An approaching low pressure system from the west will bring occasional mostly light showers today. Rain will become heavy at times late tonight into Saturday along with a chance of thunderstorms, then gradually decreasing showers for Saturday night and Sunday. There will be another round of showers around Monday into Tuesday and possibly again around Thursday or Friday.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
.Morning Update,
Radar imagery shows light showers continuing to move in from southwest this morning as a shield of clouds is seen across the region on satellite. Some spots in our area have received over one quarter of an inch since last night. Hi-res models continue to show intermittent light to locally moderate showers. Model guidance is in better agreement on the onset timing of the heavier and more persistent rain activity starting sometime around 9 PM tonight. This wave of moisture will move in from south to north, bringing moderate to locally heavier rain and isolated thunderstorms through the night into the first half of Saturday afternoon. Bands/ribbons of heavier precipitation will occur on Saturday morning into the early afternoon, but there is lower confidence in exactly where these set up. Whoever finds themselves under these bands of precipitation, will see heavy rainfall in a short amount of time. This time period will be associated with the highest risk of flooding over our area. We continue to communicate that this flood threat will be across all areas, including the deserts! As we always preface, please do not drive through flooded roads and remember to "Turn Around, Don't Drown!"
As we meteorologists like to say, "the storm door has been propped open." Forecast models and confidence is increasing that another weather system will move through the area by Monday and Tuesday, as well as an additional system that may approach our region by later next week. Stay tuned and prepared by keeping updated on the forecast and following local police, fire, and emergency management officials on social media.
.Previous Discussion (352 AM Friday),
(today through Sunday), A low pressure system centered off the central California coast early this morning will continue to move slowly toward the south through tonight, then move inland into southern California on Saturday, moving more quickly inland for late Saturday night and Sunday.
Satellite imagery shows a long feed of subtropical moisture from the southwest being drawn northward into Santa Barbara and Ventura Counties. To the east of this band of more significant moisture and rainfall, there have been occasional light showers over portions of southwestern California since Thursday evening. Most areas that have received any measurable rainfall have received a few hundredths of an inch to less than one-tenth with only a couple or reports in the mountains to around one-qaurter inch.
Occasional light showers are expected to continue today into this evening. Rain will become heavy at times late tonight with the heaviest and most widespread rainfall expected from before dawn on Saturday into early afternoon Saturday along with a chance of thunderstorms.
South to southeast winds will begin to strengthen before dawn in advance of the strong with gusts Saturday morning morning near the coast to around 35 mph.
(Monday through Thursday), There is increasing model spread in the details over the eastern Pacific into California for next week. The next low pressure system from the northwest is expected to bring more showers some time around Monday into Tuesday. There could be another round later next week sometime around Thursday or Friday. These systems are not expected to be as warm as the system for today and Saturday with snow levels occasionally lowering to around 6000 feet next week.
A Pacific storm approaching from the west will bring occasional mostly light showers today. As the storm moves closer, rain will become heavy at times tonight with the heaviest and most widespread rainfall expected from before dawn on Saturday into early afternoon Saturday along with a chance of thunderstorms. As the storm moves east, showers will gradually decrease for Saturday night and Sunday.
Through Sunday, rainfall for Orange and southwestern San Bernardino Counties is expected to range from around 2.5 inches near the coast to 3 to 5 inches in the mountains. For San Diego County, rainfall is expected to range from around 2 inches near the coast to 2.5 to 3.5 inches in the mountains with locally greater amounts. For the high desert, 1 to 2 inches of rainfall is expected with around 1 inch for the lower deserts. The snow level will remain around 10000 feet through tonight, then lower to around 6500 feet late Saturday night, then rising to around 7500 feet on Sunday.
These rainfall amounts along with the potential for periods of higher intensity rainfall for late tonight into Saturday afternoon could produce debris flows in burn areas, significant ponding of water on roads and highways, and urban and small stream flooding. The current forecast for the San Diego River has the river at Fashion Valley rising to near monitor stage at 10 AM on Saturday, sufficient to flood low-water crossings, and remaining above that level into early afternoon Sunday.
141700z, Currently FEW-SCT below 1000 feet MSL and SCT-BKN around 4- 8 kft throughout the coastal basin. BKN-OVC around 10 kft area wide. Mid-level BKN-OVC cloud bases to lower gradually to 3-5 kft by this evening with occasional MVFR cigs. Additionally, SCT -SHRA continues across the coastal basin and mtns through this evening.
Widespread RA for all areas pushing in from the southwest after 06Z. This will be accompanied by widespread MVFR VIS, intermittent MVFR CIGs, and increasing southerly winds through the coastal basin. Conditions continue to deteriorate after 12Z as SCT +RA and TSRA begin to move in. Intermittent IFR VIS (1-3SM) and lowered CIGs (1000-2000 ft MSL) with any heavier precip. Southerly wind gusts increasing to 20-30 kts through the coastal basin late Saturday morning.
A large low pressure system approaching the region today will move through Saturday and Sunday. Breezy winds from the south 10-15 knots with gusts near 20 knots today will strengthen early Saturday morning to 15-25 knots, frequent gusts to 30 kts with occasional gusts around 35 kts. This will bring steep, mixed seas 5-8 feet throughout the coastal waters. See the Small Craft Advisory for more. Winds become westerly mid-afternoon Saturday and then gradually weaken that evening, though remain breezy through the weekend.
The system will also bring showers over the waters through the weekend, and a chance of thunderstorms Friday night through Saturday night. Additionally, occasional heavy rain Saturday could reduce visibility. A Marine Weather Statement continues for thunderstorm chances Friday afternoon through late Saturday and contains more details.
West swell 4-5 feet will combine with a south wind swell to create elevated surf 4-6 feet with local sets to 7 feet late this evening through Saturday. Additionally, there is a chance (20-30%) for thunderstorms this evening through Saturday.
Ca, Flood Watch from late tonight through Saturday evening for Apple and Lucerne Valleys-Coachella Valley-Orange County Coastal Areas-Orange County Inland Areas-Riverside County Mountains- San Bernardino County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Coastal Areas-San Diego County Deserts-San Diego County Mountains-San Diego County Valleys-San Gorgonio Pass near Banning-Santa Ana Mountains and Foothills.
PZ, Small Craft Advisory from 2 AM to 4 PM PST Saturday for Coastal Waters from San Mateo Point to the Mexican Border and out to 10 nm-Waters from San Mateo Point to the Mexican Border Extending 10 to 60 nm out including San Clemente Island.
