Minor cooling continues tomorrow, though above normal temperatures persist. Slight warming next week as weaker high pressure builds back into the region, with temperatures 10-25 degrees above average through at least Friday. Areas of low clouds and fog will spread into the coastal areas each night and morning.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Today through tomorrow night,
At this time, there are some areas of patchy fog along the coastal slopes and within a few of the inland valleys. There are only a few remote locations reporting visibilities of less than a quarter of a statue mile. Be advised if you are commuting this morning along the coast and up to around 10 to 15 miles inland, and especially along the I-15 corridor stretching from Mira Mesa and northward to Fallbrook, as there could be significant visibility restrictions on occasion due to these isolated areas of dense fog.
High pressure conditions remain over SoCal, although the ridge is finally beginning to weaken and shift a little further east as there is troughing upstream propagating towards the region. This is allowing for the return of better onshore flow, which has also brought in more lower level moisture, and therefore has allowed for the marine layer to redevelop over the inner waters and move over with areas of patchy fog this morning. This is relatively shallow and should mix out/dissipate fairly quickly after sunrise over most of the inland areas, and then just perhaps remain right off the coast throughout most of the afternoon, with occasional moments of clouds becoming broken to overcast immediately along portions of the coastline. Elsewhere, temperatures will warm up relatively quickly, although temperatures will be notably cooler in comparison to yesterday west of the mountains with better onshore flow. With passage of the weak troughing to north north and some ridging moving in behind, temperatures will begin to gradually warm tomorrow, with readings being a few degrees warmer for locations west of the mountains, although slightly cooler within the lower deserts.
For tomorrow night, the marine layer will likely be similar in coverage, although since heights are dropping slightly, the low clouds ceiling will lift slightly, which may result in some of the inland areas a little further east being impacted by low clouds/fog through Tuesday morning.
Tuesday through next weekend,
From Tuesday through the end of the work week, temperatures will continue to gradually warm back up with values not as hot as this past week, though still very warm for this time of year, with some locations still having max temperatures at 20 to 25 degrees above the seasonal temperature for this time of year as a negatively tilted ridge axis remains locked in place over the western states. There is still consistency within the ensembles that does reveal that this ridge will begin to break down and weaken as it finally propagates eastward, with weak troughing becoming the dominant feature going into the following weekend, and this should help to bring about some much needed relief for temperatures and hopefully bring them back down to where they should be for this time of year. There is also going to be some mid level moisture that gets advected up ahead of this trough and may provide a slight chance of a shower over the mountains during the afternoon on Saturday, otherwise the region is expected to remain dry through then.
221100z, Low clouds based 400-700 ft MSL currently over San Diego/Orange Counties up to 15 miles inland. This will allow for areas of minor vis reductions (4-6SM) down to sea level (i.e. KSAN, KSNA). Greater vis reductions (1-4SM) for elevated coastal terrain and western valleys. Patchy dense FG where clouds intersect terrain. Clouds scatter to the coastline 15-17Z, but may linger at the beaches through 20Z. Low clouds with similar to slightly higher bases return to coastal areas staring 03-06Z Mon. Vis reductions likely again for elevated coastal terrain and western valleys.
Elsewhere, VFR conditions expected through the period.
Very patchy fog out over the local waters through this morning. Most of the clouds are elevated off the water surface, though local minor visibility reductions remains possible. Otherwise, no hazardous marine conditions expected through Thursday.
Ca, None. PZ, None.
