Roberto Granda

#HeadsUp 🌡️➡️⛈️ Despite the strong heatwave signal currently projected by operational models over parts of central and western Europe, the broader synoptic pattern may become increasingly unstable later in May, with potentially rapid adjustments in upcoming model runs. The current ridge over western Europe ( Barents Sea ) , counteracted by lower geopotential heights near the North Caspian and Ural sector, may eventually favor Rossby-wave amplification and trough detachment toward southwestern Europe and the western Mediterranean — as illustrated by the black arrow. Colder, denser air masses can undercut and displace warm ridging patterns across western Europe, especially under amplified spring flow regimes. This might happen at the same time with formation of Cyprus Low in East Mediterranean sea ( which had materialized yet) . This setup resembles a classical positive North Sea–Caspian dipole (+NCP)-type configuration, a transitional-season pattern that tends to recur more frequently during spring and autumn. If this evolution verifies, cut-off low / #DANA development near Iberia or the Balearic region cannot be ruled out, increasing the likelihood of storminess across inland and northeastern Spain during the final decade of May. The attached 20-analog spring composite also supports the possibility of a colder upper trough/basin forming over the western Mediterranean. At this stage, GFS and ECMWF do not fully support this scenario yet, but the currently projected persistent heat dome may become less stable in subsequent runs. In simpler terms: I broadly agree with Javier ( @Canalcienciaym ) that a transient Rossby-wave amplification during spring should not automatically be interpreted as a long-duration or extreme heatwave regime. Heat waves occur when latent heat builds up over several days while exceeding the high percentile of the period expected temperatures , holding heat into concrete building that radiates heat back at us day and night and persistently for extended period exceeding 4 consecutive days , this pattern is however dynamic and Fastly changing. Indeed the digital models supports this possible scenario at the meantime, a Cyprus Low is expected and it had formed but no Balearic sea Low had formed yet, next few days runs in those models can be very important.

A partir del miércoles entraremos en un episodio de #temperaturas altas para la época del año. El pico llegará, previsiblemente, el viernes, con máximas #caniculares en los principales valles del interior👇