Aviso do Estofex para hoje dia 1 De Novembro de 2008 na Europa:
A large upper trough over southwestern Europe will be the main focus for convective activity on Saturday. Ahead of this trough, very moist and unstable air is advected into parts of Italy and the Aegean / Ionian Sea ahead of a well-defined cold front. Surface winds are forecast to weaken as the pressure gradient decreases due to an occlusion process. A very strong southwesterly upper flow with wind speeds in order of 30 - 40 m/s at 500hPa will persist over the whole western / central Mediterranean. Severe weather should become more likely in the western Mediterranean on early Sunday morning as the upper trough overspreads a region with SSTs around 20°C.
...Central Mediterranean, Balkans, Aegean Sea...
The cold front over the central Mediterranean, associated with a small surface low over Italy, will translate northeastward towards the southern Balkans. Recent soundings show an EML in the warm sector airmass which leads to about 1 kJ/kg MLCAPE. Mid level cooling will reduce CIN but CAPE also decreases to the west. LCL heights should stay relatively low as surface dewpoints around 20°C are forecast over the Aegean Sea.
The kinematic environment should be much weaker than yesterday but 25 m/s deep layer shear and 15 m/s low level shear should be in place. Highest values of SRH1 and SRH3 (200 - 400 J/kg) are forecast for northern Greece and Albania. Remnants of present convective systems will probably reduce the potential for organized severe convection on Saturday but strong multicells as well as a few supercells will likely evolve, capable of producing severe / damaging gusts and / or an isolated tornado. Isolated large hail is not discounted either but severe gusts will be the main threat. A LVL2 is not warranted at the moment but if forcing is stronger and an organized convective line develops, an update will be issued.
...E Spain, Balearic Islands, W Mediterranean...
A well-defined cold front that stretches from the N Maghreb States towards central France will move northeastward. As the upper trough overspreads the western Mediterranean and parts of Spain, some hundred J/kg of CAPE will be created in an environment with 30 m/s deep layer shear and up to 20 m/s low level shear. Especially in the north of the Balearic Islands, southeasterly winds near the center of the surface depression will lead to SRH3 in order of 400 J/kg. Organized multicells and supercells will develop during the afternoon which will tend to cluster into one or two large MCSes. Those storms will likely be accompanied by isolated large hail, severe gusts and possibly an isolated tornado. The tornado / severe gust threat will decrease in the late evening but torrential rainfall may lead to flash floods, especially along the Spanish coast.
Low-end instability is forecast by GFS in an environment with very strong LL winds (30 m/s at 850hPa). Strong QG forcing will allow some organized multicells / linear systems that may produce severe / damaging gusts. Locally enhanced SRH1 may also allow an isolated tornado. A small LVL1 was issued for the region where instability and shear / SRH should be best.
Aviso do Estofex para hoje dia 3 de Novembro de 2008 na Europa.
Main feature this period remains the extensive quasi-stationary upper cyclone covering the SW portions of Europe, and maintaining an intense mid/upper level SWly flow over the western Mediterranean. E of this feature, tongue of warm/moist air is present over the central portions of the Mediterranean. At the surface, a weak low-pressure area will exist over the Biscay region while quiescent conditions prevail elsewhere over southern Europe. Multiple SFC low-pressure systems persist over the N Atlantic and extreme N Europe underneath an ample, meandering upper westerly jet stream.
... western Mediterranean regions ...
It seems that the best thermodynamic profiles will exist over the western Mediterranean, east of the low/mid-level thermal ridge spreading across Italy and the Adriatic Sea. Deep convection is expected over the western Mediterranean Sea, where DCVA-related ascent as well as frontogenetic forcing should act as main contributor in maintaining large/mesoscale ascent to sustain the convection. CAPE is anticipated to be rather weak, but DLS of 20 m/s should be present towards the central Mediterranean. Some threat exists for marginally severe hail/wind, though an isolated tornado or two cannot be discounted either, given that GFS advertises small patches of 10 m/s LLS across this region especially towards the end of the period.
Main issue will likely be the non-localized vertical-velocity distribution, which should result in rather widespread convection, which may also prove to be slightly elevated. Still, a marginal level-one threat appears to be warranted.
Towards the end of the period, a vort max should overspread the warm-sector air mass SW of Italy. This may result in better organized convection given stronger capping, and more focused low-level ascent ... along with anticipated strong shear and instability. This activity may well be associated with large hail and damaging wind gusts, and is thus included in a level-one area.
Chuvas torrenciais lançam caos nos centro de França
Os serviços meteorológicos franceses emitiram um alerta vermelho até à manhã desta segunda-feira para cinco departamentos que se encontram no curso do rio Loire. As autoridades temem o risco de inundações e apelam à populações para se deslocarem só em caso de necessidade.
Já na noite passada o departamento do Ródano foi atingido por chuvas intensas que provocaram grandes inundações. Várias estradas estiveram cortadas ao trânsito. A situação foi tão inesperada que não foi possível sequer accionar o sistema de alerta, como explicou o presidente da câmara de Rive-de-Gier. Nesta região mais de 300 pessoas foram obrigadas a abandonar residências e hotéis
As chuvas torrenciais que hoje têm estado a atingir as regiões de Bouches-du-Rhône e Lozère, deverão estender-se aos departamentos de Aveyron, Vaucluse e Puy-de-Dôme. Mais de 300 pessoas foram obrigadas a abandonar residências e hotéis.
Mantem-se até esta segunda-feira o alerta ao mau tempo em cinco departamentos franceses depois de um fim-de-semana carregado em ventos forte e muita chuva. A região de Haute- Loire foi ontem uma das mais atingidas por um tromba de água que causou inundações e muitos estragos.
Também na região Rhone Alpes a chuva forte deixou marcas. Várias centenas de pessoas tiveram de ser evacuadas. Carros destruidos, milhares de famílias privadas de electricidade durante várias horas, árvores caídas, estradas cortadas, um balanço de inúmeras horas de pesadelo para as populações das regiões atingidas pela catástrofe.
O mau tempo fez-se igualmente sentir em Espanha. Ventos na ordem dos 160 quilometros por horas atravessaram Terragona e Catalunha. Os bombeiros realizaram ontem mais de 500 intervenções. As águas terão sido responsaveis indirectas por uma explosão de gás em Almoster que causou dois feridos.
em outros pontos da Europa ,
se um lado tapa, do outro lado destapa.
Se a Ocidente , da Escócia à Ibéria já todos andamos agasalhados,
no centro e sudeste europeu o discurso do Aquecimento Global ainda faz sentido.
A temperatura máxima hoje no velho continente mostra essas anomalias
Os balcãs ,que por estas alturas são já bem agrestes,
continuam com tempo estável e uns invejáveis 22º,23º.
Para não falar em Moscovo que chega a Novembro sem ver neve.
Na Madeira (!!!!)e aqui no Continente já nevou.
Se de um lado tapa,
do outro destapa...
Aviso do Estofex para hoje dia 4 de Novembro na Europa.
A large upper low is situated over the Iberian Peninsula and western Mediterranean Sea and surface low moves from the Balearic Islands to southern France. Strong mid level height gradients create a strong steering flow from the south over the central Mediterranean and Italy, favorable for the development of severe storms in the very unstable airmass. GFS model forecasts a cold front at 700 hPa moving eastward from Sardegna, with associated zone of strong convergence and moisture near the surface.
The entire region of southern France, northern Italy and Slovenia should be aware of the threat of flash floods and land slides posed by forecast large precipitation sums by persisting storms and upslope moisture advection.
Strong mid and low level winds, backed near the surface, create an environment in which storms can easily become severe. Cagliari 00Z already shows such environment, with 900 J/kg CAPE and incredible shear. Ajaccio similar with less CAPE. Trapani 00Z throws also some low/upper level dry air in the mix for enhanced gusts.
GFS indicates deep layer shear (DLS) can reach 25 m/s in places, 0-3 km storm-relative helicity (SREH) ranges 150-300 m2/s2, supporting storm rotation, even soaring to values of 400-1000 m2/s2 over central and northeastern Italy during the late afternoon and evening. Combined with 10-15 m/s 0-1 km level shear vectors (LLS) in a large area, to possibly more than 20 m/s over central Italy, and low LCL heights, there is a significant potential for tornadoes, which may be violent. Large hail is possible as well, and during downbursts gusts of >20 m/s can occur, most likely in the level 2 areas.
Large SREH of 300-600 m2/s2 and significant LLS are calculated by GFS for the morning and afternoon through a convergence zone. This is supportive of supercells with large hail, gusts and an isolated tornado. Note that the current storm activity on the Mediterranean is complex, the GFS convective scheme reacts explosively (out of realistic bounds) and so the situation may have changed in the next model forecasts. Both the GFS and AFWA WRF precipitation look reliable so far and the shear and instability are supported by Nimes 00Z sounding.
Several waterspouts will likely occur throughout the western Mediterranean Sea.
E o Norte/Noroeste de Itália está sob alerta vermellho devido ás trovoadas e á percipitação
Aviso do Estofex para Hoje dia 6 de Novembro na Europa.
As the geopotential over northern Atlantic weakens, cut-off low over west Mediterranean starts to move north-eastwards. While quite cool air mass is present in the centre of this trough, warm air mass is advected northward over central and east Mediterranean into the Balkans. A ridge extends from east Mediterranean to eastern Europe and Scandinavia, while a cold arctic trough spreads into Russia.
Southern Italy, Adriatic
Latest satellite images indicate intense convection over southern Italy in the range of a strong low-level jet situated ahead of the cold front of the west-Mediterranean trough. During the forecast period, this system will slowly move eastwards, while the axis of a negatively tilted short-wave trough will enter central and southern Italy. Latest soundings from the low-level jet indicate winds in excess of 15 m/s at the 950 hPa level and quite moist low-level air mass, resulting in approximately 1000 J/kg CAPE at the northern nose (Zadar). Region of strongest instability will likely spread eastward into southern Adriatic and southern Italy later on, given rather high boundary-layer moisture and decreasing 850 and 700 hPa geopotential and temperature. On THU, latest GFS indicates intense lift ahead of the approaching trough axis, and thunderstorms will likely develop. Limiting factor is relatively weak convergence along the frontal boundary, and current thinking is that one or two multicells will likely grow into MCSs moving into southern Adriatic later on. Chance for severe convection is expected to be not very high as mid-level winds seem to be quite weak. However, strong low-level winds may produce some severe downburst wind gusts along the leading convective line. Additionally, slightly veering profiles especially near southern Italy seem to be favourable for tornadoes. Limiting factor is again weak low-level convergence. Large hail is not ruled out, while intense rain spreading into Balkans later on will pose a significant threat.
In the range of the trough centre of Atlantic low, models indicate cold mid-level air mass that will likely be unstable above the warm sea surface. Low-level convergence near the trough centre, quite moist low-level air mass and rather steep lapse rates are expected to be sufficient for deep convection. Severe wind gusts will likely be possible given strong synoptic winds.