textproduct: Los Angeles

SYNOPSIS

10/217 AM.

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 may reach Major Heat Risk levels, with the monsoonal moisture adding to the discomfort from the heat.

LONG TERM (MON-THU)

10/217 AM.

The upper high will migrate to South Dakota on Monday and then sit there for a while. It will also strengthen and push hgts over CA up from 590 dam to 594 dam. The onshore flow to the east will increase to mdt-stg on Monday and will no change much through the rest of the week. The N/S gradient is a much trickier call with many different solutions possible ranging from weak onshore to mdt offshore. Pinning down this value will be the key to getting next weeks forecast correct.

The monsoon will continue on Monday with partly to mostly cloudy skies and a 10 to 20 percent chc of showers and isold TSTMs over the mtns. The increase in onshore flow will likely bring another round of morning low clouds although there is a chc that the advection of monsoon moisture may disrupt the marine inversion. Max temps will not change much from Sunday's values and will remain above normal.

The long range mdl consensus is that the monsoon will stop on Tuesday and skies will become mostly sunny. The marine layer and temp forecast begins to get problematic due to the uncertainty in the N/S pressure gradient. Right now it looks like the best bet is for continued onshore flow which means a good chc of morning stratus and only a degree or two of warming due to the increase in sunshine.

Rising hgts and a better chc of weak onshore or even offshore flow in the N/S direction will bring 3 to 6 degrees of warming to most areas. Vly temps will likely range from 95 to 105. A heat watch is in effect to cover the good possibility of these temps.

The mdl consensus points to an increase in onshore flow to the normal next Thursday perhaps a substantial increase. This will likely increase the morning clouds and bring 3 to 6 degrees of cooling to the area. Even with this cooling max temps will remain above normal. The is also a chc of a return of the monsoon with a 10 to 20 percent chc of showers/TSTMs developing over the mtns.

AVIATION

10/1031Z.

At 0833Z at KLAX, the marine layer was 1200 ft deep. The top of the inversion was around 4500 ft deep with a temperature of 26 C.

High confidence in TAFs for KPMD and KWJF.

Low confidence in TAF for KPRB with a 40 percent chc of LIFR conds 12Z-16Z.

Moderate confidence in the remaining TAFs. Timing of flgt cat changes could be off by +/- 90 min and cig hgt off by +/- 300 ft.

KLAX...Moderate confidence in TAF. VFR conds could arrive anytime between 17Z and 19Z. High confidence that any east wind component will be AOB 6kt.

KBUR...Moderate confidence in TAF. There is a 20 percent chc of OVC004 conds through 15Z. VFR conds could arrive anytime between 1600Z and 1730Z.

MARINE

10/217 AM.

For the outer waters, Small Craft Advisory (SCA) level NW winds are expected to continue subside from south to north through Saturday. Across the far northern outer waters there will be gusts up to 30 knots. Large short period NW seas 8 to 10 feet at 8 seconds will gradually diminish through early next week.

For the nearshore waters along the Central Coast, SCA winds are this afternoon and evening. Otherwise, mainly light winds are then expected through Tuesday morning, then increasing Tuesday afternoon and evening.

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

BEACHES

09/756 PM.

A south to southwest swell will continue to affect the coastal waters through next week. With this longer period swell, the potential for larger surf and a 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 from 3 PM this afternoon to 9 PM PDT this evening for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 5 PM PDT Saturday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Saturday for zone 673. (See LAXMWWLOX).