Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
957 FXUS66 KLOX 250508 AFDLOX Area Forecast Discussion...UPDATED National Weather Service Los Angeles/Oxnard CA 1008 PM PDT Mon Jun 24 2024 .SYNOPSIS...24/919 PM. Remnant sub-tropical moisture will remain over the area into Tuesday. A gradual cooling trend will continue through midweek as high pressure weakens over the area and onshore flow strengthens. Night through morning low clouds and fog could return to the coastal areas as soon as Tuesday morning, but there is a better chance for Wednesday and Thursday. Temperatures could potentially rebound over the upcoming weekend and into early next week as high pressure aloft builds back into the region. && .SHORT TERM (MON-THU)...24/1007 PM. An upper-level ridge of high pressure is currently centered over southern New Mexico this evening. Above normal temperatures will continue across the region over the coming days as enough of the high`s influence will remain despite strengthening onshore flow. Remnant sub-tropical moisture continues to stream over the region this evening. A few showers remain over areas north of Point Conception this evening from a vorticity maximum that moved over the region. Some clouds are billowing out ahead another vorticity maximum off the coast of Baja California, but the latest models suggest convective parameters be not as favorable for development. A non-zero chance of showers and thunderstorms will continue into Tuesday evening as the moisture will remain in place. The low cloud field is marginally in place this evening as the convective cloudiness plays tricks with the marine layer deck. The latest NAM-WRF solutions continue to suggest an eddy circulation developing through Tuesday morning. Night through morning low clouds and fog have been added to the forecast, but low-to- moderate confidence exists at this time. With onshore flow and low clouds returning, a cooling trend should continue into midweek. Outside of the marine layer across the interior portions of the area, a hot air mass will remain in place into Tuesday. Heat advisories have been extended across the interior portion of San Luis Obispo and Santa Barbara Counties into Tuesday evening, while an excessive heat warning remains in effect for the Antelope Valley and adjacent eastern foothills. ***From Previous Discussion*** Excessive heat products with moderate to high heat impacts continue through this evening for portions of the interior, except through Tuesday evening for the Antelope Valley. We have high confidence that cooling trends initiated today across the interior will continue through Wednesday, decreasing heat impact to much lower levels than weve experienced now for many areas for at least several days. As such, we do not anticipate extending any of the heat products. The moisture associated with the mid cloud deck continues to support a 5-15 percent chance (highest across the interior Mountains and deserts) of a thunderstorm across the region today with afternoon cumulus and a shower or two already showing up along the high terrain. Dangerous cloud-to-ground lightning and damaging wind would be the main concerns should a stronger thunderstorm or two form with climatologically favored areas for this being the eastern San Gabriel mountains into the Antelope Valley and Ventura mountains west to the Santa Barbara mountains (excluding the Santa Ynez Range). Generally weak flow aloft would likely support slow storm movement towards the north or northeast around 10 mph with anchoring or back building along the high terrain possible. Any stalled thunderstorms may also produce localized flash flooding. Generally light onshore winds today will likely become stronger with a west to northwest orientation Wednesday and Thursday, potentially approaching advisory levels for southwest Santa Barbara County and the mountains near the I-5 corridor. Low confidence in low cloud and fog forecast as the marine layer may struggle to reform as mid level moisture may stick around until Tuesday or so. Sufficient moisture sticks around until at least Tuesday afternoon to warrant a 5-10 percent chance of a shower or thunderstorm across southwest California and the adjacent waters. .LONG TERM (FRI-MON)...24/208 PM. Low confidence in the extended period. There is now a 60-70 percent chance that weak troughing will remain in place through the weekend with building heat early next week. That does leave a 20-30 percent chance that heat builds as early as this weekend. If the higher heat scenario plays out, there may be a monsoon push into at least Los Angeles County early next week. Breezy west to northwest winds will continue, peaking each afternoon and evening, potentially nearing advisory levels for southwest Santa Barbara County at times. && .AVIATION...25/0223Z. At 23Z over KLAX, the marine layer depth was 800 feet deep at KLAX. The top of the inversion was near 2400 feet with a temperature near 27 degrees Celsius. Moderate confidence in the current forecast. VFR conditions are expected through the period, except for a moderate-to-high chance of LIFR to IFR conditions between 08Z and 16Z for coastal terminals. There is a very slight to slight chance of showers and thunderstorms, highest for terminals north of Point Conception. KLAX...There is a less than 10 percent chance of thunderstorms through 12Z. There is a 60 percent chance of IFR conditions as early as 09Z, or as late as 16Z. Otherwise, VFR conditions are expected. KBUR...There is a less than 10 percent chance of thunderstorms through 12Z. Otherwise, VFR conditions are expected. && .MARINE...24/950 PM. Dense fog with visibilities under one mile will remain a concern, and while the coverage and shrunk a lot, expect some random patches tonight into Tuesday. There is a 30 percent chance of Small Craft Advisory (SCA) level wind gusts Tuesday evening/night for the Outer Waters (offshore waters of the Central Coast to San Nicolas Island). Northwest winds will increase Wednesday afternoon through Thursday night. High confidence in SCA level winds and steep seas for the Outer Waters, with a 20 percent chance of reaching low-end Gale Force. 50 percent chance for SCA winds and seas for the nearshore Central Coast waters, and a 20 percent chance for the western Santa Barbara Channel. Winds start to decrease to SCA levels for Friday into the weekend. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Heat Advisory in effect until 8 PM PDT Tuesday for zones 38-344-345-353. (See LAXNPWLOX). Excessive Heat Warning remains in effect until 8 PM PDT Tuesday for zones 382-383. (See LAXNPWLOX). PZ...NONE. && $$ PUBLIC...Hall/Munroe AVIATION...Hall MARINE...Phillips/RK SYNOPSIS...Hall weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox