23/1239 PM.
A shallower marine layer is expected over the next few days. Warm weather will peak on Wednesday and continue into Thursday. A push of moisture today will bring a low chance of a shower or an isolated storm from Ventura County eastward. This moisture will linger into Wednesday morning. A cooling trend with temperatures below normal is expected Friday into the weekend.
(Tue-Fri), 23/912 PM.
***UPDATE***
Scattered and elevated convective cells moved across eastern and northern parts of Los Angles County this afternoon and evening but very little rain was recorded at the surface. Most precipitation likely fell as virga. Very small (5%) chance of showers will continue into Wednesay morning as the moisture lingers in the area. There also remains a non-zero chance of fire starts from dry lightning with storms but the period with the highest chances of convection has already past.
***From Previous Discussion***
A 592 dm ridge is currently situated over Socal. This ridging is expected through Wednesday before breaking down to zonal flow on Thursday with significant cooling by Friday.
Heat advisories are in effect through Thursday evening across LA County. Temperatures are expected to be warmest Tuesday (Today) and Wednesday. Feels-like temps will be higher due to humidity. Refer to NPWLOX for more details.
Onshore flow will strengthen to the north through Thursday and to the east through Saturday. This will result in gusty SW winds across the interior - strongest across the Antelope Valley/ft hills and portions of LA county mtns. Approaching advisory levels Thursday into Friday. Sundowner potential increases on Friday, with likely advisory level winds especially on Saturday.
With increasing onshore flow, decreasing 500 mb heights, and increasing potential for Catalina Eddy (throughout the week) this will result in the continuation of marine layer stratus across the coasts and valleys.
(Sat-Tue), 23/120 PM.
An upper trough will strengthen and dive into the Great Basin through the weekend. As a result, cyclonic flow will develop over the region. Moderate to strong onshore flow to the east is expected. A bit weaker to the north. ECWMF guidance suggest a short-lived (Saturday & Sunday) reduction in onshore flow to the north followed by returning moderate onshore push. The general pattern is expected to persist thru the end of the forecast period.
Cooling trend is expected through Saturday or Sunday depending on location. Most pronounced on Saturday (5 to 10 degrees) especially across interior areas away from marine layer influence. Temperatures are likely to remain fairly similar thereafter thru Tuesday. June Gloom conditions are expected across the coasts and many of the valleys.
Gusty SW-W winds near advisory levels are likely Saturday and possible Sunday across the Antelope Valley and I-5 Corridor (NW-W). Winds will remain gusty but will decrease some Monday and Tuesday. But especially across the I-5 corridor as the LAX-BFL gradient increases by a few millibars. As mentioned in the short-term, Sundowners will peak on Saturday (advisory likely). Advisory level winds could linger into Sunday. Sundowners will continue through mid-week but for now look mostly below advisory levels. These winds will be focused across western Santa Ynez range.
24/0228z.
At 2117Z at KLAX, the marine layer was 700 feet deep. The top of the inversion was 2900 feet with a temperature of 22 C.
High confidence in TAFs for KPMD & KWJF.
Moderate to low confidence in the remainder of TAFs. Timing of CIG/VSBY restrictions may be delayed by up to 2 hours and cig hgt by +/- 200 ft. Low confidence in cigs reaching KBUR and KVNY, there is a 40% chance VFR conditions persist.
KLAX, Moderate confidence in TAF. Timing of flight category changes could be +/- 2 hours of current forecasts. No significant east wind component is expected.
KBUR, Moderate confidence in TAF. There is a 40% chance of VFR CIGs overnight through 16Z.
23/916 PM.
High confidence in winds and seas remaining below Small Craft Advisory (SCA) levels through Wednesday. Local gusts could reach 21 kts near Point Conception and across the western Santa Barbara Channel Wednesday evening. Chances for SCA criteria gusts increase Thursday evening. Probabilities increase Thursday evening into Friday morning to 30-60% for PZZ670/673. Chances expand and increase Friday afternoon to the inner waters PZZ645/650 and outer waters PZZ676. SCA conditions are possible through the weekend as a trough continues to move over the region.
Ca, Heat Advisory remains in effect until 9 PM PDT Thursday for zones 88-368-372-373-379-380-548. (See LAXNPWLOX). PZ, NONE.
