textproduct: Los Angeles

SYNOPSIS

23/259 AM.

Above normal temperatures will continue. Patchy night through morning low clouds and fog will be confined to coastal areas, mainly north of Point Conception. Additional warming is expected next week with periods of extreme heat in some areas, especially Tuesday through Friday.

LONG TERM (WED-SAT)

23/300 AM.

The only real question for the Wed through Fri forecast is: will it be very hot or extremely hot. This forceast problem is driven by a wide range of possibilities with the sfc gradients. The EC is show a fairly strong offshore push which would bring near record very dangerous heat to the area. The GFS keeps the E/W gradient onshore but even it has some offshore flow forecast from the north (just much less than the EC does). The upper high moves a little to the west but hgts really do not change much and should remain around 594 dam through the period.

Almost all of the vlys, lower mtn elevations and far interior will have temps between 100 and 110 degrees during this period. If the EC verifies Vly temps could end up 2 to 3 degrees warmer than the current forecast. The interior cst sections (such as DTLA) have a 15 percent chc of high temps of 100 to 103 degrees. The Central Coast will not be immune from the heat this time around. Offshore trends will lead to an 8 to 12 degree warm up on Wednesday leading to max temps in the upper 80s to mid 90s - there is a 10-20 percent chc that SLO could see 100 degrees.

In addition to the daytime highs overnight lows will be 8 to 12 degrees above normal and this will greatly exacerbate the heat risk as there will be no time for people's body to release the heat stress.

It is very likely that almost the entire forecast area will be blanketed by some combination of heat advisories and Extreme Heat Warnings starting Wednesday.

One additional local concern will be very hot sundowners across southern SBA county. A decent N to S gradient will set up over the county each evening and gusty north canyon winds will develop. These hot winds could drive max temps into the 100-105 degree range and could also keep temperatures in the 80s until almost dawn.

Some cooling is forecast on Saturday, but in the past these heat waves have held on a little longer than forecast.

AVIATION

23/0959Z.

At 0822Z at KLAX, the marine layer was 900 feet deep. The top of the inversion was at 2100 feet with a temperature of 30 C.

High confidence in VFR TAFs for KPRB, KSBA, KPMD, KWJF, KBUR, KVNY, KOXR, KCMA, & KSMO.

There is a 10% chc of LIFR/IFR CIGs at KLAX, KLGB, KSBP between 23/10Z-16Z.

KLAX...Fair confidence in CAVU TAF with only a 10% chance of LIFR/IFR CIGs 11Z-16Z. No significant east wind component is expected.

KBUR...High confidence in CAVU TAF.

MARINE

23/300 AM.

Moderate to high confidence in Small Craft Advisory (SCA) level winds (20-30 knots) across the Outer Waters at least through Monday night, most prevalent south and west of Point Sal. This may need to be extended through mid week and expanded to all waters again later in the week. SCA winds gusts are also expected across the nearshore waters along the Central Coast this afternoon and evening, then there is a moderate chance for more widespread wind gusts reaching 25 knots during the afternoon and evening hours starting Tuesday and likely continuing through the week.

Gusts of 20-25 knots should reach the western half of the Santa Barbara Channel each afternoon/evening starting Monday and continuing through the week. Moderate chances of SCA level winds reaching the eastern portion of the channel by mid-week. Otherwise widespread SCA conds are not likely for the inner waters south of Point Conception.

LOX WATCHES/WARNINGS/ADVISORIES

CA...Heat Advisory in effect from 10 AM this morning to 10 AM PDT Tuesday for zones 38-87-88-349>358-362-366>376-378>380-548. (See LAXNPWLOX). Extreme Heat Watch in effect from Tuesday morning through Friday evening for zones 38-87-88-349>358-362-366>376-378>383-548. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 11 PM PDT this evening for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect until 4 AM PDT Tuesday for zones 673-676. (See LAXMWWLOX).