28/951 AM.
Hot and muggy conditions will continue through Friday with a high risk for heat-related illness. Scattered showers and thunderstorms are possible today, with risks of lightning, fire starts, and erratic winds. Temperature and moisture relief will start over the weekend, but will increase again starting Tuesday, with a chance for showers and convection.
(tdy-Sun), 28/951 AM.
***UPDATE***
The threat of showers and thunderstorms this morning has stayed to the north and west of our four counties so far this morning. We are watching an enhancement just off the coast that could clip San Luis Obispo County in the next few hours. For the afternoon hours, with plenty of sunshine and a still tropical airmass, the risks will transition to the more traditional mountain and deserts areas. None of the high-res models show anything forming over our mountains, likely due to the lack of any upper level disturbances to kick it off, but all the other ingredients are there to at least maintain a low risk. If any thunderstorms form, the impacts will be more gusty winds and fire starts, with less concern for heavy rain and flooding.
On the temperature side of the house, it was still very warm last night thanks to this tropical airmass, but less warm than the previous night thanks to less cloud cover. At 9am, the temperature trends have flipped from 5 degrees below 24 hours ago to 5-10 degrees above thanks to the far more abundant sunshine. Expecting this trend to continue and increase, with a hot and muggy day on tap. The current suite of Heat Warnings and Advisories will remain in play as a result.
The big decision for today will be what to do with tomorrow. Temperatures and moisture will be down from today. It will be a big drop for San Luis Obispo and Santa Barbara Counties. For Los Angeles and Ventura Counties, that drop will only be a little, with the big drop on track for Sunday. As such, will be considering Heat Advisories to cover the period from after the current warnings expire to the end of the day on Saturday. The area most likely to see these advisories are the valleys and inland coastal areas, but will flesh that out in the next hour or two.
***From Previous Discussion***
Hot and muggy conditions will continue today as remnants of Iselle still linger offshore. While elevated convection dropped off overnight over land, thunderstorms were still firing off near where what's left of Iselle roughly 300 miles southwest of LA. Based on the latest satellite imagery it looks like the best chances for any storms or light showers today will be north of Pt Conception. And even though cloud coverage south of there is starting to decrease, PW's are still over 1.5" locally so the muggy-ness will continue at least one more day. And in fact, temperatures in most areas south of Pt Conception should rebound back to very similar temperatures as Wednesday with weak onshore flow and more sunshine. Helping that cause will be the very warm morning temperatures with many areas still in the upper 70s to mid 80s as of 3am.
There is good news though as models continue to favor a significant cooling trend this weekend into early next week. By Sunday or Monday most areas are expected to be near normal or even slightly below normal with humidities much lower as well.
(Mon-Thu), 28/338 AM.
Most of the ensemble models are favoring a trough pattern along the West coast next week, though some height rises are likely by mid week leading to a modest warming trend Wed-Fri. Most of the projections keep highs in check, at most maybe 2-4 degrees above normal, though there is maybe a 10-20 percent chance of highs 4-8 degrees above normal. A return to more muggy conditions is less likely than what models showed yesterday as the next tropical wave off Mexico gets steered well to the west.
28/0518z.
At 0510Z at KLAX, the marine layer was 600 feet deep. The top of the inversion was 2500 feet with a temperature of 32 C.
Overall, moderate confidence in 06Z TAF Package. For most of the period expecting BKN/OVC150.
KLAX, Moderate confidence in TAF. BKN/OVC deck above 10KFT thru at least 28/18Z. Any east wind component is expected to remain below 7 kts.
KBUR, Moderate confidence in TAF. BKN/OVC deck above 10KFT thru at least 28/18Z.
28/929 AM.
Through this weekend, high confidence in small craft advisory (SCA) level winds across the outer waters with short-period choppy seas. These hazardous conditions will reach into the nearshore waters along the Central and into the Santa Barbara Channel at times (especially afternoon/eve). Local gusts may approach 35 kt near Point Conception Saturday evening.
Isolated to scattered showers are expected to continue 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 until 8 PM PDT this evening for zones 341>345-347-348. (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 from 3 PM this afternoon to 3 AM PDT Saturday for zones 645-650. (See LAXMWWLOX). Small Craft Advisory in effect until 3 PM PDT Saturday for zones 670-673-676. (See LAXMWWLOX).
