By Reginald Stanley. Posted July 25, 2014, 10:12 PM.

Thursday brought widespread triple-digit heat to the region, prompting the National Weather Service to issue heat advisories in several counties. Thundershowers were also reported in parts of San Diego County early Friday morning.

Temperatures were hottest in Lake Elsinore and Menifee, where both WeatherCurrents stations recorded highs of 112 degrees. Wildomar was not far behind with a high of 110 degrees. Only four of the nineteen active WeatherCurrents stations did not reach or exceed 100. San Diego's City Heights neighborhood was the coolest with a high of 89 degrees on Thursday.

The heat arrived after an unusually mild stretch of days, featuring temperatures not normally seen in July. This was accompanied by the morning marine layer, also uncommon for July. Monsoonal moisture to the east was not expected to drift west of the mountains, however they did Friday morning. A brief spell of rain and thunder was reported in Santee. No WeatherCurrents stations recorded any rainfall.