cisaillement accru LL . Interaction des dynamiques milieu / haut et LLJ susmentionn pourrait galement soutenir un arrière – btiment temporelle avec l’excès de pluie , le risque principal . Par consquent, le niveau 1 a t tendu loin dans les terres .

Au-delà de 00Z , les conditions environnementales s’amliorent pour un cluster ctier en dveloppement avec des tendances arrière – btiment. Avec 20-25 m / s DLS et l’augmentation de la SSR , une tempête ctière doit s’organiser et probablement supercellular . Gros grêlons et une tornade isol seront les principaux dangers. Rflexions en cours avec le dveloppement tardif de ce cluster empêcher un excès de prcipitations – mission de niveau pour l’instant. En cas de CI plus tt , l’excès de pluie sera ajout à l’ actuel libell de niveau 1 .

Saudi Arabia: Chaos as flash floods and hail leave 14 dead; many accidents reported; 937 rescued from homes & cars – 010513 1700z

Fourteen people have died and four are missing due to torrential rain, said the Saudi Civil Defense General Directorate.
From Monday night until midday Tuesday, Saudi authorities received more than 4,213 reports from across the kingdom of accidents resulting from torrential rainfall.
Classes have been suspended in affected areas of the country.
Civil Defense forces said they have saved more than 937 people trapped in their homes and cars, and have housed and helped more than 695 families.
There have been 307 reports of traffic accidents and people trapped in their cars, but no fatalities have been recorded in these incidents.
Wednesday, 01 May, 2013 at 11:33 (11:33 AM) UTC RSOE

Riyadh Floods


Flash floods in Saudi Arabia

(Video credit: kuya Bhagz)

News Reports

Flash floods in Saudi Arabia leave 13 dead

BBC

Floods in Saudi Arabia Saudi authorities have been criticised in the past for a lack of preparedness for floods

At least 13 people have died and four other are missing in flash floods in Saudi Arabia.

Deaths were reported in the capital Riyadh, Baha in the south, Hail in the north and in the west of the country

The Saudi Civil Defense Authority urged people to avoid valleys and plains that have been flooded by the heavy rainfall that began on Friday.

Saudi television showed footage of people clinging to trees and cars trapped by water.

The rain is said to be the heaviest experienced by the desert kingdom in more than 25 years.

Map

On Sunday the Saudi Interior Minister Prince Mohammad Bin Nayef called on civil defence authorities to coordinate their efforts and provide assistance to people affected by rain and flooding. The minister was described by a spokesperson as “closely monitoring the situation”.

Saudi authorities have been criticised in the past for lack of preparedness in coping with flooding. Flash floods in the Red Sea port of Jeddah killed 123 people in 2009 and 10 in 2011.

The inability of Jeddah’s infrastructure to drain off flood waters and uncontrolled construction in and around the city were blamed for the high number of victims in 2009.

At the time King Abdullah promised action saying “we cannot overlook the errors and omissions that must be dealt with firmly”.

However critics have said that despite the promises little has been done to alleviate the dangers posed by flash floods.

China: Hail storm leaves 3 dead, 200 homes collapsed, 11,000 damaged & 9,400 evacuated in Hunan Province. More forecast – 200413 1520z

(Photo: chinadaily.com.cn/Teng Zhizhong/Asianewsphoto) Dongkou, Hunan province, April 18, 2013

Hailstorms have battered parts of central China’s Hunan Province since Thursday, leaving three people dead, local authorities said Friday.
According to Hunan’s Provincial Department of Civil Affairs, the hailstorms have affected 105,000 residents and forced the evacuation of more than 9,400 people.
Nearly 200 houses collapsed and 11,000 houses were damaged to varying degrees.
The storms have also destroyed about 3,900 hectares of crops. Hailstones were as large as 1.8 cm in diameter in the city of Jishou.
Wind speeds hit 22.6 meters per second at Hengshan Mountain, a renowned scenic area.

Weather forecasts said heavy rain and hail will continue to hit parts of Hunan next week.
Friday, 19 April, 2013 at 17:27 (05:27 PM) UTC RSOE

Related:

Severe Weather Warning (China Weather Bureau)

China currently dealing with major earthquake aftermath

China: Major Sichuan earthquake kills at least 100, over 600 injured 2004130850z