Temp |
73.2 °F |
Dew Pt. |
41.6 °F |
Humidity |
32% |
Pressure |
1011.5 hPa rising slowly |
Wind |
0.0 mph NW |
Rain |
0.00 in 0.00 in/hr |
UV index |
--- |
Solar rad. |
100 W/m² |
Tonight Mostly Cloudy then Patchy Drizzle |
Friday Patchy Drizzle then Mostly Cloudy |
Lo 56 °F | Hi 67 °F |
000 FXUS66 KLOX 200256 AFDLOX Area Forecast Discussion...UPDATED National Weather Service Los Angeles/Oxnard CA 756 PM PDT Thu May 19 2022 .SYNOPSIS...19/159 PM. Cooler temperatures will be prevalent along with night through morning low clouds and fog through the weekend as onshore flow strengthens. Low clouds will be stubborn to clear across the Southland Friday and Saturday. A warming trend is expected early next week as high pressure develops. && .SHORT TERM (THU-SUN)...19/755 PM. ***UPDATE*** Minor updates this evening mainly for cloud cover as the marine layer held fairly steady near 2500 feet through the afternoon, but has surged across many of the Ventura County valleys and is bumping up against the San Gabriel Mountain foothills in the San Fernando and San Gabriel valleys. Onshore pressure gradients LAX-DAG reached an impressive +10 mb this afternoon and had not weakened much for several hours. Gusty west winds of 35-40 mph were common through northern mountain slope/canyons and spilling out across the Antelope Valley, where Palmdale gusted to 41 mph around 02Z. Surface gradients weaken overnight, however, an approaching upper trough to the north is generating some stronger winds aloft. This keeps gusty W-NW winds going through the night across the I-5 corridor and across the eastern Ventura County and Los Angeles County mountains. Wind advisories look on-track tonight and will likely be able to let the Antelope Valley advisory expire in the next few hours. Low clouds cleared to about the Santa Barbara Airport earlier in the afternoon, but an eddy over the channel has pushed clouds westward toward Gaviota and they will likely continue to wrap around Pt. Conception and northward along the west Santa Barbara County coast overnight. Model HREF and NBM cloud guidance both have clouds to Santa Maria late tonight and possibly making it near San Luis Obispo by morning. Expect the marine layer to continue to deepen another thousand feet or so by Friday morning with another cooler than normal day for most areas west of the mountains. Winds will not be as strong with the LAX-DAG gradient about 3 mb weaker for Friday afternoon. It will be another tough day to see much clearing from Santa Barbara southward with patchy drizzle likely to occur in the morning hours. ***From Previous Discussion*** Areas south of Pt Conception now firmly in May Gray conditions. Marine layer still around 2500` but expected to deepen tonight to around 3500`. Strong onshore trends and gradients as well as an approaching trough are helping to counter the typical afternoon clearing processes and clouds so far pretty socked in along the coast from Pt Conception all the way to the MX border and beyond. Probably even cloudier tomorrow south of Pt Conception. Gradients expected to be 3-4 mb weaker but with the deepening trend tonight from the trough and likely some drizzle or very light rain in the morning clouds may not even clear out of some of the coastal valleys. So look for temps tomorrow to be well below normal for all areas except the far interior. Marine layer expected to push well into the valleys, lower coastal slopes, and could even get to the edge of the Antelope Valley through the Highway 14 corridor. Typical breezy west winds in the AV again Friday but should be quite a bit weaker than today and tonight. The Central Coast so far staying clear as northwest flow offshore continues. However, those will be weakening some Friday into Saturday and there should be increasing low clouds and fog there in the next day or two, possibly as early as Friday morning as far north as Santa Maria. Temps there should be near to slightly below norms. Big offshore trends Saturday following the passage of the trough to the north and east. Gradients to the east aren`t expected to actually go offshore but significant weakening of the onshore flow should help provide earlier clearing to most areas except possibly the immediate coast. Marine layer depth still expected to be around 3500` but warming aloft during the afternoon should help squash that somewhat and help the clearing trend. A little warming expected with earlier sunshine but still well below normal for the valleys especially. AV should again see a period of northeast winds before shifting back to west in the afternoon. The back and forth gradient trends continue Sunday as strong onshore gradients return. However, rising heights should lower the marine layer depth and at least help inland areas warm up 3-6 degrees from Saturday. And with decent subsidence in the boundary layer most coastal areas should clear out by early afternoon. .LONG TERM (MON-THU)...19/154 PM. Ensembles continue to lean strongly towards a warming trend through the middle of next week. While there are a few members showing temps close to 100 by Wednesday in the valleys, a vast majority of the solutions are in the mid 80s to mid 90s. Moderate to strong onshore flow will keep temps closer to normal near the coast with likely a shallow marine layer in place. Typical breezy winds in the Antelope Valley with low humidities each day but so far no signs of any Sundowner winds in the Santa Barbara area next week. In fact, the SBA-BFL gradient rises to over 9mb next week according to the GFS with slight to moderate southerly flow aloft, so the marine layer may have a tough time clearing along south facing beaches again next week. && .AVIATION...19/1753Z. At 17Z, the marine layer at KLAX was 2600 feet deep. The top of the inversion was at 3600 feet with a temperature of 22 deg C. Moderate confidence overall in the 18Z TAFs. Low clouds with IFR/MVFR cigs were affecting coast and vly TAFs south of Point Conception at TAF start time, but should clear from KBUR and KVNY by 19Z. Clearing is also expected at KSBA, KCMA and KSMO by 23Z. The rest of the coastal airfields will continue to have MVFR cigs thru the day. Low clouds should return to all coastal and valley areas south of Pt Conception this evening. Conditions should be mostly MVFR, except IFR at some airfields for a while tonight. There should be clearing to VFR by 17Z Fri for KVNY and KBUR while coastal airfields will remain under MVFR cigs. The timing of either clearing or onset of low clouds may be off +/- an hour or two. For airfields N of Point Conception, VFR conditions are expected thru the TAF period except for KSMX which has a 20%-30% of IFR conds late tonight into Fri morning. For KWJF and KPMD, VFR conditions will prevail thru the TAF period, altho with strong and gusty W winds there may be brief periods of reduced vsbys at times this afternoon due to blowing dust and sand. KLAX...Moderate confidence in 18Z TAF. MVFR cigs are expected thru the TAF period, altho there is a 20% chance of the low clouds scattering out this afternoon. There is a 70% chance of east to southeast winds exceeding 8-10 knots from 11Z-16Z Fri. KBUR...Moderate confidence in 18Z TAF. VFR conditions are expected this afternoon with a return of low clouds and MVFR conds 03Z-17Z. The timing of the onset and dissipation of the low clouds may be off +/- an hour or so. && .MARINE...19/636 PM. For the Outer Waters, moderate to high confidence in current forecast. Tonight through Friday night, high confidence in Gale force winds across PZZ670/673 (especially western sections) with conditions generally remaining below Small Craft Advisory (SCA) levels across PZZ676. For Saturday through Tuesday, high confidence in SCA level winds across PZZ670/673 and the northwest portion of PZZ676. Additionally, there is a 30-40% chance of Gale force winds across PZZ670/673 Saturday afternoon through Sunday. For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Tonight through Friday night, high confidence in SCA level winds, especially during the afternoon and evening hours. On Saturday, high confidence in winds and seas remaining below SCA levels. For Sunday and Monday, there is a 60% chance of SCA level winds, especially during the afternoon and evening hours. For Tuesday, high confidence winds and seas remaining below SCA levels. For the Inner Waters south of Point Conception, high confidence in current forecast. Tonight through Tuesday, winds and seas will remain below SCA levels. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory in effect until 6 AM PDT Friday for zones 53-54. (See LAXNPWLOX). Wind Advisory in effect until 10 PM PDT this evening for zone 59. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 3 AM PDT Saturday for zone 645. (See LAXMWWLOX). Gale Warning in effect until 3 AM PDT Saturday for zones 670-673. (See LAXMWWLOX). && $$ PUBLIC...EB/MW AVIATION...Sirard MARINE...RAT SYNOPSIS...MW/Hall weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox