Area Forecast Discussion

SYNOPSIS

11/117 PM.

Marine layer stratus and fog will expand over the coasts and sprawl further inland Friday through the weekend. A subtle cooling trend will persist for most locations through Sunday. Despite the cooling, most high temperatures will remain above normal with the exception of the coasts, which will see temperatures near to slightly below normal.

SHORT TERM (TDY-SUN)

11/1240 PM.

Low clouds continue to surge northward over the waters west of the Central Coast while simultaneously receding off of the Southern Coast. Those near the beaches should enjoy the sunshine today because fog and stratus may be slower to clear out Friday through the weekend. Persistent onshore flow will allow the marine layer to sprawl further inland overnight and stick around longer during the day.

Temperatures today are running 5 to 15 degrees cooler than this time yesterday for Central Coast beaches and valleys thanks to the influx of marine air. Temperatures have cooled along the Southern Coast too, albeit subtly, with readings down by 2 to 5 degrees today compared to yesterday. Interior valleys have yet to see relief from the heat with most readings trending around 5 degrees warmer than yesterday.

Most areas will see an additional 1 to 3 degrees of cooling Friday as the marine layer expands, then temperatures will level off Saturday. Despite the cooling trend, almost all high temperatures will remain above mid-June normals through the period with only the beaches seeing normal or slightly below normal temps. In general the coasts will see afternoon high temperatures in the 70s and low 80s, while the valleys will warm into the mid 80s to mid 90s.

In addition to cooling temperatures and expanding marine layer stratus, a weak area of low pressure circulating southwest of the region over the Pacific will direct some mid-level monsoonal moisture into Southern California Friday. As a result, precipitable water values are forecast to climb near 1 inch. Models continue to keep the bulk of the moisture and associated afternoon convection south of LA County in Orange and San Diego Counties. However, there is a small (10 percent) chance that enough moisture will creep upward to bring showers or thunderstorms to the San Gabriel Mountains.

LONG TERM (MON-THU)

11/108 PM.

Typical June gloom conditions will prevail through the period. Moderate onshore flow will persist, blanketing the coasts and many valleys with marine layer stratus and fog overnight and into each morning.

Fluctuations in temperatures will be minimal. Most areas will cool by a degree or two on Sunday, then temperatures will stay consistent into early next week. High temperatures will generally be near or even a degree or two below normal along the coasts and coastal valleys thanks to the marine influence. Meanwhile, mountains and interior valleys will sit 5 to 10 degrees above normal due to weak high pressure over the region.

AVIATION

11/2347Z.

At 2326Z at KLAX, the marine layer was 1100 ft deep. The top of the inversion was at 2000 ft with a maximum temperature of 24 C.

High confidence in VFR TAFs for KPRB, KPMD and KWJF.

Moderate confidence in remaining TAFs. Timing of CIG/VSBY restrictions may be off +/- 2 hours and flight minimums by one category.

KLAX...Moderate confidence in TAF. Arrival and clearing times of CIGs may be off +/- 2 hours. 35% chance CIGs lower to LIFR 003-004 from 12/06Z-12Z. No significant east wind component expected.

KBUR... Moderate confidence in TAF. No wind issues expected.

MARINE

11/132 PM.

Conditions are generally expected to remain below Small Craft Advisory (SCA) levels through early next week.

Local wind gusts could reach or exceed 21 kts near Pt Conception, Pt Dume, near the Channel Islands, western Santa Barbara Channel, and across the San Pedro Channel. Low chance of advisory through the weekend.

BEACHES

11/132 PM.

Another long period southerly swell (less energy) originated from the southern Hemisphere is expected to arrive on Saturday. Evening tides of near 7.5ft are predicted from Saturday through Tuesday. The combination of these two factors may result in minor to locally moderate coastal flooding for south exposed coasts. Even as tides lower, another southerly swell arrives which could extend concerns into Wednesday or Thursday. Stay tuned for updates.

LOX WATCHES / WARNINGS / ADVISORIES

CA...High Surf Advisory in effect until 8 PM PDT this evening for zones 87-362-366. (See LAXCFWLOX). Beach Hazards Statement in effect until 8 PM PDT this evening for zone 354. (See LAXCFWLOX). PZ...NONE.