01/131 PM.
A major and long lasting heat wave will begin Friday and last through all of next week at least with with dangerously hot temperatures.
(tdy-Sun), 01/216 PM.
***A VERY DANGEROUS AND LONG LASTING HEAT WAVE FRIDAY THROUGH AT LEAST NEXT WEEK AND LIKELY EXTENDING INTO THE SECOND WEEK IN OCTOBER***
No significant changes to the short or long term forecasts. A dangerous heat wave will begin Friday and last through at least next week as a strong high pressure system sets up over the eastern Pacific and West coast. Pressure gradients are already starting to weaken today and that trend will continue through Saturday morning, resulting in offshore gradients to the east and north in the -2 to -4 range. So while this is an offshore scenario in October, it's not a traditional Santa Ana as the upper support is not sufficient for persistent gusty winds, though there will be brief periods of some sub advisory level north to northeast winds at times. However, in typical Santa Ana fashion, this heat wave will include the beaches, at least south of Pt Conception.
Temperatures will ramp up quickly Friday by 5-10 degrees and "peak" Saturday, though "peak" is misleading because day to day high temps will likely not change much at least through early next week. During this heat wave, warmer valley highs are expected to be 102-107, Downtown LA 99-103, and coastal areas from Santa Barbara to LA 90-98. These are 15-20 degrees above normal.
It will be warming in SLO and northern Santa Barbara Counties as well but delayed by a day. By the weekend expecting highs away from the beaches to reach the low to mid 90s and lower 100s in the interior. Heat advisories have been issued for these areas Saturday and Sunday. These may need to be extended in certain areas next week but models have been showing just enough cooling early next week to allow the advisories to drop off.
(Mon-Thu), 01/219 PM.
This period will feel a lot like this coming weekend, though there are still some model solutions indicating a little more upper level northeast wind support and subsequently even hotter temperatures. This would be in the Wed-Fri period, so there is the potential for even hotter weather later next week with a better chance of breaking daily temperature records. Longer range models are starting to at least hint at some cooling next weekend.
01/1707z.
At 1625Z at KLAX, the marine layer was 1300 ft deep. The top of the inversion was near 2900 ft with a maximum temp of 26 C.
High confidence in VFR TAFs for KWJF, KPMD, KPRB, KBUR, & KVNY.
Moderate confidence in remaining TAFs. Timing of change groups may be off +/- 2 hours. CIG height accuracy +/- 300 ft of fcst. Minimum VSBYs may be off by 1SM or 2SM.
KLAX, Moderate confidence in TAF. Arrival and clearing times of IFR CIGs 008 (+/- 200ft) may be off by 2 hrs. No significant east wind component expected.
KBUR, High confidence in VFR TAF. No wind issues expected.
01/1244 PM.
Generally quiet conditions expected across the coastal waters for the forseeable future. Localized Small Craft Advisory (SCA) gusts near 21 kts may occur each afternoon and evening near Point Conception, off the coast of Point Dume, and across the San Pedro Channel.
01/1245 PM.
While we will get a break from the coastal flooding concerns for the rest of the week, another hurricane swell (from Rachel) will likely bring a larger-than-Polo south swell to southern California for the early to middle part of next week. Thankfully tides at that time will not be extreme, but they should be around 6.5 feet which is high enough to cause some concern, but it all depends on how big the surf ends up. Stay tuned for future updates.
Ca, Extreme Heat Warning in effect from 10 AM Friday to 8 PM PDT Thursday for zones 38-87-88-349>358-362-366>375-548-550. (See LAXNPWLOX). Heat Advisory in effect from 10 AM Saturday to 8 PM PDT Sunday for zones 341>345-347-348. (See LAXNPWLOX). PZ, NONE.
