04/114 PM.
Significant warming is expected through Sunday as gusty Santa Ana winds continue over Los Angeles and Ventura Counties. A cooling trend will begin Monday with temperatures back to near normal around mid week. There is a chance of rain sometime between Thursday and Saturday.
(tdy-Tue), 04/143 PM.
Gusty Santa Ana winds are brining warm and very dry conditions to the region today. The Santa Ana winds have focused across the typical wind prone corridors of LA/Ventura counties with wind gusts between 30 and 50 mph observed today. During the past hour, starting to see a slight weakening of the offshore winds and this downward trend will continue through the afternoon hours. Current wind advisories are in effect until 3 pm today, and plan to let those expire at that time. Within the next hour, we are also expecting an onshore wind reversal across the Ventura county coastal plain.
The overall air mass is warmer than yesterday, and we are seeing temperatures considerably warmer than yesterday, with highs mostly in the 80s to around 90 degrees. High resolution model data shows the warmest temperatures today (around 90 degrees focused) across the Ventura county coastal plain as well as the western San Fernando valley and San Gabriel Valley. The offshore winds have also brought significant drying to the region today, with many areas seeing humidities in the single digits. As a result, the combination of gusty offshore winds, warm temperatures, and very low humidities will continue to bring the risk of fast moving grass fires this afternoon (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 patchy dense fog returning to portions of the LA county coast by Sunday morning.
On Sunday morning, a weak offshore breeze will continue across the interior of LA/Ventura counties. By Sunday afternoon/evening, a more pronounced return of onshore winds are anticipated across the entire forecast area. While the earlier sea breeze will likely bring some cooling to the coast and coastal valleys, the further inland areas will remain very warm, with possibly an additional 1 or 2 degrees of warming.
Looking into Monday/Tuesday, there will be increased onshore flow with more extensive low clouds and fog returning to the coastal plain and coastal valleys. This will lead to further cooling across coastal and coastal valley areas, but the interior will remain warm.
(Wed-Sat), 04/141 PM.
Little change in temperatures expected on Wednesday with a continuation of onshore flow and marine layer influence near the coast.
Models continue to indicate at least a 70% chance of rain area- wide sometime between Thursday and Saturday. A majority of the solutions are projecting rainfall totals in the 0.25 to 1.00 inch range, but some of the ensemble members (especially ECMWF ensembles) are showing some solutions exceeding 1.00 inch. There are some models delaying the rain until Friday or Saturday, but lower confidence in these solutions. This system is associated with a closed low pressure system. If the closed low does move over the forecast area next weekend (as many solutions indicate), the associated cooler air aloft (with 500 mb temperatures around -23 degrees Celsius) will likely bring some instability which could bring a convective element to the storm, especially considering the higher April Sun angle.
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.
04/1221 PM.
For the Outer Waters, moderate to high confidence in current forecast. Today through Sunday, high confidence in winds and seas remaining below Small Craft Advisory (SCA) levels. For Monday through Wednesday, high confidence in SCA level winds. On Thursday, there is a 30-50% chance of SCA level winds.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Today through Sunday, high confidence in winds and seas remaining below SCA levels. For Monday through Wednesday, there is a 60-80% chance of SCA level winds, mainly in the afternoon and evening hours. On Thursday, there is a 30-40% chance of SCA level winds in the afternoon and evening hours.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. This afternoon through Sunday, high confidence in winds and seas remaining below SCA levels. For Monday through Tuesday, there is a 50-70% chance of SCA level winds across the western half of the Santa Barbara Channel. For Wednesday through Thursday, there is a 60-80% chance of SCA level winds across all of the southern Inner Waters. Additionally, there will be a 20-30% chance of GALE FORCE winds Wednesday night.
There will be a chance of dense fog tonight and Sunday morning south of the Channel Islands.
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, NONE.
