FXUS66 KSGX 041801 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 1101 AM PDT Mon May 4 2026 .SYNOPSIS... A low pressure system off the central California coast will move slowly inland through central and southern California through Tuesday spreading cooling inland with high temperatures on Tuesday 10 to 15 degrees below average for inland areas and 15 to 20 degrees below average for the mountains. Southwest to west winds for the mountains and deserts will gust to 35 to 45 mph with isolated gusts to 60 mph. There is a also chance of showers through Tuesday. The greater chances for showers are for late this evening through Tuesday morning and across San Diego County from the coast to the mountains. It will be dry with a substantial warming trend for Wednesday through Monday of next week. High temperatures on Sunday will be 10 to 15 degrees above average for inland areas to as much as 15 to 20 degrees above average for the inland valleys and lower coastal slopes of the mountains. There could be extreme heat in the lower deserts as early as Saturday and continuing through at least Monday of next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... New Aviation and Marine Discussion... .SHORT TERM (Today through Wednesday)... A low pressure system off the central California coast will move slowly inland through central and southern California through Tuesday spreading cooling inland with high temperatures on Tuesday 10 to 15 degrees below average for inland areas and 15 to 20 degrees below average for the mountains. Southwest to west winds for the mountains and deserts will gust to 35 to 45 mph with isolated gusts to 60 mph. There is a slight chance of showers through today from the coast to the mountains. The greater chances for showers are for late this evening through Tuesday morning and across San Diego County from the coast to the mountains. Through Tuesday, rainfall across Orange, southwestern San Bernardino, and western Riverside Counties, rainfall could range from less than one-tenth inch near the coast to one-tenth to locally one-quarter inch in the mountains. For San Diego County, rainfall could range from one- tenth inch near the coast to one-tenth to locally one-third inch in the mountains. Wednesday will be dry with a substantial warming trend through early next week. High temperatures on Wednesday will warm as much as 12 to 18 degree for the mountains and high desert, but with high temperatures still a few degrees below average for most areas. High temperatures on Wednesday will range from the mid to upper 60s near the coast to the 70s for the Inland Empire with the lower deserts in the upper 80s to around 90. && .LONG TERM (Thursday through Sunday)... Substantial warming will continue on Thursday with the warming slowing for Friday through Monday. With the warming, high temperatures for Monday of next week will be as much as 15 to 20 degrees above average for some inland areas. High temperatures for next Monday will range from the 70s near the coast to the 90s to around 100 for the Inland Empire with 105 to 110 for the lower deserts. The Heat Risk based on the NBM forecast would be sufficient for an Extreme Heat Warning for the lower deserts beginning on Saturday and continuing through at least Monday of next week. The Heat Risk for the inland valleys could be sufficient for a Heat Advisory beginning on Monday. && .AVIATION... 041800Z....Coast/Valleys...Low clouds based between 3000-6000ft MSL will continue through the late afternoon/evening. Could see the occasional cigs 2000-2500ft MSL in DZ or -SHRA, with chances increasing after 04-06Z Tuesday. .Mountains/Deserts...Strong westerly gusts up to 25-35 kts with isolated gusts of 45 kts are expected after 19-21z. This will create moderate to strong up/down drafts and local LLWS in the lee of mountains. Expect reduced vis in BLDU in deserts areas. Coast-facing mountain slopes will occasionally be obscured between 3000-6000 feet MSL in BR where clouds intersect terrain. Chances will increase after 02-04Z Tuesday. && .MARINE... No hazardous marine conditions are expected through Friday. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory until 9 PM PDT this evening for Apple and Lucerne Valleys-San Gorgonio Pass near Banning. PZ...None. && $$ PUBLIC...Martin AVIATION/MARINE...Villafane