San Diegans should brace themselves for a rise in temperatures this weekend, with a Heat Risk alert issued by the National Weather Service (NWS). According to the National Weather Service forecast, temperatures are set to soar above the seasonal average, with the mercury hitting highs around 115 degrees in the lower deserts and around 100 degrees in the far inland valleys come Sunday.

The National Weather Service discussion detailed a "drier and slightly cooler" Friday night, with a heat build-up expected on Saturday and Sunday. However, this welcome cooler night won't last long as the valley areas are preparing for the greater warming in temperatures over the weekend.

Furthermore, the region saw a record level of precipitable water this June in San Diego, which measured 1.78 inches earlier Wednesday. Yet, as the southwest flow aloft progresses, a drying pattern will be evident into early Saturday, with values declining significantly.

In coastal areas, too, residents are witnessing an atmospheric shuffle; low clouds have stretched to cover parts of the coast and are predicted to linger into Friday morning. In the mountains and deserts, strong west winds are on the forecast with gusts potentially reaching up to 45 mph through the San Gorgonio Pass, possibly leading to "Mod up/downdrafts over and east of the mountains", as stated by the National Weather Service in their Area Forecast Discussion.

With an Excessive Heat Warning in place until 8 PM PDT this evening for certain areas, including the Coachella Valley, San Diego County Deserts, and San Gorgonio Pass near Banning, residents are urged to take precautions against the sweltering heat. The marine conditions, on the other hand, are expected to remain non-threatening through Monday.