Analysis of a severe weather event over Mecca, Kingdom of Saudi Arabia, using observations and high-resolution modelling

Abstract

The dynamic and thermodynamic characteristics of a severe weather event that caused heavy wind and rainfall over Mecca, Kingdom of Saudi Arabia, on 11 September 2015 were investigated using available observations and the Weather Research and Forecasting model configured at 1 km resolution. Analysis of surface, upper air observations and model outputs reveals that the event was initiated by synoptic scale conditions that intensified by interaction with the local topography, triggering strong winds and high convective rainfall. The model predicted the observed characteristics of both rainfall and winds well, accurately predicting the maximum wind speed of 20–25 m s−1 that was sustained for about 2 h. A time series analysis of various atmospheric variables suggests a sudden fall in pressure, temperature and outgoing long wave radiation before the development of the storm, followed by a significant increase in wind speed, latent and moisture fluxes and change in wind direction during the mature stage of the storm. The model outputs suggest that the heavy rainfall was induced by a low‐level moisture supply from the Red Sea combined with orographic lifting. Latent heat release from microphysical processes increased the vertical velocities in the mid‐troposphere, further increasing the low‐level convergence that strengthened the event.

Diagnostic evaluation of extreme winter rainfall events over the Arabian Peninsula using high‐resolution weather research and forecasting simulations

“…Various parts of the globe are experiencing increased heavy rainfall events in terms of frequency and intensity due to climate change (Aggarwal et al, 2022;Boyaj et al, 2020;Goswami et al, 2006;Luong et al, 2017;Min et al, 2011;Nischal et al, 2022). The AP region has suffered from several devastating floods due to extreme rainfall events (EREs) in recent decades (e.g., Al-Khalaf & Basset, 2013;Dasari et al, 2017;Haggag & El-Badry, 2013;Kumar et al, 2015Kumar et al, , 2016Viswanadhapalli et al, 2016). The effects of these EREs have been under the radar of various sectors, from the government to the public.…”

Towards an End-to-End Analysis and Prediction System for Weather, Climate, and Marine Applications in the Red Sea

“…Using a convectivepermitting WRF configuration,Viswanadhapalli et al (2016) assessed the predictability of two extreme rainfall events formed over Jeddah while assimilating various combinations of conventional and satellite observations(Fig.11a). A similar WRF configuration was implemented byDasari et al (2017b) to study the Mecca 2016 extreme rainfall event. More recently, Luong et al (2020) investigated the impact of urbanization using WRF by incorporating an urban canopy model and urban land cover for several extreme weather events over Jeddah showing that urbanization enhanced rainfall by ~25%.…”

Retrospective Sub-Seasonal Forecasts of Extreme Precipitation Events In The Arabian Peninsula Using Convective-Permitting Modeling

“…These cross-Red Sea winds gather the moisture from the sea surface and transport it eastward (Hoteit et al 2021). The low-level moisture transport combined with orographic lift and diabatic heating over the mountain ranges in the southwestern AP increases the atmospheric instability, facilitating convective organization and extreme precipitation (de Vries et al 2016;Dasari et al 2017).…”

“…During this warm season from May to October, the precipitation at the southwestern tip of the AP is principally generated by southwesterly Indian monsoon winds and orographic lifting (Atlas 1984;Almazroui 2011;Viswanadhapalli et al 2016). The present study focuses on extreme precipitation events over the AP during the cool season, which are often associated with mesoscale convective systems (MCSs) (Dasari et al 2017;de Vries 2018). In general, MCSs occurring over land produce large areas of heavy precipitation (covering 100 km or more) and strong winds (e.g., Houze 1993; Schumacher and Rasmussen 2020).…”

“…CPMs have been widely applied in weather forecasting (e.g., Clark et al 2016) and climate projection (e.g., Prein et al 2015, Kendon et al 2017. Included in the CPM literature are some studies simulating extreme weather events over the AP (e.g., Deng et al 2015; Dasari et al 2017;Luong et al 2020b) and incorporation of data assimilation (Viswanadhapalli et al 2016) to improve short-range forecasts, which inform the methodological approaches in this work. With respect to convective precipitation, CPMs add substantial value in determining the amount, timing, and storm structure of convective precipitation (e.g., Prein et al 2015;Ban et al 2014;Kendon et al 2012).…”