Marine Weather and Tide Forecast for Borrego Springs, CA

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

Mostly sunny with variable high clouds this afternoon. Surface pressure gradients are weakly offshore to the northeast but trending onshore. A sea breeze has developed and westerly winds extend inland to the mountains. Temperatures are mostly lower than at this time yesterday but still well above seasonal averages.

The upper level ridge over the western US is weakening today as a shortwave trough moves inland to the north. This will bring a return of onshore flow today resulting in lower temperatures near the coast but inland areas will likely still see record-setting high temperatures this afternoon. High temps in the coastal areas will be mostly in the upper 70s, the inland valleys will reach the upper 80s and the low deserts will be in the mid 90s.

Numerical model solutions are in good agreement through next Wednesday with respect to the synoptic pattern. Our weather will be influenced primarily by a low pressure system currently off the coast of northern CA. This system will move inland to our north over the next 48-72 hours reaching the Great Basin by Tuesday. It will bring stronger onshore flow, increased clouds and lower temperatures. The onshore flow will peak on Monday afternoon, with the strongest southwest to west winds producing gusts of 40-50 mph in the wind-prone areas of the mountains and adjacent desert areas. Monday will also be the coolest day, with daytime high temperatures mostly near or a few degrees above seasonal averages, except in the low deserts where temperatures could be as much as 11 degrees above average. High temperatures will be in the 60s near the coast, the upper 60s to low 70s in the inland valleys and high deserts, and in the mid to upper 80s in the low deserts. The onshore flow will bring a return of marine layer clouds/fog to the coastal areas and portions of the inland valleys. The marine layer could return as early as Sunday morning but more likely Sunday night/Monday morning and again on Tuesday.

Temperatures will rebound for Tuesday and Wednesday as the low pressure system moves east into the Rockies and a transient high pressure ridge moves over CA. A brief period of weak offshore flow could also develop for Tue into Wed as a surface high traverses the great Basin.

After Wednesday...Model solutions diverge significantly so confidence in forecast details is lower, but indications are that another trough of low pressure moving inland farther to the north will prevent the ridge from redeveloping and herald a return of broad troughing over most of the western US through next weekend.
This will keep temperatures mostly only a few degrees above seasonal averages as onshore flow prevails, however periods of offshore flow could disrupt the marine layer clouds/fog and temperatures west of the mtns could rise noticeably next Friday and Saturday.

AVIATION
281830Z
Coasts
VFR conditions prevailing through this evening.
Low clouds and FG develop after 06z Sun with CIGs 200-700ft MSL and VIS restrictions 3-5SM. Brief periods of LIFR possible between 10- 16z with 1/4SM in FG and intermittent VV002, highest confidence at KSAN (40-55% chance) and KSNA (40-50% chance) with slightly lower chances at KCRQ (30-40%). Low clouds/FG begin to clear 15-17z, with VFR and SKC-FEW250 after 18z.

Elsewhere
VFR with SKC-FEW250.

MARINE
No hazardous marine conditions are expected through Sunday morning.
Northwest winds increase over the outer waters Sunday afternoon creating hazardous conditions for small craft. See Small Craft Advisory for more details. Winds will ease Monday in the late evening.

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

SGX WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...Small Craft Advisory from 4 PM Sunday to 9 PM PST Monday for Waters from San Mateo Point to the Mexican Border Extending 10 to 60 nm out including San Clemente Island.