Marine Weather and Tide Forecast for Temecula, CA

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

Visible satellite at 9 AM was showing areas of low clouds over the ocean with areas of high clouds moving east to west across the area.
The 12Z sounding from NKX was showing 1.44 inches of precipitable water. ECMWF ensemble output shows precipitable water values peaking this afternoon, decreasing slowly on Friday, with a greater decrease for Saturday and Sunday. Showers and potentially a thunderstorm or two may develop this afternoon over the mountains.
Most of the convection looks to stay elevated, which translates to limited impacts at the surface, especially when it comes to rainfall. The reasonable worst case scenario rainfall rate for this afternoon is 0.40 inches per hour, with those amounts expected to be quite isolated and in the mountains if they do occur. An upper level low will move north and east from Baja into southeastern California overnight. This could generate some light showers in and west of the mountains overnight and early Friday morning. A few lightning strikes may occur, but overall no impacts expected.

Even with some decrease in precipitable water Friday, thunderstorm chances look higher due to better diurnal heating Friday afternoon.
High resolutions model guidance is indicating thunderstorms developing over the mountains and locally into the High Desert.
Areas of moderate to heavy rain look more likely with thunderstorm activity Friday afternoon. Rainfall rates are expected to be 0.30 to 0.50 inches per hour, locally up to 0.75 inches. Frequent lightning and areas of flooding look to be the main impacts.

High resolution guidance is indicating isolated lighter showers may develop over the mountains Saturday afternoon, with peak rainfall rates around 0.25 inches per hour. Dry conditions are expected to return Sunday and continue into the middle of next week.

High temperatures for today and Friday will be a few degrees cooler for the deserts with today the likely cooler day. Warming is expected for the deserts Saturday. The deserts will warm a few more degrees on Sunday with most areas a few degrees cooler for early next week. Night and morning coastal low clouds will spread into portions of the western valleys late each night.

AVIATION
171645Z
Coast/Valleys
SCT-BKN clouds AOA 10K ft MSL continuing into the afternoon in the valleys and VCTY KSAN. but likely more widespread than tonight, with similar bases will push ashore after 18/02Z. Highest confidence in BKN-OVC cigs will be across San Diego County. Otherwise, 15-20% chance for thunderstorms and rain showers to move westwards off the mountains into the eastern valleys 18-01Z today.

Mountains/Deserts...SCT-BKN clouds 10000-15000 feet today. ISO-SCT SHRA/TSRA over the mtns after 18Z today, most rain showers elevated.
Highest chances through late this afternoon, but an isolated storm is possible overnight. Associated wind gusts, UDDFS, and VIS restrictions possible with any storm that develops.

MARINE
No hazardous marine conditions are expected through Monday.

BEACHES
A moderate period south-southwesterly swell (2-3 feet at 15-16 seconds) will continue to generate elevated surf and a high risk of rip currents through today. Surf of 3-5 feet expected with sets to 6 feet possible, primarily on southerly facing beaches. Swell and surf will begin to lower on Friday.

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



SGX WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...None.