28/123 PM.
Beach impacts from Tropical Cyclones well south of the region are expected through Tuesday in the form of high surf, beach erosion, and possible coastal flooding. Warming temperatures are expected Tuesday with periods of northeast winds in the mountains. A major heat wave is likely this weekend into next week with dangerously hot temperatures and periods of Santa Ana winds.
(Mon-Thu), 28/843 PM.
***UPDATE***
Scattered showers and thunderstorms occurred across the western San Gabriel Mountains and the Antelope Valley this afternoon and evening, rain totals ranged from a trace to up to around 0.5 inches. North winds remain on track for tonight into tomorrow morning for the Santa Barbara and Ventura County mountains as well as the I5 corridor, gusts of 25 to 45 mph are common currently.
***From Previous Discussion***
An upper low continues to move through the state today and expected to be into AZ by Wednesday. As the low progresses through the area, northerly winds will increase across the Santa Barbara and Ventura County mountains as well as the I5 corridor region with gusts to around 45 mph tonight into Tuesday morning.
On Tuesday increasing surface pressures over the Great Basin following the upper low will usher in the first little Santa Ana of the season. This will be a low end Santa Ana with northeast winds mostly confined to the mountains and mostly below 35 mph. But the shift to northeast winds aloft will cause humidities to drop considerably across the mountains and should even be noticeable at lower elevations. Temperatures will rocket up at least 5 degrees at the coast and as much as 10 or more degrees elsewhere.
A slight cool down is expected Wednesday and Thursday as gradients turn back to lightly onshore. It will still be 2-5 degrees above normal but with the return to onshore flow it's likely humidities, especially closer to the coast, will increase by 15-30 percent.
(Fri-Mon), 28/222 PM.
Most of the models now are in agreement with a potentially dangerous heat wave this weekend and all of next week due to high pressure aloft and increasing offshore gradients. Warming will begin to ramp up Friday with around 3 degrees of warming each day through next Monday. Gradients will be a factor, though even without the offshore gradients forecast by the models this would still be an impressive heat wave. But if the medium or high end gradient solutions pan out this could be a very dangerous and week long heat wave with warmer valley highs of 105-110, Downtown LA and other inland coastal zones 100-104, and coastal areas 85-98. PW's are expected to remain under an inch through next week, but due to the continued much above normal SST's, humidities at lower elevations will remain much higher than we are used to.
29/0409z.
At 22Z at KLAX, there was no marine layer or inversion.
High confidence in VFR TAFs for KPRB, KWJF, KPMD, KSBA, and KCMA. Moderate confidence elsewhere with a 10-20 of brief IFR or lower cigs/vsbys, especially for KLAX, KLGB, and KSMO.
KLAX, Moderate confidence in TAF. There is a 10-20 percent chance BKN008 conds 08Z-16Z. High confidence in no significant east wind component.
KBUR, High confidence in VFR TAF.
28/1012 PM.
High confidence in Small Craft Advisory (SCA) winds and steep seas affecting the outer waters through late least Tuesday night. Local Gale Force gusts will be possible at times, especially Tuesday afternoon and evening for the outer waters south of Point Conception and north of Point Sal. Nearshore waters along the Central coast will see SCA winds and steep seas Tuesday afternoon and evening.
For the inner waters south of Point Conception, SCA winds are expected across much of the Santa Barbara Channel and portions of the inner waters adjacent to Los Angeles and Orange Counties Tuesday.
Southerly swell from Polo (SSE) will continue to affect the region through Tuesday. These swells will create larger waves and surf nearshore, which could impact some south exposed harbor entrances.
Conditions are likely to improve to below SCA levels Wednesday into next weekend, except for occasional northwest SCA winds near Point Conception in the afternoon/evening hours.
28/1006 PM.
Southerly swell from Hurricane Polo will continue to affect our coastline into Tuesday. This swell timing will line up with very high tides though Tuesday morning. Some south- facing shores are more vulnerable because of the lingering erosion effects from Hurricane Marie earlier this month.
Surf heights across Los Angeles and Ventura Counties are likely to peak around 4-7 feet through Tuesday, while the Santa Barbara south coast should see surf in the 3-5 foot range. High tides are peaking around 7 feet (MLLW) in the late morning hours - which is higher by almost a foot over astronomical tides due to ongoing effects of El Nino.
While this swell is slightly smaller than the swell from Marie, there is still significant concern of Coastal Flooding over vulnerable south-facing beaches. The areas of most concern include Avalon, Long Beach, Malibu, and to a lesser extent Santa Barbara.
South-facing beaches should plan for shallow flooding of seawater over low lying beach walkways, parking lots, and roads as well as potential for significant beach erosion. Very localized damage to structures is possible in the most vulnerable areas. Minor tidal overflow may affect west facing beaches due to very high tides.
Beach Hazards Statements (BHS) are in effect for Santa Barbara south coast through Wednesday. A Coastal Flood Advisory and High Surf Advisory are in effect for LA and Ventura through Tuesday afternoon. A BHS may need to be issued for the LA and Ventura coasts for Tuesday afternoon through Wednesday (lining up with Santa Barbara) due to the very high tides.
The East Pacific Hurricane Season is forecast to remain active, with with additional southerly swells and surf/coastal flooding impacts possible again next week.
Ca, Coastal Flood Advisory in effect until 5 PM PDT Tuesday for zones 87-354-362-366. (See LAXCFWLOX). High Surf Advisory in effect until 5 PM PDT Tuesday for zones 87-354-362-366. (See LAXCFWLOX). Wind Advisory in effect until 6 AM PDT Tuesday for zones 349>353-376>378. (See LAXNPWLOX). Beach Hazards Statement in effect through Wednesday afternoon for zones 349-350. (See LAXCFWLOX). PZ, Small Craft Advisory in effect until 11 PM PDT this evening for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect from 2 PM to 11 PM PDT Tuesday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 1 AM PDT Tuesday for zones 650-655. (See LAXMWWLOX). Small Craft Advisory in effect from 2 PM Tuesday to 1 AM PDT Wednesday for zones 650-655. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Wednesday for zones 670-673-676. (See LAXMWWLOX).
