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Air-mass trajectories and extreme episodes: Snowfalls on the natural region of the south-east coast of the Iberian Peninsula (1900–2005)
No full textThis paper analyses and characterizes snowfall events in one of the hottest,
most arid areas in continental Europe. Our information was taken from a snowfall
database that was partly our own, covering a period of over 100 years. The FLEXTRA
model of air-mass back-trajectories was applied together with our own subjective
synoptic classification. Data from the ECMWF Reanalysis of the 20th Century (ERA20C) were used for the calculation and clustering of the back-trajectories and the
establishment of synoptic weather types. The snowfall events were classified into 8
synoptic types and 4 first-level and 8 second-level back-trajectories. The meteorological
scenario for these extreme events was marked by mixed structures at altitude with a main
NE/SW axis and dipoles on the surface dominated by powerful North Atlantic anticyclones and back-trajectories from the NE at the three levels analysed (500, 1500 and
5000 m.a.s.l.)
Borrasca Konrad
No full textKonrad fue la decimoprimera borrasca de gran impacto de la temporada 2024-2025, nombrada por el IPMA (Instituto Portugués del Mar y de la Atmósfera) el 10 de marzo de 2025 a las 11 UTC. En el aviso de su nombramiento se informaba de que el centro de la borrasca se situaría a unos 200 km al norte de las islas Azores a las 15 UTC del martes 11 de marzo. Se esperaba que se produjera un aumento significativo de la intensidad del viento en todo el archipiélago, así como lluvias fuertes y temporal marítimo. En España, los efectos de Konrad tuvieron lugar durante el día 12, cuando una baja secundaria enlazada con el núcleo principal mediante un sistema frontal discurrió por el sur peninsular. Se registraron lluvias débiles a moderadas con tormentas locales y rachas muy fuertes en puntos del extremo sur
CYCLOPs: a Unified Framework for Surface Flux-Driven Cyclones Outside the Tropics
No full textCyclonic storms resembling tropical cyclones are sometimes observed well outside the tropics. These include medicanes, polar lows, subtropical cyclones, Kona storms, and possibly some cases of Australian East Coast Lows. Their structural similarity to tropical cyclones lies in their tight, nearly axisymmetric inner cores, eyes, and spiral bands. Previous studies of these phenomena suggest that they are partly and sometimes wholly driven by surface enthalpy fluxes, as with tropical cyclones. Here we show, through a series of case studies, that many of these non-tropical cyclones have morphologies and structures that resemble each other and also closely match those of tropical transitioning cyclones, with the important distinction that the potential intensity that supports them is not present in the pre-storm environment but rather is locally generated in the course of their development. We therefore propose to call these storms CYClones from Locally Originating Potential intensity (CYCLOPs). We emphasize that mature CYCLOPs are essentially the same as tropical cyclones but their development requires substantial modification of their thermodynamic environment on short time scales. Like their tropical cousins, the rapid development and strong winds of CYCLOPs pose a significant threat and forecast challenge for islands and coastal regions, and the effects of climate change on them should be considered.This work was made possible by Institut Pascal at Université Paris-Saclay with the support of the program TROPICANA, “Investissements d'avenir” ANR-11-IDEX-0003-01. Juan Jesus González-Alemán thanks support from AEMET and from the Spanish PID2023-146344OB-I00 project, funded by MICIU/AEI/10.13039/501100011033 y by FEDER, EU
Balance hídrico nacional. Número 26/2025
No full textBalance hídrico correspondiente al 20 de septiembre de 2025
