Marine Weather and Tide Forecast for Rancho Santa Fe, CA

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

Update: Models are still on track with showing the ridge becoming more amplified to our east, as the weak troughing begins to transition out of the region over the next few days. The marine layer is going to remain rather shallow and mostly confined to the coastal areas, with patchy fog possible into the inland areas by later tonight and though tomorrow morning at around 1000 ft MSL.
This should quickly scatter out by tomorrow morning shortly after sunrise. The strong high pressure in place will result in temperatures remaining on the warmer side through Thursday and rather hot through Wednesday, then there will be increased onshore flow towards the later part of the week as we begin to become more influenced by the trough upstream, with a cooldown going into next weekend.

(Previous discussion submitted at 132 PM):

Hot conditions will continue for inland areas through Wednesday with widespread moderate HeatRisk in the inland valleys, mountain foothills, and deserts. This afternoon, moderate to locally major HeatRisk will occur in the low desert. Make sure you're staying hydrated and seeking shade if you're spending time outdoors through the middle of the week. If possible, avoid strenuous outdoor activity during the hottest part of the day (through 5pm). Most model guidance is showing minimal changes in high temperatures between today and Tuesday for inland Orange County, San Diego valleys, and mountains. For inland Orange County and western portions of the San Diego valleys, how much marine layer low cloud coverage develops overnight will have an impact on how hot it gets Tuesday. Currently high resolution guidance keeps low cloud and fog coverage quite patchy overnight, so the forecast is trending towards the hotter end of the guidance. Patchy dense fog is possible, most likely in San Diego county near the coastal mesas. For the Inland Empire, temperatures will see minimal changes through Wednesday, keeping highs between in the upper 90s to just over 100 degrees.

A very gradual cooling is expected in the deserts for Tuesday into the weekend, although highs will remain 5 to 7 degrees above average. The exception is the High Deserts are expected to see a degree or two of warming on Wednesday, before continuing their cooling trend. Widespread moderate HeatRisk will continue through Thursday for the High Desert and Friday for the low desert.

A passing weak area of low pressure will move across central California today, which will strengthen the onshore pressure gradient. That will bring breezy west winds to the desert mountain slopes, below the passes, and into the deserts during the afternoons and evenings. Strongest winds are expected this afternoon and evening with gusts 30 to 45 mph, locally up to 50 mph through the San Gorgonio Pass.

Ensemble guidance is in good agreement that the ridge of high pressure will get pushed east ahead of an incoming low pressure system approaching the Pacific Northwest. The incoming low will bring widespread cooling, a deeper marine layer, and increased winds over the mountains into the deserts. Marine layer low clouds and fog are expected to reach well into the valleys by the end of the week.
There is high confidence in dry conditions with this passing trough.
Near average temperatures will return by Friday, with below average temperatures expected through the weekend.

AVIATION
170330Z
Coast/Valleys
Mostly clear and VFR through the evening.
Patchy low clouds are redeveloping over the waters and will push ashore after 04Z, but only into westernmost valleys overnight and without uniform coverage. Bases will be around 400-600 feet MSL with widespread vis 2-5SM, but near zero over higher coastal terrain and western valleys. Scatter out Tuesday 15-16Z. Low clouds with similar bases and vis will again push north and inland evening after 06Z Wed.

Mountains/Deserts
Clear skies and unrestricted vis through Tuesday. West winds through 08Z with gusts 20-30 kts, locally near 40 kts through the San Gorgonio Pass, leading to MOD UDDFS.

MARINE
Wind gusts around 20 kts in the outer waters this evening near San Clemente Island. Otherwise, no hazardous marine conditions are expected through Saturday.

SGX WATCHES/WARNINGS/ADVISORIES
CA...Heat Advisory until 8 PM PDT Wednesday for Riverside County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Mountains-San Diego County Valleys.

Heat Advisory until 8 PM PDT Tuesday for Orange County Inland Areas-Santa Ana Mountains and Foothills.

PZ...None.