Alerta de tormentas y fenómenos severos

Tarde entretenida para Cataluña y Aragón:





 

Estofex pone un nivel 1 apuradillo para Portugal y Extremadura y zonas limítrofes.



DISCUSSION

... Portugal and Spain ...

At 16 Z (31st March) the surface 10°C isodrosotherm moved well ashore and this onshore flow continues during the night before moist inflow relaxes as cyclonic vortex moves more to the east. Confidence is high that best BL moisture will be found from the Serra da Estrela (Portugal) to Sierra de Gredos and all the way to the Sierra Nevada (Spain) with dewpoints in the lower tens. Forecast soundings show drier air atop that moist surface layer, so daytime mixing may bring dewpoints down a few degrees. Further east, moisture becomes worse with highest values confined to the mountainous areas.

With 500 hPa temperature dropping to less than -20 °C, lapse rates become steep enough for modest MLCAPE build-up, probably maximized over Portugal and W-CNTRL Spain. CAPE peaks at 500-800 J/kg with a rapid decrease to the east. In the LL CAPE field, signals of abundant CAPE appear with weak moisture pooling along the upslope side of the complex topography...up to 150 J/kg LL CAPE is forecast.

Shear will be very weak, so pulsating storms with a gradual tendency for messy clustering are expected. Locally stronger updrafts and a combination of a lowered WBZ and a dry subcloud layer all assist in the chance of an isolated large hail event and strong wind gusts. Given aforementioned CAPE distribution, an isolated funnel/short-lived tornado event can't be excluded due to a messy dispersal of various storm induced outflow boundaries, which locally increase shear on the meso-gamma scale. The thunderstorm activity slowly decreases after sunset as the BL cools down, but the activity may last well into the night with cold-core vortex atop rough topography.

De todos modos, los mapas convectivos del GFS y de HIRLAM difieren sensiblemente, siendo más favorables los de esta última, con el MLCAPE metido más dentro en la península, LLCAPE también un poco más al interior y cizalladura ligeramente más elevada. También ven ambos una ligera helicidad, ligeramente mayor en el modelo europeo, con lo que quizás pueda haber alguna sorpresilla...o son las ganas que ya tengo 

Estofex pone un nivel 1 apuradillo para Portugal y Extremadura y zonas limítrofes.



DISCUSSION

... Portugal and Spain ...

At 16 Z (31st March) the surface 10°C isodrosotherm moved well ashore and this onshore flow continues during the night before moist inflow relaxes as cyclonic vortex moves more to the east. Confidence is high that best BL moisture will be found from the Serra da Estrela (Portugal) to Sierra de Gredos and all the way to the Sierra Nevada (Spain) with dewpoints in the lower tens. Forecast soundings show drier air atop that moist surface layer, so daytime mixing may bring dewpoints down a few degrees. Further east, moisture becomes worse with highest values confined to the mountainous areas.

With 500 hPa temperature dropping to less than -20 °C, lapse rates become steep enough for modest MLCAPE build-up, probably maximized over Portugal and W-CNTRL Spain. CAPE peaks at 500-800 J/kg with a rapid decrease to the east. In the LL CAPE field, signals of abundant CAPE appear with weak moisture pooling along the upslope side of the complex topography...up to 150 J/kg LL CAPE is forecast.

Shear will be very weak, so pulsating storms with a gradual tendency for messy clustering are expected. Locally stronger updrafts and a combination of a lowered WBZ and a dry subcloud layer all assist in the chance of an isolated large hail event and strong wind gusts. Given aforementioned CAPE distribution, an isolated funnel/short-lived tornado event can't be excluded due to a messy dispersal of various storm induced outflow boundaries, which locally increase shear on the meso-gamma scale. The thunderstorm activity slowly decreases after sunset as the BL cools down, but the activity may last well into the night with cold-core vortex atop rough topography.

De todos modos, los mapas convectivos del GFS y de HIRLAM difieren sensiblemente, siendo más favorables los de esta última, con el MLCAPE metido más dentro en la península, LLCAPE también un poco más al interior y cizalladura ligeramente más elevada. También ven ambos una ligera helicidad, ligeramente mayor en el modelo europeo, con lo que quizás pueda haber alguna sorpresilla...o son las ganas que ya tengo 

En el sur de Galicia ya se comienzan a desarrollar núcleos desde hace poco y tiene pinta de extenderse a Pontevedra con facilidad por desplazamiento E-W y desarrollo.

  Desde las tres de la tarde una tormenta sobre Belvis de la Jara, oeste de la provincia de Toledo todo el cielo completamente nublado, ha llovido un poquitin y ahora ya esta saliendo el sol.
No descarto otro proximo episodio de tormenta por la zona.

Menudas tormentas, aver lo que pasa!

Para hoy tenemos una situación bastane similar a la de ayer:



DISCUSSION

...Portugal and Spain ...

No major changes compared to yesterday's outlook. The main difference will be better moisture now also evident over E-Spain with lowest values (in the lower single digits) along the S/E Meseta Central. Surface dewpoints elsewhere in the lower tens counteract marginal weaker mid-level lapse rates, so roughly 500 J/kg MLCAPE are expected within the level 1 and lower values to the east.

Shear remains weak, so again pulsating thunderstorm activity is anticipated with rapid and messy clustering forecast. Isolated large hail and gusty winds will be the main hazard. LL CAPE magnitude decreases somewhat compared to yesterday but low LCLs and locally enhanced shear along various outflow boundaries may assist in an isolated funnel/short-lived tornado event. The activity graduall decreases after sunset as the boundary layer cools down.

Despite marginal environment, we again went ahead and issued a low-end level 1 as yesterday's convection featured numerous short-lived but intense thunderstorm cores, enough for hail production.

A few thunderstorms may form as far to the NE as S-CNTRL France, as a warm front and attendant moist warm sector expand northeastwards. Surface dewpoints along the coasts of S/SW-France already approach 10°C (as of 20Z on the 1st), so with 500 hPa temperatures around -20°C enough CAPE build-up for a sporadic and short-lived non-severe thunderstorm event may materialize. The activity rapidly decays after sunset.

La tarde promete:

A level 1 was issued for north-eastern Spain and west Mediterranean mainly for large hail.

In the wake of the European trough, a strong north-westerly jet extends across south-western Europe. Jet streaks embedded in the flow will cause QG forcing. Although the lapse rates and low-level moisture are rather poor, diurnal heating will likely be strong enough to build some weak CAPE as expected by latest GFS. Some showers and thunderstorms may develop. Given the strong deep layer vertical wind shear, large hail is not ruled out with these storms. The storms will likely weaken from the west given decreasing moisture.

 

  Tengo el 1 casi encima 

Me da que ha sido una rallada de Estofex, ya que el GFS no pone nada destacado y el Inm (hirlam) tampoco...

En el sat24 se ve ahora mismo algo sospechoso en el norte de Girona y frontera francesa, moviéndose anomalamente hacia el sureste. 

Me da que ha sido una rallada de Estofex, ya que el GFS no pone nada destacado y el Inm (hirlam) tampoco...

Estofex NO ha fallado

 

ESTOFEX para hoy:



De momento -mapa de rayos en mano- parece que se está cumpliendo..