Ojo con el dia de hoy...
Aviso importante de Estofex, y estos no suelen fallar mucho... meto la prevision en ingles a ver si algun iluminado puede traducirnos el texto...
SYNOPSISThree low pressure systems are present on the European map today. One low over Scandinavia with a trough and cold front affecting northern parts of Western/Central Europe, one low over the Iberian Peninsula and one low over the southern Balkan/western Turkey region. Between these lows, a large unstable saddle area with weak flow through a deep layer and only local forcing is present, allowing for mostly isolated thunderstorms.
These could become more organised along the northern parts of the central European thunder area as the cold front (with steep moisture gradient) comes in from the WNW. Compared to yesterday, a larger area is forecast by GFS to be uncapped and this seems well confirmed by the 00Z Tuesday soundings compared to 12Z Monday with colder mid levels and moister boundary layers.
Shear is insignificant though, evidenced by 00Z German soundings, so despite rather unstable profiles with steep lapse rates over the 900-600 hPa layer, hailstorms should be rare due to poor updraft/downdraft organisation in most cells. An isolated severe gust and flash flood seems possible.
Note that GFS 0-1 km average mixing ratio predictions seem in general 1-2 g/kg too low the past days.... leading to too conservative model MLCAPE estimates... and CIN should be less as well.
DISCUSSION...Spain and Portugal...Both instability and deep layer shear are forecast to increase compared to previous days, shear from moderate to high values (15-25 m/s 0-6 km and 1-8 km) and also low level shear from weak to moderate (8 m/s) to strong in the evening over the western parts (GFS18Z forecast >10 or 12 m/s). SREH3 is progged to reach over 250 m2/s2 over southeastern Spain during the afternoon. Abundant deep convergence should be present, but mid level QG support will switch from positive to slightly negative during the late afternoon... this may prevent to some extent development of a large MCS... but not too sure about that.
Main convective mode seems long-lived multicell and especially supercell storms with a chance of large hail, and some severe gusts. Chances for a tornado are more enhanced in/towards Portugal where low level shear would be better, though not fenomenal.
One or a few MCSes are possible during the evening, posing a main threat of severe gusts.
Voy a intentarlo yo por encimilla, por que un aviso de estos no se ve casi nunca...
asi a simple vista leo que la inestabilidad sera mas acusada que en dias previos, y que los valores de cizalladura seran bastante mas altos en niveles altos y algo mas altos en niveles bajos, aunque por la tarde seran mas altos en la parte occidental de la peninsula...
El valor de SREH3 (y no hablo de SRHEK
, a ver si isotacas nos ilustra) alcanzara valores de 250 m2/s2 en el sureste peninsular esta tarde... habra convergencia profunda pero (esto ni idea de lo que es) algo en el nivel QG al final de la tarde impedira hasta cierto punto la formacion de un gran Sistema Convectivo de Mesoescala, aunque esto no es demasiado seguro...
la conveccion puede dar lugar a multicelulas y especialmente a supercelulas con granizo grande y viento severo, siendo Portugal donde es mas probable la aparicion de tornados debido a los valores de cizalladura en niveles bajos, aunque no sera este valor el ideal... son posibles uno o mas Sistemas Convectivos de Mesoescala...