Por cierto, jota... es la primera vez que veo una discusion tan larga en ESTOFEX...
A ver si algun alma caritativa se atreve con ella, por que al ser tan complicada yo mepierdo...
....Strait of Gibraltar, SE / E Spain and the Balearic Islands ...
Latest loop of WV images and sounding ascents ( yesterday, 12Z ) provide enough confidence that global models like GFS handle current strength and placement of weakly positive tilted upper-level trough over Spain / Portugal. Intense 110kt streak curving southwestward on its upstream side ( refer to Brest 12Z ), supporting a constantly SW - NE elongation of this upper-level feature with no notable movement. Degree of amplification and strength of developing LL depression over Morocco are the main uncertainty regarding coverage of expected thunderstorms.
Cold front ( penetrating well inland during the past 36 hours and being placed along the Atlas mountains ) will transform into a warm front during the next 24 hours as pressure gradually falls over Morocco and WAA picks up during the afternoon and evening hours over NW Algeria. This frontal boundary is forecast to reach a line NE Morocco - Balearic Islands during the evening hours and will be the focus for the strongest thunderstorm threat.
Areas east of this front will be mostly capped as 850hPa temperatures soar at or above 20°C.
Numerous short waves, ejecting out of the base of the upper-level trough will likely enhance the lift over SE / E Spain and the Balearic Islands although the strongest one is forecast to cross the area from the SW druing the evening and night hours. Although GFS tries to develop a coupled upper-level jet structure ( also indicative as models boost divergence values ) the spread in the model pool is still too large to buy one solution.
Latest thoughts are that numerous thunderstorms develop in the level-1 area during the forecast period, which could easily accrete in small clusters of rapidly forward propagating lines of storms.
During the evening and night hours, scattered to widespread storms should evolve mainly west / southwest of the Balearic Island and eastern Spain, moving rapidly towards the NE. NOGAPS and GEM indicate a possible cluster of storms during the latter part of the forecast period just west / northwest of the Balearic Islands with an attendant severe weather threat.
During the whole forecast period, parameters for rapid storm organisation are fine as DLS increases to 30m/s and lower wind field responses to the evolving LL depression over Morocco with backing and hence a broad area of intense LL shear. SSTs of about 25°C and a humid PBL all indicate the chance that storms over the Mediterranean will be surface based and parcels of the highly helical environment ( ~ 400 J/kg SRH3 and 150-300 J/kg SRH1 ) could easily be incorporated. Mid-level lapse rates will steepen during the period and weakly capped ICAPE values of above 2000 J/m°2 should be realized. The main risk will be a severe to possible damaging wind gust threat, especially if storms line up ( with embedded bowing line segments or supercells ). The tornado threat is also enhanced with mesoscale features like outflow boundaries playing an important role.
The hail threat should increase over eastern / southeastern Spain, as instability rapidly ease further inland and storms tend to be more elevated in nature. Shear and helicity are still impressive and an isolated large hail report will be likely.
A broad 1 was issued because there are still too many uncertainties left. Higher probabilities will be issued if model trends finally point to an area of significantly enhanced severe weather.
The same set-up, but somewhat weaker shear will be present over the Strait of Gibraltar and a few severe thunderstorms with an attendant severe wind gust risk can be expected.
Tema: Seguimiento ESPECIAL: episodio de tormentas sobre la Ibérica (22-08 al 26-08) (Leído 17557 veces)