24/832 PM.
Temperatures will remain above normal across all valleys and interior locations through this weekend. Persistent marine layer will keep temperatures on the cooler side for coastal areas south of Point Conception through at least Thursday. By the weekend, weak offshore flow with temperatures ten to twenty degrees above normal are expected.
(Tue-Fri), 24/832 PM.
***UPDATE***
Overall, a quiet evening across the CWA. Latest satellite and surface observations indicate areas of marine layer stratus south of Point Conception. The stratus is expected to expand in coverage and move inland across LA county later this evening. A small ULL will help lift the marine atmospheric boundary layer (mabl). This should be sufficient to allow the marine layer to filter into the San Fernando Valley late tonight into tomorrow morning. Adjusted the forecast to match these thoughts. Patchy dense fog is also possible along the Central coast mainly south of Morro Bay.
Another day of daily records broken (Max Temperatures):
Palmdale Airport 90 (broke old record of 86 set in 2022) Lancaster 91 (broke old record of 86 set in 1956) Sandberg 78 (broke old record of 76 set in 2014)
The marine layer will keep coastal locations near normal through Thursday, while the interior will remain warm (15-20 degrees above normal).
The ULL to the south will move over eastern portions of our CWA on Wednesday. This will actually provide modest upper level support. Overlapping of low to moderate northerly flow Wednesday night into Thursday morning will bring winds close to advisory levels along the I-5 corridor. 30% chance of wind advisories being issued.
***From Previous Discussion***
High pressure aloft over the eastern Pacific continues to divert all incoming storms well to the north. At lower levels the pattern is more complicated. South of Pt Conception a persistent marine layer around 1500 feet deep will continue at least another day or two, keeping coastal areas on the cooler side. However, by Thursday or Friday, pressure gradients are expected to shift at least slightly offshore and possibly as much as 3-4mb, leading to several degrees of warming and the departure of the marine layer. Still some uncertainty with temperatures there given the spread in gradients, but a majority of the ensembles show a strong enough offshore signal that should support a return of 80s to most coastal areas. Meanwhile, valleys and interior areas will continue to see temps at least 15-20 degrees above normal with a roughly 5 degree warm up between Wednesday and Friday. A return of gusty north to northeast winds across the mountains for the latter half of the week may require a low end wind advisory or two, particularly Thursday night.
Along the Central Coast, offshore flow off the Santa Lucias peaked Monday and is weakening today. Temperatures are still well above normal inland but along the coast a significant cooling trend has already begun. Expecting additional cooling there Wednesday with even a 60-70% chance of some patchy dense fog along the coast, mainly south of Morro Bay. However, a return of light to moderate offshore flow is expected again Thursday, bringing 80+ degree temps to many areas as well as some northeast winds at times. Cooler temps likely Friday, though inland areas will still be well above normal.
(Sat-Tue), 24/147 PM.
Well above normal temperatures are expected to continue through the weekend with light offshore flow and 500mb heights still above the 90th percentile for this time of year. Overall, most areas in the 80s and 90s. Not quite hot enough for heat advisories based on the forecast high and low temps, but if offshore flow is stronger than expected or temps are a few degrees warmer than some heat advisories may be needed.
A cooling trend will begin Monday as the upper level pattern shifts towards troughing over the eastern Pacific. And finally a chance of rain next Tuesday and Wednesday. Ensembles have been slowly increasing rain amounts, in line with what the AI models have been suggesting. Still likely not a major storm for Southern California, but pretty decent for April. Latest projections are showing around an inch along the Central Coast and a half inch for southern areas.
***OF NOTE***
This has be a phenomenally warm month. Using the forecasted high temperatures for DTLA for today (the 24rd) to the 31st along with the max temps that have already occurred, the DTLA average max temp for the month would be 82.0 degrees. This would handily eclipse the previous record holders:
79.1 degrees in 2015 76.7 degrees in 2017 76.0 degrees in 1931 75.8 degrees in 1934 75.7 degrees in 1959
24/2347z.
At 2318Z at KLAX, the marine layer was 900 feet deep. The top of the inversion was at 2200 feet with a temperature of 22 C.
High confidence TAFs for KPRB, KPMD, & KWJF.
Moderate confidence in remaining TAFs.
Timing of CIG/VSBY restrictions may be off +/- 2 hours. Cig hgt could be off by +/- 200 ft.
Low confidence in KSBP and KSMX with a 30-50 percent chc of LIFR/VLIFR conds 10Z-17Z.
KLAX, Moderate confidence in TAF. Arrival and clearing times of CIGs could be off by +/- 2 hours. Generally expecting IFR CIGs (005-009) with MVFR vsbys (3 to 5sm). There is a 20% chance of LIFR conditions 004 with 2SM. No significant east wind component is expected.
KBUR, Moderate confidence in TAF. 70% chance of LIFR to low-end IFR conditions from 25/08Z-16Z. No wind impacts expected.
24/244 PM.
High confidence in Small Craft Advisory (SCA) winds and steep seas expanding through Wednesday over offshore waters from the Central Coast down to San Nicolas Island. It will remain windy through Thursday Night and will likely weaken quickly and significantly on Friday. The winds peak Wednesday afternoon through Thursday morning, when there is a 40% chance for low-end Gales.
The nearshore waters of the Central Coast will see some of those winds and seas, with a 60% chance of reaching SCA during the peak.
High confidence in the rest of the waters being without a SCA through at least Friday.
While some fog will remain possible, visibilities will likely stay above 1 mile.
Ca, NONE. PZ, Small Craft Advisory in effect from noon Wednesday to 9 PM PDT Thursday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 9 PM PDT Thursday for zones 670-673. (See LAXMWWLOX). Small Craft Advisory in effect from 2 PM Wednesday to 9 PM PDT Thursday for zone 676. (See LAXMWWLOX).
