textproduct: Los Angeles

SYNOPSIS

09/225 PM.

Moderate heat impacts will continue into next week, though there will be slight cooling over the weekend. Monsoonal showers and thunderstorms will be possible starting Sunday. Temperatures will rise again on Tuesday and my reach Major Heat Risk levels, with the monsoonal moisture adding to the discomfort from the heat.

LONG TERM (MON-THU)

09/311 PM.

High pressure aloft will encompass much of the western half of the CONUS to start the extended periods, centered across the intermountain west. This will result in southeasterly flow across the local area, helping to steer in some monsoonal moisture around the periphery of this high over the course of next week. As this ridge expands to the southwest over the middle of next week, expect heights aloft to rise and for temperatures to climb further, with a potential for extreme heat across parts of the local area. With all this in mind, there have been no changes to the previous headlines with a heat advisory in effect through Tuesday (for moderate heat - a level 2 of 4) and an extreme heat watch for next Tuesday through Thursday when temperatures are expected to warm further.

Regarding the monsoonal moisture, global models paint a fairly consistent picture that there should be some showers and thunderstorms across at least parts of the local area for several days. While the exact location and timing of convective activity several days out is uncertain, the most favored ares will be across the interior mountains and deserts each day from the late afternoon through evening hours, highly dependent on any embedded disturbances that could help force more widespread activity. At this time, we are thinking a 10-20% chance of a storm each day should cover this potential, with additional refinements as we get closer in time/certainty.

Otherwise, the prolonged period of warm weather rounds out the rest of the story, with slightly above normal temperatures and noticeably more humid conditions both Monday and Tuesday, followed by a bump in temps over the middle to latter portion of the week that is currently covered by the aforementioned excessive heat watch.

AVIATION

10/0034Z.

At 0001Z at KLAX, the marine layer was 1100 ft deep. The top of the inversion was around 5100 ft deep with a temperature of 27 C.

High confidence in TAFs for the desert sites of LA County, with moderate to high confidence in KPRB, KSBA, KBUR and KVNY with a 30 percent chance of low clouds moving in overnight. LIFR conds possible at KPRB and KSBA, with IFR to MVFR for the LA County valley sites. Timing of CIGs arrival could differ by up to 2 hours from forecast times.

Otherwise moderate confidence the remaining coastal sites, with LIFR conds likely north of Point Conception, IFR for Ventura and LA coastal sites. There is a 30% chance of MVFR conds for the LA coastal sites.

KLAX...Moderate confidence in the 00Z TAF. There is a 40 percent chc of no cigs. Moderate confidence that MVFR/IFR conds will arrive between 0300Z and 0600Z. Otherwise, timing may differ by +/- 2 hrs from TAF times. High confidence that any east wind component will be AOB 6kt.

KBUR...MOderate to high confidence in TAF. with a 30% chance of IFR to MVFR CIGS between 10Z and 16Z.

MARINE

09/152 PM.

For the outer waters, Small Craft Advisory (SCA) level NW winds are expected to continue through at least Saturday morning. Large 10-12 ft seas will subside late Friday night.

SCA level NW-W winds, are expected to continue for the waters for the waters around Point Conception through tonight before starting to diminish late tonight into Saturday morning. Going into midday Saturday, SCA conditions are expected to come to an end for these waters and should remain well below for the weekend.

For the inner waters south of Point Conception, conditions are expected to remain below SCA levels.

BEACHES

09/152 PM.

A south to southwest swell will continue to affect the coastal waters through next week. With the swell, the potential for larger surf and greater risk for rip currents will continue. High tides are expected to increase this weekend going into next week with Monday expected to be the highest tide of 7.0 to 7.6 ft above MLLW. There is the potential for some minor coastal flooding next week with the high tides and south swell. One thing that will need to be watched into next week will be the potential of a greater south to southwest swell from potential tropical development.

Thunderstorms still continue to be possible starting Sunday and going through next week with a 10-20% chance.

LOX WATCHES/WARNINGS/ADVISORIES

CA...Heat Advisory remains in effect until 10 AM PDT Tuesday for zones 38-88-343>345-353-368-372-373-375>380-548. (See LAXNPWLOX). Extreme Heat Watch in effect from Tuesday morning through Thursday evening for zones 38-88-341>345-347>358-362-366>376-378>383-548. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 5 AM PDT Friday for zones 645-676. (See LAXMWWLOX). Small Craft Advisory in effect until 5 PM PDT Saturday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect until 5 AM PDT Saturday for zone 673. (See LAXMWWLOX).