textproduct: Los Angeles

SYNOPSIS

01/210 PM.

Hot conditions are expected well into next week, generally hottest through Sunday, especially closer to the coast. There is a high risk of heat-related illness during this time. Dense fog will affect some coastal areas.

LONG TERM (WED-SAT)

01/127 PM.

High pressure starts to build again over the southwest Wednesday through the end of the week, just not as strongly as this weekend. High temperatures will remain higher than normal with elevated and extended concerns of heat illnesses persisting. Can see a smattering of Heat Advisories and Warnings for the middle to end of the week, especially for interior areas, but that is not a certainty as we get deeper and deeper into typically hot season. The position of the high for most ensemble projections also turns the flow aloft back to southeasterly, which means there will be a several day window for monsoonal moisture to start pushing back up. There is a range in the projections as to how much moisture, which is unsurprising this far out. With that said, all signs are pointing towards a warmer and muggier close to the week.

AVIATION

01/2352Z.

At 2317Z at KLAX, there was no marine layer. The top of the inversion was near 3500 feet with a temp of 30 degrees Celsius.

High confidence in VFR conds for KPRB, KBUR, KVNY, KPMD and KWJF.

Low confidence in TAFs for KSBP, KSMX and KSBA. Expecting conds similar to last night with a 20% chance of VLIFR conds with FG for the Central Coast sites. The timing of flight category changes may differ by +/- 2 hours from TAF times.

Low to moderate confidence in KOXR, KCMA and the LA Coastal sites. IFR conds are expected with a 30% chance of MVFR conds for the LA coastal sites. Flight categories could differ from TAF times by at least +/- 2 hours, and CIGs could form and dissipate at times between around 06Z to 15Z.

KLAX...Low to moderate confidence in the 00Z TAF. The timing of flight cat changes may be off +/- 2 hours from TAF, and there is a 20% chance of no CIG restrictions, and a 20-30% chance of MVFR conds. No significant east wind component expected.

KBUR...High confidence in the 00Z TAF with VFR conds expected.

MARINE

01/809 PM.

For the western portion of the Santa Barbara Channel and the inner waters north of Point Sal, there is a 30-40% chance of SCA winds during the afternoon and evening hours through this weekend. Otherwise conditions are expected to remain below SCA levels.

For the Outer Waters, Small Craft Advisory (SCA) winds and seas will continue through Sunday night before beginning to subside early this coming week. Winds will generally peak at around 30 knots, strongest during the evening hours.

Seas of 7-10 feet will impact the outer waters through this weekend, due to a combination of long-period southerly swell from a distant tropical cyclone and shorter- period northwesterly swell/wind- waves caused by the prevalent NW winds. As a result, steep, hazardous seas will be common, especially over the outer waters, extending to nearshore waters off the Central Coast. Seas will begin to subside as the winds weaken late Sunday night into early next week.

Dense fog will affect some of the coastal waters each night and morning going forward.

BEACHES

01/811 PM.

The surf will diminish further on Sunday, but moderate to locally strong rip currents will still be common on exposed south to southwest facing beaches.

Continue to use extra caution if you are at the beach, and be sure to ask lifeguards if and where it is safe to swim.

FIRE WEATHER

01/345 PM.

Today through next Friday, widespread elevated to brief critical conditions will be common across the interior valleys, mountains, and deserts due to hot, dry, and breezy onshore conditions with an increased risk for large plume dominated fire behavior and rapid fire growth due to deep mixing heights. For today, mixing heights of 12,000 to 16,000 feet are expected across the interior, and 10,000 to 14,000 feet on Sunday, with continued deep mixing heights most of next week. If any fire ignitions occur across the interior, these deeper mixing heights will allow for large vertical plume growth, especially in the mountains and foothills, where Live Fuel moisture levels are approaching critical levels.

Other factors that will add to the fire weather risk across the interior today through next Friday, will be southwest to northwest winds 10 to 25 mph with gusts 20 to 35 mph, as well as widespread and long duration single digit humidities. As a result, expecting at least a few hours of wind/RH overlap to reach brief critical fire weather conditions across many interior areas each afternoon and early evening. A few isolated mountain and Antelope Valley foothill locations could reach 6+ hour Red Flag durations of wind/RH overlap this weekend. Since the necessary Red Flag duration of 6+ hours is expected to be isolated, no Red Flag Warning is expected to be issued through the weekend. In addition, there will be very poor to poor overnight humidity recoveries, especially in the mountains and foothills where some locations may continue to have humidities in the teens.

Confidence is growing for interior areas to remain hot and dry into next week, with the continuation of elevated to brief critical fire weather conditions. With slightly enhanced onshore winds each afternoon and evening overlapping with single digit humidities in the 5-10 percent range, there will be a 10-20 percent chance of Red Flag Warnings next week for interior San Luis Obispo county mountains/valleys as well as interior Santa Barbara county mountains/Cuyama Valley (where the driest air is expected to be focused).

LOX WATCHES/WARNINGS/ADVISORIES

CA...Extreme Heat Warning in effect until 8 PM PDT Sunday for zones 38-88-343>345-351>353-356>358-368>376-378-379-381>383-548. (See LAXNPWLOX). Heat Advisory in effect until 8 PM PDT Sunday for zones 342-348>350-354-355-362-366-367-377-380. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 3 AM PDT Monday for zones 670-673-676. (See LAXMWWLOX).