San Clemente Island CA to Guadalupe Island from 60 NM offshore west to 120W Offshore Forecast
|Tonight And Mon...Nw Winds 15 To 20 Kt. Seas 5 To 7 Ft.|
|Mon Night...Nw Winds 15 To 20 Kt. Seas 4 To 6 Ft.|
|Tue...Nw Winds 10 To 20 Kt. Seas 3 To 6 Ft.|
|Tue Night...Nw Winds 15 To 25 Kt. Seas 3 To 6 Ft.|
|Wed...Nw Winds 10 To 20 Kt. Seas 4 To 6 Ft.|
|Wed Night...Nw Winds 15 To 20 Kt. Seas 4 To 5 Ft.|
|Thu...Nw Winds 10 To 15 Kt. Seas 4 To 5 Ft.|
|Thu Night...Nw Winds 10 To 20 Kt, Becoming 10 To 15 Kt. Seas 4 To 6 Ft.|
|Fri...Nw Winds 5 To 15 Kt. Seas 4 To 6 Ft.|
|Fri Night...Nw Winds 10 To 20 Kt. Seas 4 To 6 Ft.|
| Area Forecast Discussion|
National Weather Service San Diego CA
114pm PDT Sunday July 3 2022
The trend of cooler temperatures with early morning low clouds and fog continues through Wednesday with an upper level trough over the Eastern Pacific. Highs are projected to be a few degrees below seasonal normals each day through Wednesday along the coast, while the inland valleys, mountains, and deserts will experience daytime highs anywhere from 6 to 12 degrees below normal for early July. Strong high pressure over the Central US expands westward later this week, putting an end to the cooling trend and opening the door for a significant warm-up leading into the weekend.
For Extreme Southwestern California Including Orange... San Diego...Western Riverside and Southwestern San Bernardino Counties
An upper level low and attendant trough will remain entrenched over the Eastern Pacific through midweek, with the resulting lower heights/thickness values as well as extended onshore flow prolonging the stretch of relatively cool temperatures for early July. Marine layer low clouds and localized areas of fog, stemming from onshore flow and a persistent low-level inversion based generally between 1500-2000 FT MSL, will also mitigate daytime warming for a few hours each morning not just at the coast, but well into the inland valleys. The end result of these factors will be daytime highs topping out several degrees below seasonal normals. This will be most noticeable in the inland valleys and mountains where highs 5-10 degrees below normal will occur.
The upper low over the Eastern Pacific deepens slightly per ensemble height anomaly guidance, which will likely be followed by an increase in the onshore surface pressure gradients with ECM/GFS guidance suggesting onshore gradients of 9-13mb between SAN-LAS. This will favor wind gusts of 30-50 mph over the mountains, with localized gusts of 50-55 mph below mountain passes and into the desert foothills this afternoon and evening. The low will then weaken slightly and retrograde back westward as a strong ridge over the Central US begins to amplify the upper level pattern, leading to weaker surface gradients and progressively weaker winds through Monday and Tuesday.
The aforementioned Central US ridge will strengthen late this week, with ensemble 500mb height guidance suggesting the development of a 594-597dm high centered over the Central to Southern Rockies and High Plains by the weekend. The resultant increasing heights/thicknesses allow for temperatures from the inland valleys across the mountains and especially into the deserts to increase through the weekend. The ridge will remain far enough eastward to allow for at least some weak troughing and onshore flow, which will keep temperatures relatively cool near the immediate coast. The takeaway from this setup is temperatures near seasonal normals at the coast through the weekend, while all other inland areas top out 5 to 10 degrees above normal through Sunday. This translates to temperatures routinely exceeding 110 degrees in the low deserts with temperatures exceeding 100 degrees across portions of the Inland Empire as well as the high deserts.
There remains an outside chance that some monsoonal moisture may begin to work its way into the area early next week after the upper high weakens a bit. At this moment, RH at both 500 and 700mb look to remain rather dry, not nearly enough to support any substantial convection or rain chances. A few ensemble members are holding onto the potential for some enhanced moisture aloft, enough to generate some rain chances over the mountains next week. Confidence remains very low in any rain chances given the minority of members suggesting rain as well as timing differences between them.
Gusty northwest winds 15 to 20 kt with gusts to 25 kt expected across the outer coastal waters this afternoon and evening. Winds will weaken overnight. Gusts near 20 kt will develop near San Clemente Island each afternoon Monday through Wednesday.
Westerly winds increase again later this afternoon, leading to peak wind gusts of 30-50 mph coinciding with minimum RH of 8-15%. This will lead to elevated fire weather conditions from the mountains eastward, locally critical fire weather conditions in the windiest spots. Progressively weaker winds are anticipated on Monday and Tuesday, while RH steadily increases. Areas west of the mountains will experience light winds and elevated RH with the marine layer in place. The warming trend expected later this week will certainly lead to lower RH across many inland areas, especially from the Inland Empire into the mountains and desert foothills.
Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions.
NOAA San Diego CA Office: Watches - Warnings - Advisories
CA...Wind Advisory until 4am PDT Monday for San Gorgonio Pass Near Banning.
PZ...Small Craft Advisory until midnight PDT tonight for Waters from San Mateo point to the Mexican Border Extending 30 to 60 nm out including San Clemente Island.