19/349 PM.
A significant cool down is expected across southwest California through the middle part of the week. Widespread rain is likely Tuesday night or Wednesday through Thursday with a chance of thunderstorms.
(tdy-Thu), 19/158 PM.
A return to onshore flow along with high pressure moving east has cooled temperatures several degrees in all areas except the deserts. Cooling in all areas will continue through Thursday as the first traditional (non-tropical) storm approaches. Expecting at least a few more degrees of cooling Tuesday, bringing all areas into below normal territory for the first time in several days.
A pretty potent storm for October appears to be headed towards southern California Wednesday and Thursday. The storm is currently off the Oregon coast and most model solutions show that it will continue to slide south along the California coast before turning inland somewhere between central and southern California Thursday. It is partially cutoff from the stronger jet near the US/CA border, which does introduce some uncertainties with timing and rainfall amounts. In addition, assuming the storm drops as far south as many of the solutions are now indicating, there is an increasing risk for scattered convective activity and locally heavy rainfall, especially Wednesday night into Thursday, which means likely a large variance in rainfall rates and totals. Current projections indicate at least a half inch of rain for the two days, with most areas closer to an inch and some as high as 2 inches. Can't even rule out some locally higher amounts with stronger cells particularly south of Pt Conception. Peak rain rates up to .75"/hr are certainly possible and a flood watch may be needed. Will see how the storm looks tonight and tomorrow. This storm will likely not produce any snow below 8000 feet.
(Fri-Mon), 19/208 PM.
A return to dry and warmer weather is expected Friday into next week. Most of ensemble solutions show offshore gradients returning by Friday and peaking Saturday and Sunday, though likely about 30-40% of the strength of the previous Santa Ana event, possibly even less than that. So some gusty northeast winds at times and warming temperatures but mostly topping out in the 80s.
19/2348z.
At 2300Z at KLAX, the marine layer was 900 ft deep. The top of the inversion was at 1600 ft with a temperature of 23 C.
High confidence in VFR TAFs at KBUR, KVNY, KPMD, and KWJF. However, there is a less than 10% chance for brief LIFR-IFR conditions at KBUR/KVNY 13Z-17Z.
Moderate confidence in IFR-MVFR conds at KSBP, KSMX, KSMO, KLAX, & KLGB. Timing may be off +/- 3 hours with CIG height +/- 200 ft of TAF. 15% chance for no low clouds.
Good confidence in TAFs for KSBA, KOXR, and KCMA. There is a 15% chance for brief IFR-MVFR conds 20/10Z-18Z.
KLAX, Moderate confidence in TAF. OVC007-010 may arrive as early as 08Z or as late as 13Z, with a 15% chance for no low clouds. No significant east wind component expected.
KBUR, High confidence in TAF. Less than 10% chance for brief LIFR-IFR conds 20/13Z-17Z.
19/133 PM.
Small Craft Advisory (SCA) northwest winds will be common across portions of the outer waters through tonight, with localized SCA wind gusts into the western portion of the Santa Barbara Channel.
Tuesday will feature relatively quiet conditions, then a storm system will move into the coastal waters as early as late Tuesday evening. This system will impact the area through Thursday, impacting the northern waters first. While at this point it doesn't appear as though this system will bring significant winds, there will likely be some enhanced southerly flow Wednesday, which may require SCAs to be issued (including nearshore). In addition to the enhanced southerly flow, boaters can expect rain and a chance of thunderstorms and isolated waterspouts. With any thunderstorm there is the threat of lightning, gusty and erratic winds, small hail, and choppy seas. As the system leaves the area Thursday, fairly widespread west to northwest SCA winds will impact much of the coastal waters, creating steep, choppy wind waves.
Then a weak to locally moderate Santa Ana Wind event is likely this weekend, with some localized SCA level gusts possible nearshore in favored areas nearshore adjacent to Ventura and LA Counties.
Ca, Beach Hazards Statement in effect through late Thursday night for zones 354-362-366. (See LAXCFWLOX). PZ, Small Craft Advisory in effect until 3 AM PDT Tuesday for zones 673-676. (See LAXMWWLOX).
