San Diegans can expect cooler temperatures and light showers as a low pressure system moves through the region starting late Sunday. According to the National Weather Service (NWS) San Diego, today's highs will be 3-5 degrees lower than Saturday, with little change in low desert areas. However, a significant temperature drop is forecast for Monday, with highs 10 to as much as 25 degrees below normal.
Not only will temperatures take a nosedive, but light rainfall is anticipated late Sunday through Monday night, especially on the south facing slopes of the San Bernardino Mountains. "Mostly light rainfall is expected late tonight through Monday night, with the highest accumulations on the south facing slopes of the San Bernardino Mountains", NWS San Diego reported. Coupling with the rain, gusty winds are predicted through mountain passes and deserts, including local gusts over 50 mph. This may lead to reduced visibility due to blowing dust in desert regions.
The marine layer also makes its presence felt, spreading into the foothills this morning and creeping through locations like the Cajon Pass. Higher elevations above the marine layer will enjoy mostly clear skies while areas west of the mountains brace for light showers. As the Area Forecast Discussion reported, "Patchy drizzle is possible this morning, mainly across the valleys where the cloud deck appears to be thicker." Clouds are expected to retreat towards the coast by early afternoon.
For outdoor enthusiasts and commuters, it's important to note that Monday will bring stronger winds in the afternoon and evening — strongest below the San Gorgonio Pass and along I-8 near the Imperial County border. The NWS advises, "The Wind Advisory may need to be expanded later today to cover the San Gorgonio Pass and San Diego County Deserts for Monday afternoon into Monday night." The high desert remains under a Wind Advisory from this evening through Monday night.
As for the marine forecast, light precipitation is expected Sunday night through Monday morning, with amounts generally under 0.10 inches. Meanwhile, fire weather conditions will see relative humidity drop to 15-25% with stronger winds this afternoon through mountain passes, increasing the challenge for firefighting efforts in some regions. The marine layer could bring improved humidity and a chance of showers tonight into Monday evening, potentially aiding in fire containment efforts.
A brief warming trend will occur on Tuesday, followed by another potential temperature dip and more light precipitation due to another low pressure system expected by Thursday. Temperatures are set to rise again as we head into the weekend, with ridging bringing warmer weather to the area.
