16/933 AM.
High pressure and offshore flow will bring very warm and dry conditions across the region through the weekend along with locally gusty northeast winds at times across Los Angeles and Ventura Counties. A slow cooling trend will begin today, but above normal temperatures are expected at least into early next week.
(tdy-Sun), 16/943 AM.
***UPDATE***
Temperatures are starting off cooler today as a shallow marine layer managed to move onshore with even some dense fog along the Central Coast down to Ventura and Oxnard. This was possible due to a slight weakening of offshore flow. However, gradients have already started trending back offshore and there are some gusty east winds up to 45 mph across the Santa Susanna Mountains as well as the San Gabriel Mountains. There's even some gusts to around 35 mph in Porter Ranch in the northwestern portion of San Fernando Valley north of Highway 118.
Despite the cooler morning temps, expecting today to be another warm day across most areas with the possible exception of the immediate coast. Highs overall expected to be in the mid 70s to mid 80s, with similar temps Saturday.
***From Previous Discussion***
NW winds across the outer waters have pushed a large mass of ocean stratus to the Central Coast and then down south where it is fueling a weak eddy. The eddy is pushing some of the stratus up to the north towards Long Beach. There is also a stratus push through the SBA channel which has brought some clouds to the SBA south coast and might also bring clouds to the VTA coast towards dawn. There is also a weak Santa Ana driven by 3 to 4 mb of offshore flow both from the N and E, while there will be some gusty winds though passes and canyons almost all gusts will be below advisory criteria. There will be advisory level gusts across some isolated mtn ridgetops. Hgts will fall a few dam and with the marine layer now present most areas will see 1 to 3 degrees of cooling. Max temps will still be well above normal with cst/vly highs in the mid 70s to lower 80s (beaches upper 60s and lower 70s).
The offshore flow to the east is forecast to double to near 6 mb Saturday morning while the offshore push to the south will remain near 3 mb. There is not much (if any) upper support so do not think there will be advisory level gusts. Do think the winds will be strong enough to keep the western Malibu to the SBA south coast free of clouds. That said the ensemble based cloud forecast brings low clouds to every coast and even some lower vlys. Will have to continue to evaluate this tug of war between the marine layer and the offshore flow through the day today to get the correct cloud forecast. The marine layer is shallow enough that where ever low clouds due appear they will arrive with dense fog. Max temps should be similar to today's, although again if the cloudier forecast comes to fruition max temps may be cooler across the coasts.
Onshore trends will bring more marine layer clouds to the csts on Sunday. There will still be enough offshore flow to produce some morning canyon winds but nothing too strong. Max temps will fall 1 to 3 degrees on an unremarkable weather day.
(Mon-Thu), 16/1235 AM.
More seasonal but very likely dry weather is on tap for next week. At the upper levels a weakening ridge will continue over the state. Hgts will start out around 576 dam but will fall to about 570 dam byt Thursday. At the sfc weak offshore flow will persist through mid week but will then turn weakly onshore.
Skies will be mostly clear save for the marine layer stratus. The offshore flow will limit the low clouds on Mon and Tue. There will be more robust low cloud coverage on Wed/Thu as the offshore flow turns onshore.
The lowering hgts and the onshore trends will bring 4 days of cooling to the area. Monday's highs across the csts and vlys will be in the upper 60s and 70s. By Thursday, however, those areas will see max temps only in the 60s or a degree or 2 below normal.
Ensemble based forecasts have backed off on any rain chc through next Friday. Both the AI-EC and AI-GFS are dry through the 29th and show a slight rain signal during the 30th and 31st of the month.
16/1638z.
At 16Z at KLAX, there was a surface-based inversion. The top of the inversion was 2700 feet with a temperature of 21 degrees Celsius.
For 18Z TAF package, high confidence in KBUR, KVNY, KPMD and KWJF. For coastal sites, as well as KPRB, moderate confidence in 18Z TAF forecast as there is a 20-30% chance of LIFR/VLIFR conditions 10Z-18Z.
KLAX, Overall, high confidence in 18Z TAF as CAVU conditions are anticipated through the period. However, there is a 15-20% chance of LIFR/VLIFR conditions 10Z-18Z. No significant easterly wind component is expected.
KBUR, Overall, high confidence in 18Z TAF as CAVU conditions are anticipated through the period. There is a 30-40% chance of light to moderate LLWS and turbulence after 12Z.
16/838 AM.
Dense fog with low visibilities impacting most of the coastal waters from the Central Coast to San Nicolas Island, with a patch over the mid-Santa Barbara Channel, and another off the Orange County Coast. Dense fog will likely be around through the weekend, with low confidence on exactly where it will move around.
There is a 20% chance of low-end Small Craft Advisory (SCA) NE winds from Ventura through Santa Monica this morning and again Saturday morning. Otherwise, High confidence in winds staying below Small Craft Advisory (SCA) through at least Monday, with generally small seas.
Ca, NONE. PZ, NONE.
