04/125 AM.
Significant warming is expected through Sunday as gusty Santa Ana winds continue over Los Angeles and Ventura Counties. Moderate to locally strong winds will continue this morning, then weaken in the afternoon and overnight. A cooling trend will begin Monday with temperatures back to near normal around mid week. There is a chance of rain this coming Wednesday night into Thursday.
(tdy-Mon), 04/924 AM.
Gusty Santa Ana winds with warm and very dry conditions will continue today. So far this morning wind gusts have generally been focused across the typical wind prone mountains/valleys of LA/Ventura counties, but starting to see winds increasing across the Ventura county coastal plain as of 9 am. During the next few hours, will continue to see offshore winds mix down to the lower elevations due to daytime heating, so expect one more slight burst of offshore winds for coastal/valley areas this morning. Current LAX-Daggett pressure gradients running around -5 mb this morning. With upper level wind support weaker today as compared to yesterday, expecting winds in the mountains to be somewhat weaker and more homogeneous in wind speeds as compared to coastal/valley areas as depicted by high resolution model data during the next few hours. Current wind advisories look on track, with gusts mostly in the 30 to 50 mph range this morning. High resolution model data does show offshore winds weakening this afternoon, with a return of onshore winds across coastal areas by 1 or 2 pm.
The overall air mass is warmer than yesterday, and we are projecting temperatures to be considerably warmer than yesterday, with highs mostly in the 80s to lower 90s. In morning update, will be bumping up temperatures some over the Ventura county coastal plain, where maximum downslope warming will likely occur today. Latest temperature guidance shows that portions of the Ventura coastal plain could reach 90 degrees today, especially near Camarillo. The offshore winds will also bring significant drying to the region today, with many wind prone areas seeing humidities lower into single digits today. As a result, the combination of gusty offshore winds, warm temperatures, and very low humidities will bring the risk of additional grass fire activity today (mainly over the interior), with conditions similar to what we saw yesterday with the Crown Fire near Acton. For tonight, some of the latest model guidance showing a weak eddy circulation developing, brining the potential for some marine layer low clouds and fog returning to portions of the LA county coast by Sunday morning.
***From previous discussion***
On Sunday the sea breeze should result in several degrees of cooling along the coast and in the coastal valleys, while further inland the interior valleys and deserts may see a degree or two of warming.
Looking into Monday, the cooling trend that began on Sunday will continue, although highs will still be a few degrees above seasonal normals. Models are indicating low clouds and fog over the coastal areas by Monday morning.
(Tue-Fri), 04/125 AM.
After the slight cool down early in the week, temperatures are expected to level off Tuesday and Wednesday at around 4-8 degrees above normal. Skies will be mostly clear, except light to moderate onshore flow will create areas of low clouds and fog near the coast each night to morning period.
Models continue to indicate at least a 60% chance of rain area- wide late Wednesday night into Thursday. A majority of the solutions are showing around one third to half an inch of rain over Ventura and LA Counties, with totals decreasing further north over Santa Barbara County (up to 0.25 inch) and San Luis Obispo County (0.15 inch or less). There are some models delaying the rain until Friday or Saturday, but lower confidence in these solutions. Otherwise, expect cooler daytime temperatures in the 70s Thursday through Saturday.
04/1556z.
At 1600Z at KLAX, there was a surface-based inversion. The top of the inversion was 1900 feet with a temperature of 21 degrees Celsius.
Overall for the 18Z TAF package, high confidence in CAVU conditions through the period for KPRB, KSBP, KSMX, KSBA, KOXR, KCMA, KBUR, KVNY, KPMD and KWJF.
For KLAX, KSMO and KLGB, high confidence in CAVU conditions through this evening, but low confidence in forecast return of CIG/VSBY restrictions after 10Z.
Moderate offshore winds will continue through early afternoon with light LLWS and turbulence likely over the foothills and mountains.
KLAX, Overall, moderate confidence in 18Z TAF. High confidence in CAVU conditions through this evening. For tonight, there is a 50% chance that CIG/VSBY restrictions do not develop in the 10Z-18Z time frame. No significant easterly wind component is expected.
KBUR, High confidence in 18Z TAF as CAVU conditions are expected through the period.
04/855 AM.
For the Outer Waters, moderate to high confidence in current forecast. Through Sunday, high confidence in winds and seas remaining below Small Craft Advisory (SCA) levels. For Monday and Tuesday, there is a 60-70% chance of SCA level winds across all the Outer Waters. On Wednesday, there is a 60-70% chance of SCA level winds across PZZ673/676, but only a 20-30% chance of SCA level winds across PZZ670.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Through Sunday, high confidence in winds and seas remaining below SCA levels. For Monday through Wednesday, there is a 50-60% chance of SCA level winds in the afternoon and evening hours.
For the Inner Waters south of Point Conception, moderate confidence in current forecast. Through early this afternoon, there is a 60-80% chance of SCA level northeast winds from Ventura southward to Santa Monica, with a 30% chance of Gale Force gusts to 35 kt nearshore between Point Mugu to Ventura. There is also a 50-60% chance of SCA winds across the San Pedro Channel. High confidence in winds diminishing below advisory levels this afternoon and remaining below SCA levels through Sunday, along with sub-advisory seas. For Monday through Wednesday, there is a 40-60% chance of SCA level winds, especially on Tuesday and Wednesday. The stronger winds are expected to be across the western sections of the southern Inner Waters.
Ca, Wind Advisory remains in effect until 3 PM PDT this afternoon for zones 88-354-355-358-371-372-374-380. (See LAXNPWLOX). Wind Advisory in effect until 3 PM PDT this afternoon for zones 369-375-379. (See LAXNPWLOX). PZ, Small Craft Advisory in effect until 3 PM PDT this afternoon for zones 650-655. (See LAXMWWLOX).
