textproduct: San Diego

SYNOPSIS

Low pressure systems will impact the region through Monday. These are going to be accompanied by cooler, wetter. amd windier weather. A chance for light showers will occur tonight into Saturday morning. These weather systems will also bring the chance of light to moderate rainfall and high elevation snow. The heaviest rainfall and mountain snowfall is expected on Sunday, where there is a slight chance of thunderstorms west of the mountains. This low pressure system may linger over the area into Monday, bringing additional light showers. Drier and slightly warmer weather is expected by the middle and end of next week.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...

Fair weather cumulus clouds are beginning to form this afternoon out ahead of an area of low pressure sits just west of the Monterey Bay. Winds as of noon are currently gusting near 25-40 MPH across some mountain areas. These winds will spread more into the deserts later this afternoon and evening. As the weather system moves inland over Northern California later today into Saturday morning, a weak frontal passage will move over our region. This will bring the chance for light showers along and west of the mountains overnight into Saturday morning. Amounts will be light with some areas receiving up to one tenth of an inch, others nothing. Coastal slopes of the mountains may see locally over one quarter of an inch of rainfall. As the low passes, this will bring in cooler air across the region by Saturday with highs near 70 west of the mountains and high desert with highs staying in the 80s across the low deserts. Saturday afternoon and evening look to be mainly dry with partly to mostly clear skies.

A stronger area of low pressure is beginning to exit the Gulf of Alaska and push closer to the West Coast today. This system will continue to drop southward, impacting the area. The low will bring continued windy conditions across the mountains and deserts this weekend with highest winds expected on Sunday with the passage of the system's cold front. Sunday will also be the windiest day at the immediate coast with around a 20-30% chance of seeing wind gusts over 25 MPH in the morning and afternoon. Models indicate the weather system taking a similar path to the low pressure system of today, focused on Northern California. This system will be larger however, where a more defined cold front is expected to move through Southern California. High resolution models begin light showers out ahead of the front a bit before midnight Sunday, becoming more widespread in nature Sunday morning. The main front looks to pass through from north to south Sunday morning into the afternoon hours. Snow levels will fall as low as 5,000 feet on Sunday night. Total snowfall accumulations will be close to one to two inches for areas above 6,000 feet. This system may bring a slight chance of thunderstorms with it as well, where rain rates may near one half inch per hour in any storm. This will also bring the coldest air of the week to the region with high temperatures 5 to 15 degrees below normal; say hello to the 70s in the lower deserts and only reaching into the 40s and 50s across the mountains.

Model guidance continues to slow the weather system down on Sunday evening into Monday. This would bring the chance for continued shower activity across the area, with drying occurring from north to south late Sunday night through Monday morning. Another area of low pressure moves in from the Gulf of Alaska into the Northern Rockies by the middle and end of next week. This will create a broad troughing pattern over our region, leading to dry conditions and temperatures closer to average.

Mountains/Deserts

West to southwest winds increase after 20z this afternoon with gusts 35-50 kt through passes, along deserts slopes and locally into the deserts. Local areas BLDU (vis 3-5SM) expected. Moderate up/downdrafts in lee of mtns. Wind gusts relax by 06-09z Saturday, but are expected to pick back up again after 20z Saturday afternoon.

MARINE

There is a slight chance of thunderstorms Sunday afternoon. Additionally there will be periods of increased northwest winds with gusts 15 to 20 kt and choppy seas that could generate hazardous conditions through the day Sunday.

SKYWARN

Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions.

SGX WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...None.