San Bernardino, CA 92401 Weather

Synopsis

Cloudier and cooler weather will continue into the weekend. A weather system will move into the area, bringing the chance of widespread rainfall this weekend, heaviest of which will occur late Saturday into Sunday morning. Slightly warmer and drier weather is expected by Monday into at least the middle of next week.

Discussion

FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE: SAN DIEGO: WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES:

A low pressure system currently off the coast of the Pacific Northwest will lead to a greater troughing pattern over the West Coast into the weekend. Today will be dry with scattered clouds and temperatures near to slightly below average. As the low pressure system moves southward, an open wave trough will begin to form bringing in greater moisture from the southwest. PWAT values rise near one inch at San Diego. The marine layer will slowly become saturated tonight into Saturday, where hi-res models continue to show areas of light showers from the coastal slopes of the mountains to the coast. Since these seem to be isolated in nature, the forecast shows around 15-25% chance of rain for these areas Thursday night through Friday night.

A large area of moisture in the form of a subtropical low pressure system that we continue to monitor is slowly forming well off the coast. Models are beginning to agree on a more southerly track with the main swath of the heaviest rains going into Baja California, where IVT values near 300 kg/m/s (weaker values) for SoCal. Nonetheless, bouts of moderate to heavier rain are expected Saturday night into Sunday morning. With the model guidance of a more southerly track of the system, confidence remains high on San Diego County seeing the most precipitation overall, as well as all coastal mountain slopes. Confidence is not as high on rain totals further north, where there is a larger model spread. PWAT will peak near 1.5 inches in San Diego, as the subtropical low and low to the north pass through, so sufficient moisture will be in place.

The interactions between the subtropical low and the low pressure system to the north is still somewhat uncertain, where exact rain totals are still in question. Chances for 1 inch of rain in total over the weekend has stayed pretty consistent across San Diego County (50-60%), closer to 75% in the mountains. These chances decrease across the LA basin near 35-45%. Chances for one half inch in this area increases to 55-65%, 35-50% chance across desert regions. Some heavier bands of showers may occur over San Diego county closer to the core of the subtropical low, which may bring greater amounts locally. In terms of timing, light to moderate showers will push in from west to east sometime on Saturday afternoon into the evening. The period for the heaviest rainfall will be later on Saturday night into early Sunday morning. Rainfall will become more scattered about late Sunday morning through early evening, with peaks of sunshine starting to make a return in parts of the deserts and western LA basin as the system moves eastward.

Dry and sunnier weather is expected by Monday as weak high pressure moves over the area. This will bring a subtle warming trend, though keeping temperatures near normal readings for early November. This weather looks to continue into at least Wednesday. Another low pressure system may form somewhere off the California coast into the latter half of next week. This may bring a slight chance of light showers near the coast, though most of the region looks to stay dry for the rest of the week.

Aviation

291800Z: While clouds scattered out briefly earlier today, BKN-SCT 4000-5000 ft MSL have redeveloped, with much patchier clouds near 2500-3000 ft along the coasts. More BKN low clouds near 3000ft develop and spread across the basin after 01-03z Friday with VCSH more along the coastal areas. Areas of -SHRA with CIGs locally down to 2500 feet MSL expected near the coast after between 08-13z. VCSH chances decreases by 16-19z Friday with lower clouds become more FEW- SCT into the afternoon hours.

Marine

No hazardous marine conditions are expected through Saturday. As a storm system moves through the coastal waters this weekend, shifting winds and seas are likely to increase by Sunday morning, possibly to hazardous levels, lingering into Monday. There is also a slight chance of thunderstorms Saturday night and Sunday morning. Stay tuned for updates.

Beaches

Today's high tide has already peaked earlier this morning at 7.64 feet at La Jolla tidal gauge. The Coastal Flood Warning remains in effect through 1 PM this afternoon to due lingering minor coastal flooding concerns following the high tide. A Coastal Flood Advisory will replace the warning at 1 PM, in effect until 2 PM Friday. Friday's high tide is expected to peak around 7.25 feet near noon Friday which could produce minor coastal flooding as surf is expected to be around 3-5 feet.

The southwesterly swell (3 ft at 15 seconds from 200 degrees) responsible for the marginally elevated surf through the weekend will persist into Monday. As a storm system moves into the area for Sunday/Monday, increased winds could help bolster localized wave sets to 6 feet. While high tides will continue to wane into the weekend, tides will remain over 6 feet which could still lead to minor tidal overflow if breaking waves near 4-6 feet.

Reported forecast tides have been corrected up by 1.4-1.6ft based on recent trends in tidal observations.

Climate

The water temperature at Scripps Pier on Wednesday was another record warm temperature for the date at 73.6 F, 10 degrees above the long-term average for the date. Water temperatures at Scripps Pier have largely plateaued for the past month, though were a little cooler for the middle of October, at a time of year when water temperatures would normally be declining. Hence, the recent stretch of new daily record warm water temperatures day after day after day. The ensemble mean of the ECMWF seasonal forecast from October was for water temperatures along the southern California coast to average 10 degrees F above normal for December through February.

The water level at San Diego during the peak of the highest high tide on Wednesday was the third highest on record for San Diego. The highest water level for today is expected to be around 0.28 feet lower than on Wednesday, which would place it as the 8th highest water level recorded at San Diego. This recent 5-day stretch from Sunday through Thursday of this week will likely include 5 of the 10 highest water levels ever recorded at San Diego.

The record high water levels of this week have been the result of the combination of higher astronomical high tides during the full moon combined with sea levels that are around 17 inches higher than a year ago as a result of thermal expansion of the record warm water from the strengthening El Nino.

Highest water levels at San Diego:

1) Oct 27, 2026: 2.80 feet MHHW (8.52 feet MLLW) 2) Oct 26, 2026: 2.72 feet MHHW (8.44 feet MLLW) 3) Oct 28, 2026: 2.71 feet MHHW (8.43 feet MLLW) 4t) Jul 14, 2026: 2.54 feet MHHW (8.26 feet MLLW) 4t) Nov 25, 2015: 2.54 feet MHHW (8.26 feet MLLW) 6) Aug 02, 2023: 2.53 feet MHHW (8.25 feet MLLW) 7) Dec 13, 2012: 2.45 feet MHHW (8.17 feet MLLW) 8) Oct 25, 2026: 2.40 feet MHHW (8.12 feet MLLW)

Water levels will likely be at least a few inches higher during king tides the week of Thanksgiving and the week of Christmas.

Skywarn

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

Watches, warnings and advisories

CA: Coastal Flood Warning until 1 PM PDT this afternoon for Orange County Coastal Areas-San Diego County Coastal Areas.

Coastal Flood Advisory until 2 PM PDT Friday for Orange County Coastal Areas-San Diego County Coastal Areas.

PZ: None.