Warm and dry through early next week. Weak to moderate offshore flow today and Saturday will weaken for Sunday through Wednesday. A slow cooling trend begins Monday, with more substantial cooling and increasing precipitation chances late next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION, MARINE, AND BEACHES DISCUSSIONS,
Skies are clear this morning under weak offshore flow. Satellite water vapor imagery shows a vort max digging south into the lower Colorado River Valley with some weak mountain waves becoming evident in the lee of the San Bernardino Mountains. So far offshore winds remain fairly weak with isolated gusts 25-30 mph in the Cajon Pass. Surface pressure gradients are trending stronger offshore to the Great Basin, but are weak to the Mojave Desert (-1.8 mb SAN-DAG). Expect gradients and winds to strengthen as the upper trough continues to dig south - peaking at around 25-35 mph with local gusts to 40 mph in the wind-prone passes, canyons, and coastal mountain slopes later this morning into the afternoon.
Pressure gradients strengthen slightly on Saturday, especially to the east, though we begin to lose some of the upper level support from the nearby trough. Not much change in wind strength for the northern areas expected, though they will be stronger below the San Gorgonio Pass and the coastal slopes of the San Diego County mountains as winds turn more easterly. Offshore winds weaken on Sunday. Otherwise warmer and drier this weekend with highs around 5-15 degrees above normal for the coastal areas and valleys, and near to around 5 degrees above normal elsewhere. Sunday is forecast to be the hottest day, when highs for inland coastal areas and the western valleys will be in the upper 80s to around 90 degrees.
Subtle cooling takes place Monday and Tuesday as the upper ridge begins to weaken and a cut-off low moves by to the south. Weak ridging builds in ahead of a digging trough off the coast on Wednesday, maintaining temperatures around 5-10 degrees above normal. Forecast for later in the week remain highly uncertain. For Thursday, around 52% of the ensemble space maintains ridging over the Southwest for continued warm and dry weather, while the remaining 48% show at least weak troughing across the West Coast for cooler weather and a slight chance of precipitation in So Cal. Differences in the upper pattern continue into Friday, with around 20% of the ensemble members still showing a ridge and dry weather. Even amongst the clusters with some form of troughing, the position of the jet and moisture/heavier precipitation has a lot of north-south variation, though general consensus is for light (if any) precipitation here.
061800, Clear and VFR conditions through Saturday. Offshore northeast winds strengthen over the next two hours with gusts 30-45 kts for coastal slopes, adjacent foothills, and through mountain passes. Pockets of LLWS before the stronger winds surface. Gusts 15- 30 kts for portions of the valleys (KONT, KSBD) and lower deserts (KPSP, KTRM). Some decrease after 02z, increasing the LLWS where sfc winds taper off. Similar to slightly less wind strength on Saturday.
No hazardous marine conditions are expected through Tuesday.
High tides will exceed 7 feet each morning through Tuesday, peaking Sunday and Monday at 7.4-7.6 feet. A northwest (290 degree) swell (2- 3 foot) arrives this afternoon/evening with a period of 14-15 seconds. This will keep surf elevated to 3-6 feet along west-facing beaches through Tuesday, with 3 foot waves more likely along south- facing beaches. This NW swell may even see an increase to 3-4 feet on Monday, which could bring breaking waves up to 7 feet.
The combination of high tides and elevated surf will likely generate minor coastal flooding, with chances for moderate coastal flooding along more west-facing beaches where surf will be higher. A Coastal Flood Advisory remains in effect from through noon Tuesday and contains more details.
Reminder, tides mentioned have been corrected to reflect the current trends in actual tide observations.
Ca, Coastal Flood Advisory until noon PST Tuesday for Orange County Coastal Areas-San Diego County Coastal Areas.
PZ, None.
