textproduct: Los Angeles

SYNOPSIS

19/1208 AM.

Well below normal temperatures to continue through the weekend, with a deep marine layer and a few spits of drizzle, as well as gusty winds over the interior. A significant warming trend will start Monday or Tuesday and peak Wednesday and Thursday.

LONG TERM (MON-THU)

19/332 AM.

On Monday a change in the weather will commence. A ridge standing from an upper high near the intersection of AZ/NM/MEX will slowly push into Srn CA from the SE. Hgts will slowly rise to about 594 dam, which is about 8 dam higher than normal. Hgts of this value will squish the marine layer down to 1000 ft or less which will greatly reduce the amount of low clouds in the vlys. It will, however, strengthen the marine inversion which will make coastal clearing more difficult. Mdt to stg onshore flow will continue although there will be weaker onshore flow to the north in the morning. These onshore gradients and the strong capping inversion will bring plenty of low clouds to the csts and some lower vlys. The marine layer will moderate the cstl warming and only 1 or 2 degrees of warming is likely each day there. For the vlys and further inland areas, however, the absence of a marine layer and building hgts will allow for 3 to 6 locally 8 degrees of warming each day. By Tuesday triple digit heat is likely in the Antelope Vly while the vlys will warm into the upper 80s and lower 90s.

Wednesday will be the warmest day as the hgts peak. Vly temps will likely end up in the upper 80s to mid 90s. There is a 25 percent chc of much warmer temps due to a chc of the upper high moving westward combined with much weaker onshore flow. Because of this chc an excessive heat watch is in effect. This chc of heat warning will be continuously monitored over the next three days.

Thursday looks a little cooler as the upper high weakens.

AVIATION

19/0956Z.

At 0833Z at KLAX, the marine layer was 2500 ft deep. The top of the inversion was near 5000 ft with a temperature of 20 Celsius.

High confidence in KPMD & KWJF staying VFR with gusty southwest winds.

Moderate confidence in ceilings at all other airports. There is a 15 percent chc of IFR cigs at times. VFR transitions may be off by +/- 2 hours

KLAX...Moderate confidence in TAF. There is a 30 percent chc of 015 cigs through 17Z and a 15 percent chc of 008 cigs 11Z-16Z. VFR conds could arrive as early as 18Z or as late as 22Z. No significant east wind component expected.

KBUR...Moderate confidence in TAF. There is a 30 percent chc of cigs no hier than 015. There is a 15 percent chc of 008 cigs 11Z-16Z. VFR conds could arrive as early as 18Z or as late as 21Z.

MARINE

19/223 AM.

Fairly high confidence in winds and seas staying below Small Craft Advisory (SCA) criteria through Sunday, but typically gusty winds of 15 to 20 knots will form each afternoon and evening over many nearshore waters as well as around the Channel Islands.

LOX WATCHES/WARNINGS/ADVISORIES

CA...Extreme Heat Watch in effect from Tuesday morning through Thursday evening for zones 88-368-372-373-379-380-548. (See LAXNPWLOX). Wind Advisory remains in effect from 1 PM this afternoon to 10 PM PDT this evening for zones 381-383. (See LAXNPWLOX). PZ...NONE.