Summer precipitation over most of the tropical Americas exhibits maxima in June and September, and a relative minimum in July. The minimum in summer precipitation over the northeastern (NE) tropical Pacific is known as the midsummer drought (MSD). Several theories have been put forward to explain the origin of the MSD, but most of them fail at addressing simultaneously the various elements that characterize it. The temporal evolution of summer precipitation over the NE tropical Pacific warm pool and over the Intra-Americas Seas (IAS) is related, but not the result of the same process. Over the NE Pacific warm pool, the temporal evolution of convective activity is closely related to sea surface temperature (SST) variations, whereas over the IAS, the Caribbean low-level jet (CLLJ) with maximum intensity in July appears to be the key factor. The CLLJ produces ‘gap flow’ over Central America that reaches the NE tropical Pacific and stronger easterly winds. This low-level flow leads to a decrease in SSTs and a westward shift of low-level moisture convergence that combined with subsidence result in the MSD. At the CLLJ exit region, intense tropical convection enhances during July reducing the chances that large-scale circulations, such as the North Atlantic Subtropical High (NASH) inhibit precipitation over the entire tropical Americas. The strong ascending motion off the Caribbean coast of Nicaragua and Costa Rica contributes to enhanced subsidence in the surrounding regions and to the MSD. As the CLLJ and tropical convection in the western Caribbean weaken during August and September, tropical convection increases once more over most of the tropical Americas and produces the second maximum in precipitation that completes the two peaks distribution of summer precipitation. Therefore, the fluctuations in the intensity of the CLLJ appear to be a key dynamical element to explain the MSD.

In athletics, achieving peak performance during competitions is crucial. Warm-up strategies play a crucial role in optimizing the strength-speed performance of sprinters in athletics, especially tailored to the physiological demands of speed events. The need to balance flexibility, prevent injuries, and enhance power output makes the selection of an effective warm-up protocol essential. This narrative review examines different warm-up methods used by athletes and their effects on strength-speed in sprinters in athletics. The main findings indicate that Foam Rolling (FR), Isometric Exercises and Pre-Competitive Massages have no significant effects on sprint performance. Static stretching and prolonged Pre-Competitive Massages have negative impacts on strength and power. The Vibration Platform enhances step length, step rate and running velocity, jump height and total number of jumps performed in a 30-s period in non-experienced sprinters. Eccentric Exercise increases vertical force, Post-Activation Potentiation (PAP) demonstrates a reduction in 100-meter time and short-term improvement in vertical and horizontal jumps. Blood Flow Restriction (BFR) significantly improving jump height and flight time. Various warm-up methods have been identified, some focusing on flexibility, others potentially detrimental, and some enhancing strength and power. Implementing effective warm-ups, particularly those promoting strength and power, poses a challenge for coaches seeking reliable alternatives to boost performance.

The Monterrey Metropolitan Area (MMA) is located in northeastern Mexico in a semi-arid region. As in other areas of the world, prolonged and severe meteorological droughts are recurrent. Meteorological droughts affect the level of dam reservoirs, rivers, and groundwater (aquifers) in the region to the extent they become hydrological droughts which in turn may contribute to socioeconomic droughts. The recent dry event (2011–2013) in northern Mexico severely affected various socioeconomic sectors and may serve as an example of future climatic and hydrologic conditions in this region. Meteorological droughts in northeastern Mexico, mostly induced by anomalously intense subsidence, frequently result in hydrological droughts and intense pressure in the water resources services of the Monterrey Metropolitan Area (MMA), one of the largest cities in Mexico. Landfalling tropical cyclones entering northeastern Mexico historically have alleviated water crises during prolonged droughts. In 2013, the rains from tropical cyclone Ingrid helped to recover water levels in the system of dam reservoirs that provides water to the MMA. However, water management is only one part of a complex socioeconomic system that must respond to the growing demands for water in a region where aquifers are already overexploited. Trends in the atmospheric circulation indicate that droughts in the region may become more severe in the coming decades. Improved water management programs and protocols should be considered in addition to closer reviews of the hydraulic infrastructure. Water transfers from one region to another should be carefully planned because solving a problem in one place may adversely affect another. The use of climate information may be critical to avoidance of water conflicts in the future.

Introduction: Easterly waves (EWs) are a dominant atmospheric phenomenon in the tropics. EWs in Mexico, Central America and the Caribbean region produce intense precipitation and significantly contribute to the summer rainy season, but some climatologies indicate their activity is weak or even null over the Intra-Americas Seas (IAS). As it is shown in the present study, EW activity over the IAS is not negligible but its variability is less than that off the western coast of Africa.Method: Given the well-known coupling of wind and atmospheric moisture in EWs, their characteristics may be described using vertically integrated moisture fluxes (VIMF) and their divergence. By means of Hovmöller diagrams, lagged correlations and composite analyses, the propagation and the meteorological effects of these waves across the Caribbean Sea and the Gulf of Mexico, particularly on moisture and rains, are examined.Results: It is observed that as EWs propagate, the VIMF convergence increases the level of precipitable water which frequently results in intense precipitation events. High frequency variability of the meridional component of the VIMF is used to estimate EW activity. Over the Caribbean Sea, EWs are less energetic than in the eastern tropical Atlantic even while the number of waves over these regions is comparable.Discussion: When the Caribbean Low-Level Jet (CLLJ) is strong, EW activity tends to diminish due to a decrease in precipitable water (PW), sea surface temperature (SST) over the Caribbean, and possibly to an intensified vertical wind shear. Therefore, years of a stronger than normal CLLJ tend to result in summer precipitation below normal over most of the IAS and southern Mexico.

Se analizó la dinámica de las inundaciones más importantes ocurridas en Tulancingo, Hidalgo, centrándose en la caracterización de la amenaza de eventos de precipitación extrema. El estudio de la climatología de la precipitación permitió determinar patrones temporales y espaciales, así como las fechas de los eventos extremos. Con base a una investigación hemerográfica se relacionaron los casos de eventos extremos con desastres (inundaciones) registrados. Los patrones espaciales asociados a los desastres registrados permiten establecer estrategias de prevención basadas en el pronóstico de precipitación.

Se comparan las métricas de 37 modelos climáticos globales (GCMs, por sus siglas en inglés) de la Fase 6 del Proyecto de Intercomparación de Modelos Acoplados (CMIP6) con el objetivo de simular el clima de Guatemala del periodo de 1971 al 2014. La temperatura y precipitación mensual fue comparada con los datos de observación de la Unidad De Investigación Climática de la Universidad del este de Anglia (CRU). Se generó un ranquin de modelos basado en la menor distancia entre tres dimisiones basado en tres métricas; Coeficiente de Correlación de Pearson (CCP), Error medio cuadrático (RMSE) y Desviación estándar (DS). Este ordenamiento coincide con los mejores valores de eficiencia Nash-Sutcliffe (NSE) para temperatura y eficiencia Kling-Gupta (KGE) para la precipitación, demás se calculan las métricas; coeficiente de correlación de Spearman (CCS), errores de sesgo medio (MBE) y el absoluto medio (MAE). Para precipitación los primeros 5 modelos presentan valores KGE de entre 0.5 y 0.7, el CCP y CCS entre 0.7 a 0.8 comparados con CRU. Para temperatura los primeros 5 modelos presenta valores de NSE de entre 0.5 a 0.6, CCP y CCS de 0.8. Los modelos sobreestiman levemente la temperatura y subestiman la precipitación. Los modelos con mejor habilidad fueron CIESM para temperatura y el modelo IPSL-CM6A-LR para precipitación. Adicionalmente se compara el promedio de 66 estaciones locales con CRU, presentando un KGE 0.51, CCP 0.77 para precipitación y NSE -0.17 y un CCP 0.20 para temperatura. Finalmente, se presenta una tabla con los 10 primeros modelos para cada variable.