28/205 PM.
Hot and muggy conditions will linger in some areas through Saturday, with widespread improvement by Sunday. More warm tropical moisture could return Tuesday through Thursday.
(tdy-Mon), 28/221 PM.
A shower or thunderstorm could still form over SLO or Santa Barbara County, as well as any mountain or desert location, but the risks will continue to be on the decline through the evening hours before end all together.
The upper level high centered over Arizona, that drove the heat and moisture surge this week, will slowly slide back to the east and over Texas by Sunday. Meanwhile, a slow moving trough to the north will drop deeper into California and linger into next week. This will do two important things. One, it will shut off the tropical moisture feed by Sunday and replace it with a more typical dry southwest flow aloft. This will end the shower and thunderstorm chances and reduce the muggy feeling (but not completely crush it thanks to our very warm oceans that are not going anywhere). Secondly, this will cool the airmass quickly such that over the next 48 hours we will go from high temperatures that are 10-15 degrees above normal to 5-10 degrees below normal. This transition will happen faster for SLO and Santa Barbara County, which in some respects has already begun. For Los Angeles and Ventura Counties however, it will happen slower. Tonight and tomorrow will not feel as hot as the last few days, but it will still feel very warm. With overnight temperatures tonight staying 10-15 degrees above normal, and highs tomorrow still 5-10 degrees above normal on the coastal side of the mountains, decided to go ahead and issue a Heat Advisory for tomorrow over the coastal and valley sections of Los Angeles, Ventura, and southern Santa Barbara County - which goes into effect immediately after the current Extreme Heat Warning ends this evening. This WILL be the last of it and the last straw of our ongoing heat event.
The marine layer should return by Sunday or Monday, but predicting exactly how it will return and where is always an impossible task.
Gusty Sundowner winds will affect southern Santa Barbara County each night through Sunday Night. While the peak remain squared on Saturday Night, decided to put out a low-end Wind Advisory for tonight largely because of models under-predicting these winds over the last few days. Will definitely need an Advisory for tomorrow night.
(Tue-Fri), 28/227 PM.
Tuesday through Friday remains a tale of two potential outcomes. The most likely outcome is for fairly normal conditions in terms of temperature and wind. This includes multiple tropical storms forming off the Baja coast with any effects for us (outside of building surf) staying to the south and west. The not probable but still possible outcome is for moisture from one of those storms to be pulled up through southwest California in that window and bring us some variety of muggy and warm conditions with chances of showers and thunderstorms. The American and European ensemble systems keep this posibility in the 10-20 percent range, and our current forecast largely resembles this. The Canadian model continues to be at odds with the rest, with almost half of its ensemble members producing rain, and about a quarter of them with moderate to heavy rain. Something to keep an eye on.
28/1945z.
At 1847Z at KLAX, the marine layer was 450 feet deep. The top of the inversion was 2400 feet with a temperature of 30 C.
Overall, moderate confidence TAF Package. For most of the period expecting BKN/OVC150. Low confidence in any marine layer clouds forming tonight, and for KSMX there is a 40% chance of VFR conditions through the period. For KPRB, KSMX, KSBP, KPMD, and KWJF there is a 10-20% chance of showers and thunderstorms this afternoon that may produce gusty outflow winds.
KLAX, High confidence in TAF. SCT to BKN cigs above 10KFT are expected to continue for the period, and the east wind component is expected to stay 6 kt or lower.
KBUR, High confidence in TAF. SCT to BKN cigs above 10KFT are expected to continue for the period
28/155 PM.
Through this weekend, high confidence in Small Craft Advisory winds and choppy seas for the outer waters. These hazardous conditions will reach into the nearshore waters along the Central and into the Santa Barbara Channel at times (especially this afternoon/evening and Saturday). Local gusts may approach 35 kt near Point Conception Saturday evening.
Isolated to scattered showers are expected to continue through today across the coastal waters mainly north and west of Point Conception. There is a 10% chance of thunderstorms which could bring the threat of erratic winds, localized rough seas and cloud- to- surface lightning. For next week, most waters are likely to fall below SCA levels Monday and Tuesday. Increasing chances for SCA conditions later in the week but signal isn't strong, moderate at best.
Ca, Extreme Heat Warning in effect until 8 PM PDT this evening for zones 38-87-88-349>358-362-366>376-378>383-548. (See LAXNPWLOX). Heat Advisory in effect from 8 PM this evening to 8 PM PDT Saturday for zones 88-349-350-354>358-362-366>375-548. (See LAXNPWLOX). Heat Advisory in effect until 8 PM PDT this evening for zones 341>345-347-348. (See LAXNPWLOX). Wind Advisory in effect from 6 PM this evening to 6 AM PDT Saturday for zones 349-351. (See LAXNPWLOX). Red Flag Warning in effect until 3 PM PDT this afternoon for zones 340>345-353-375>380. (See LAXRFWLOX). PZ, Small Craft Advisory in effect until 3 AM PDT Saturday for zones 645-650. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Monday for zones 670-673-676. (See LAXMWWLOX).
