A Pacific storm will continue to impact the region through the weekend. Lighter showers through this evening will evolve into heavier and more widespread precipitation late tonight into Saturday, including the chance for thunderstorms. The weather pattern looks like it will remain active with another winter storm expected to impact the region for Monday into Tuesday with another system expected to impact the region later next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
This evening, The Pacific storm centered off the coast of Central CA will continue to bring light rain and showers to the region through tonight. The cloud elements (and rainfall) will continue to move from south to north even as the system moves southward tonight. In the last 36 hours, rainfall reports have ranged from as much as two thirds to nearly an inch in portions of Orange County and on the slopes of the San Bernardino Mountains. Amounts decrease from north to south and from west to east. Portions of southern San Diego County have received only a few hundredths of an inch.
From previous discussion, As the system begins to push inland over the area tonight into Saturday, heavier and more widespread/constant precip will move into the area. The track of the low is more definite now, moving off to the northeast over Southern California into the Desert Southwest by Sunday afternoon. Models show a vorticity maxima and associated IVT surge moving through with this system, leading to highest confidence in the heaviest precipiation falling for many by Saturday morning into the first half of the afternoon. Widespread rainfall is expected to occur for all areas of the region, including the deserts where some areas will receive near one inch of rain in total. Latest hi-res guidance continues to show bands/ribbons of heavier precipitation occurring on Saturday morning into the early afternoon, but there remains 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. Elevated CAPE is also seen across the region during this time period, so embedded thunderstorms cannot be ruled out. As the frontal boundary passes through the area, winds will strengthen as well. Models indicate southerly prefrontal winds gusting near 20-30 MPH for areas near the coast and adjacent valleys and closer to 30-40 MPH across the desert slopes.
Post-frontal precipiation will occur Saturday evening into Sunday for areas along and west of the mountains. Models show some of these being more isolated with moderate amounts of rain at times. Snow levels will remain above 8000 ft with this warm system, but will begin to fall closer to 6,500-7,000 feet by Saturday night into Sunday morning. Snow amounts for mountain towns near these elevations will see near one inch of total snow. Local WRF model shows an interesting set up, with the surface low maintaining itself into Sunday morning bringing additional bands of heavier precipitation. Rain rates near 0.75"/hr are shown in some of these bands, so something to keep an eye on as we move closer in time.
.NEXT WEEK,
After a brief break from precip Sunday afternoon/evening, it is likely that another weather system will move through the area by Monday and Tuesday, as well as an additional system that may approach our region later next week. Confidence is high that the system early next week will impact the region, but exactly where it goes is still in question, where some models depict it to be closer to our area, some further offshore. Whatever the exact path, chances for rain and cooler weather will remain in the forecast for early next week; the forecast also calls for mountain communities/resorts to see some higher accumulations than we expect this weekend. Nbm forecasts show highs well below average with highs in the 50s/60s for many lower elevations/deserts, 30s/40s for higher elevations. Nbm chances are 30-50% to see rain totals over 1 inch for this storm system for areas west of the mountains.
After the early next week storm system passes, a weak ridge may try to nudge into the area by Wednesday. This would bring back some actual sunshine and slightly warmer (still cooler) weather. Models are beginning to align in yet another storm system moving in from the northwest sometime around Thursday or Friday. The details of this system are highly uncertain, but the forecast continues to show an active weather pattern for the foreseeable future.
150500z, Currently observing widespread RA in Orange County and the Inland Empire with some patchy -RA elsewhere. Multiple SCT-OVC layers present from 500-6000 ft MSL. VIS down to 2-5SM in RA. -RA/RA to become intermittent region-wide for the next few hours. Main frontal band to increase rain intensity and coverage from west to east, reaching the coast 10-12z early Sat. Timing for most significant rain 16-22z Sat across the region, featuring +RA, TSRA and periods of south winds gusting to 20-30 kts near the coast and mountains.
Intermittent IFR VIS (1-3SM) and lowered CIGs (1000-2000 ft MSL) with any heavier precip.
Coverage of TSRA and RA (along with associated CIG/VIS restrictions) begins to decrease from south to north after 22Z Sat with winds becoming southwesterly and slowly weakening through the evening.
South winds increase to 15-25 kts overnight with gusts 25-35 kts possible through the daytime hours, especially in the morning. This will bring steep, mixed seas 5-8 feet throughout the coastal waters. See the Small Craft Advisory for more. Winds become southwesterly mid-afternoon Saturday and then weaken slightly to 10-15 kts Saturday night with periods of stronger winds and gusts still possible through Sunday with outflow from showers.
Additionally, heavy rain causing reduced visibility and thunderstorms embedded within the rain will cause for even more hazardous conditions. A Marine Weather Statement thrugh late Saturday contains more details.
Winds strengthen again on Monday ahead of the next storm system. There is still some uncertainty in exact intensity of winds, but gusts in excess of 20 knots are possible along with another round of precipitation.
West swell 4-5 feet will combine with a south wind swell to create elevated surf 4-7 feet with local sets to 8 feet through Saturday. Additionally, there is a chance (20-30%) for thunderstorms this evening through Saturday afternoon. See the Beach Hazard Statement for more.
Ca, Beach Hazards Statement through Saturday afternoon for Orange County Coastal Areas-San Diego County Coastal Areas.
Flood Watch from 4 AM PST Saturday 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.
