textproduct: Los Angeles

SYNOPSIS

12/906 AM.

Temperatures will increase each day into mid-week, resulting in widespread Moderate to Major HeatRisk Tuesday through Thursday. Monsoonal moisture moving into the area will add to the discomfort, bringing shower and thunderstorm potential each day, highest in the mountains.

LONG TERM (WED-SAT)

12/319 AM.

Heat will be the primary hazard next week, and an Extreme Heat Watch is in effect Tuesday through Thursday for all areas except the beaches along the Central Coast. Widespread moderate to major HeatRisk is anticipated for the region. Over the next couple days, some locations are likely to to be converted to Heat Advisories, while others may become Extreme Heat Warnings. High temperatures in the warmest valleys and deserts have the potential to be between 95 to 110 degrees. Even the beaches and coastal plains may see highs between 85 and 95 degrees. Temperatures are favored to trend down Friday into the weekend, though there is a fairly large range of outcomes as to how much. The most likely scenario would bring temperatures back down to near normal for mid-July by the weekend. However, the humidity is poised to stay through the extended period (and beyond), and this would still present Minor to Moderate HeatRisk across much of the region, especially away from the coasts. Ensembles suggest PWATs hover around 1.5 inches during the period and even into the next week, so muggy days are in the near and long term future here is Southwest California.

The periphery of the high pressure centered over the Plains will nose into the Southern California region starting Wednesday. This will alter the flow pattern to be more southwesterly compared to the southeasterly flow expected earlier in the week. This will likely cut off the moisture source for the region, thus chances of thunderstorms and showers will likely drop to around 10 percent across the region for Wednesday and Thursday. However, starting Friday, other influx of monsoonal moisture from the southeast will be possible, and thunderstorm chances will likely bump back up to around 20 percent. The thunderstorm forecast will be complex with generally low confidence for any particular location, as storm development will be highly dependent on mesoscale features and even potential outflows form storms well outside of our forecast area. The greatest chances will be during the afternoon and evening hours across the mountains of Los Angeles and Ventura Counties.

Moderate Sundowner winds for southwestern Santa Barbara County and northwest winds over the interior are expected Wednesday night and potentially Thursday night (although weaker Thursday). Otherwise winds will trend slightly more onshore Thursday into the weekend.

AVIATION

12/1742Z.

At 1721Z at KLAX, the marine layer depth was was 1700 ft. The top of the inversion was at 3200 ft with a max temperature of 24 C.

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

Moderate confidence in the remaining TAFs. Mid and high clouds will likely continue to disrupt the marine layer cloud formation through tonight, and any cigs that do form are likely to be patchy and scatter and reform frequently later tonight into Mon morning.

KLAX...Moderate confidence in TAF. There is a 40% chance of no MVFR cigs forming late tonight into Mon morning, and if any do form they may bounce between BKN015 and BKN250. High confidence that any east wind component will be below 6kt.

KBUR...Generally high confidence in TAF. There is a 10%-20% chance of brief OVC008-015 cigs 12Z-16Z Mon.

MARINE

12/826 AM.

For the outer waters, winds and seas are largely expected to be below Small Craft Advisory (SCA) levels through Tuesday, then there is a 50%-60% chance of SCA winds and seas developing Tuesday night through Thursday night.

For the nearshore waters along the Central Coast, mainly light winds are expected through Tuesday, but winds will begin to increase on Tuesday, likely reaching SCA levels Wednesday afternoon through Thursday night. Short period seas may also reach SCA levels.

For the inner waters south of Point Conception, conds are expected to remain below SCA levels through the forecast period, except for a 50% chance of SCA wind gusts over the western portions of the Santa Barbara Channel Wednesday and Wednesday night.

BEACHES

12/830 AM.

A south to southwest swell will continue to affect the coastal waters through this week. With this longer period swell, the potential for larger surf and a greater risk for rip currents will continue.

Evening high tides are expected to increase this week with Monday expected to be the highest tide of 7.1 to 7.7 ft above MLLW. There is the potential for some minor coastal flooding this week with the evening high tides and south swell. One thing that will need to be watched late this week into the weekend will be the potential of a greater south to southwest swell from potential tropical cyclone over the eastern Pacific.

Thunderstorms will be possible along the beaches today into Monday (10-20% chance). For more information, please refer to the Beach Hazard Statement.

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). Beach Hazards Statement in effect through Wednesday evening for zones 340-346-349-350-354-362-366. (See LAXCFWLOX). PZ...NONE.