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
074 FXUS66 KLOX 071202 AFDLOX Area Forecast Discussion...UPDATED National Weather Service Los Angeles/Oxnard CA 502 AM PDT Fri Jun 7 2024 .SYNOPSIS...07/337 AM. Fairly widespread low clouds and nighttime fog will affect areas near the coast each day into next week, with areas of partial clearing during the afternoon. While temperatures will be a few to several degrees below normal close to the coast with onshore flow, temperatures will be warmer over interior sections. Precipitation is not expected over the region through at least the middle of next week. && .SHORT TERM (TDY-SUN)...07/308 AM. Upper level heights are expected to continue to fall gradually over the next few days, with a moisture-starved trough reaching the region by Sunday. However, the overall weather pattern will be quite similar through the weekend, and dropping daytime high temperatures will be the most notable difference day-to-day. For interior locations (i.e., deserts, mountains, and most valleys), temperatures will fall several degrees each day through the weekend, bottoming out on Sunday with max temperatures below normal by around 2 to 6 degrees. One exception will be Paso Robles, which is likely to see another drastic 10+ degree drop in temperatures today, as a cool southerly seabreeze will moderate temperatures. Coastal areas will be much less affected by the cooling airmass aloft. Strong onshore pressure gradients are forecasted through the period. This will drive continued marine layer clouds and strong sea breezes, which will keep temperatures relatively constant at the coasts through the weekend (mid 60s to low 70s). The marine layer is currently around 1700 ft deep with a strong inversion aloft, which is significant lifting by a Catalina Eddy compared ydy evening. The lifting will make drizzle possible this morning for LA and Ventura Counties. Low clouds are currently creeping inland, and have reached the Santa Clarita Valley and foothill locations. Clearing is expected to occur by the late morning or early afternoon each day, except for beaches where clouds are likely to persist all day. No major changes in cloud cover through the weekend, except for slight deepening (further inland extent) each day. There is good agreement between the GFS and ECMWF that a cutoff low will to set up to the southwest of SoCal Sunday night. This cool low pressure system has the potential to disturb the warm capping inversion and scattering out the marine layer. The more likely scenario is that the system will lift the marine layer which would result in overnight- to- morning drizzle. The strong onshore pressure gradients will continue to drive southwest winds across the Antelope Valley and foothills. Wind gusts 30 to 40 mph will be common, and gusts up to 45 mph are possible for the foothills. A Wind Advisory has been issued for this afternoon into tonight for the western Antelope Valley foothills, as the local enhancement for this zone may result in advisory level wind gusts with little upper level support. .LONG TERM (MON-THU)...07/338 AM. Next week there is high model agreement that the dominant synoptic feature will be a cut off low, that is likely to stall to the southwest of the region before slowly traveling eastward. The center of the low pressure system will pass either to the south or directly over SoCal on Thursday or Friday. Overall weather conditions will be fairly constant during the period. At the surface, strong onshore pressure gradients are expected to continue. The marine layer pattern will be similar each day, as June Gloom will prevail. Overnight and morning clouds will extend over coasts and valleys and up to the foothills. Daytime clearing and sunshine is likely by midday, except with strong onshore gradients clouds may continue to cling to the beaches all day. High temperatures will show dramatic differences from the coasts to the deserts. Expect 60s to low 70s at the beaches, 70s to low 80s for the valleys, and in the 90s in the Antelope Valley. The cutoff low has the potential to lift the marine layer, thus drizzle is possible each night into morning. During the afternoon, instability brought about by the low pressure system may yield cumulus cloud development over the mountains, but with little mositure, showers are unlikely at this time. Towards the latter part of the week, when the upper low has a chance of passing directly over the region, there is a chance that the low pressure will disturb the capping inversion and scatter out the marine layer, leading to widespread clearing. && .AVIATION...07/1201Z. At 1115Z at KLAX, the marine layer was 1600 ft deep. The top of the inversion was at 4500 ft with a temperature of 25 degrees C. High confidence in TAFs for KWJF and KPMD. Moderate confidence for all other coastal and valley TAF sites. There is a 20% chance for brief cigs at KPRB thru 15Z. Vis values will likely change frequently through 15Z. Flight Cat changes may occur +/- 90 minutes from fcst time. Cig hgts may be off by 200 ft. KLAX...Moderate confidence in TAF. VIS will likely vary frequently between 2SM and 4SM through 16Z. There is a 25 percent chc that CIGs will remain above 005 tonight. No significant easterly wind component is expected. KBUR...Moderate confidence in TAF. VFR conds could arrive as early as 19Z or as late as 21Z. Low clouds arrival tonight could be as late as 08Z. && .MARINE...07/248 AM. For the Outer Waters, moderate to high confidence in current forecast. Tonight through Saturday morning, high confidence in winds and seas remaining below Small Craft Advisory (SCA) levels. From Saturday afternoon through Sunday night, there is a 50-60% chance of SCA level winds. For Monday and Tuesday, high confidence in winds and seas remaining below SCA levels. For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Today through Saturday, high confidence in winds and seas remaining below SCA levels. For Sunday, there is a 30-40% chance of SCA level winds in the afternoon and evening hours. On Monday and Tuesday, high confidence in winds and seas remaining below SCA levels. For the Inner Waters south of Point Conception, high confidence in current forecast. Today through Tuesday, winds and seas are expected to remain below SCA levels. Through the weekend, dense fog, with visibility of one mile or less, will continue to impact the coastal waters north of Point Conception during the night and morning hours. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory in effect from 3 PM this afternoon to 3 AM PDT Saturday for zone 381. (See LAXNPWLOX). Heat Advisory remains in effect until 8 PM PDT this evening for zones 382-383. (See LAXNPWLOX). PZ...NONE. && $$ PUBLIC...Schoenfeld/Rorke AVIATION...Rorke MARINE...RAT/Phillips/ASR SYNOPSIS...Cohen/RS weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox