Near to slightly below average temperatures expected today and tomorrow, with a cooling trend into the end of the week. Unsettled weather is expected for the weekend with increased winds and chances of precipitation. Tides will remain elevated through much of this week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
At noon, temperatures were running within a few degrees of what the temperatures were at noon yesterday. Cooling is expected to start to spread inland as onshore flow gradually increases over the next few days. Widespread below average temperatures are expected through much of this week with highs on Saturday and Sunday running 10 to 20 degrees below average for inland locations. Patchy marine layer low clouds and fog may develop tonight into Tuesday morning near the coast. Low cloud and fog coverage is expected to become more widespread for Tuesday night into Wednesday and will remain persistent each night and morning through the week.
The weather becomes unsettled for the second half of the week with the center of a closed low near the Pacific Northwest coast for Thursday through Sunday. A nearly zonal subtropical jet stream from the central and eastern Pacific into northern Baja will strengthen for Friday and Saturday, possibly transporting a low pressure into northern Baja or far southern California some time around late Saturday into Sunday. There remains a lot of uncertainty in the details of the forecast this weekend, but there is increasing confidence that the bulk of the precipitation won't arrive until Sunday. That being said, periods of on and off light showers may develop as early as Friday or Saturday. Given the uncertainties on if the bulk of the moisture will be transported into Southern California or northern Baja, there is quite a range of potential rainfall totals. The GFS has been trending wetter, with the bulk of the moisture plume closer to Southern California. On the other hand the ECMWF solutions continue to show the bulk of the moisture to our south and east. For context, the range of potential outcomes for 24 hour precipitation totals Sunday are 1.5 to 2.5 inches on the high end and near 0.10 to 0.25 inches on the low end.
In addition to rain, winds are expected to increase over the mountains and deserts. There remains uncertainty in the wind speeds, which will largely be determined by the track of the system. This looks like a warm system, which will keep the snow level near and about 8500 ft. Interested parties should continue to monitor the forecast in the coming days due to the moderate to high uncertainty in the details.
261730z, Mostly clear and VFR conditions today and tonight across the region. Except for patchy coastal low clouds based 700-1200 feet MSL after 08Z Tuesday, leading to a 15-30% chance of cigs at coastal airports Tuesday morning. Cigs that occur are expected to be intermittent, likely not lasting more than an hour, and fully scatter out by 15Z.
No hazardous marine conditions are expected through Friday, except for a few wind gusts exceeding 20 knots in the outer coastal waters late this afternoon and evening.
High tides during the late mornings will generate significant coastal flooding this week. Tides will be anywhere from 1.5 to 1.7 feet above astronomical predictions, likely raising high tides above 8 feet, peaking Tuesday morning. A Coastal Flood Warning contains the details.
Ca, Coastal Flood Warning until 1 PM PDT Thursday for Orange County Coastal Areas-San Diego County Coastal Areas.
PZ, None.
