Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
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294 FXUS66 KLOX 262122 AFDLOX Area Forecast Discussion National Weather Service Los Angeles/Oxnard CA 222 PM PDT Wed Jun 26 2024 .SYNOPSIS...26/922 AM. Expect cooling temperatures through Friday as high pressure weakens over the area and onshore flow strengthens. Night through morning low clouds and fog will become more widespread through the end of the week. Warmer weather is expected over the weekend and into early next week as high pressure returns. && .SHORT TERM (TDY-SAT)...26/218 PM. Synoptically, the area is under the western portion of a 595 dam high centered over New Mexico and a 558 dam low is dropping down the west coast. By Thursday the high moves to the south and the low begins its trek roughly along the US/Can border. By Saturday the low will make it to the Great Lakes region and the high begins to build back in over northern Texas. By Tuesday the eastPac high begins to move eastward and higher heights look to remain over most of California through the extended. Skies cleared by mid morning except for portions of the central coast. Temperatures are down 3-5 (or more) degrees in most places as the high pressure overhead decreased a bit and onshore winds were slightly stronger this afternoon. N-S gradients will increase across SBA County and thru the I-5 Corridor later today and tonight, so expect some gusty NW to N winds across the western portions of the south coast of SBA County, the western Santa Ynez mtns and thru the I-5 Corridor. Winds are expected to remain below advisory levels in most areas. Expect the marine layer to deepen a bit tonight as the upper low in the Pacific will move into the Pac NW late tonight/Thu, with a trough extending southward into the forecast area. Clouds should be widespread in coastal areas, with the possible exception of the south coast of SBA County due to the northerly flow. Expect somewhat slower clearing of the low clouds on Thursday, with a better chance that clouds will linger at some beaches. With lowering heights and cooling at 850 mb and 950 mb, expect a few degrees of cooling just about everywhere Thu. The exception may be on the south coast of SBA County, where temps may even edge slightly upward due to downslope northerly flow. N-S gradients will peak across SBA County and in the VTU/northwestern L.A. County mtns Thu evening, and winds could reach advisory levels in some areas. A broad trough will linger across the region Friday. Expect little change from Thursday, except that low clouds may be a bit more widespread in the valleys. Additional slight cooling at 850 mb/950 mb may allow for a bit more cooling in most areas Fri. Heights will rise across the region over the weekend as a large upper high in the south central U.S. begins to expand westward. Expect the marine layer to become increasingly shallow, with less in the way of inland and valley low clouds each night. In fact, low clouds may be squeezed out of most valley areas by Sat night/Sun morning. Rising heights/thicknesses, weakening onshore flow, and less low cloud coverage should lead to a few degrees of warming Saturday. .LONG TERM (SUN-WED)...26/222 PM. The peak of the heat will likely be Sunday and Monday. Max temps will probably exceed 100 degrees in the Antelope Valley and the interior valleys of SLO County, with highs near 100 degrees in some of the warmer locations in the valleys of VTU and L.A. Counties. N-S gradients will increase both Sun night and Mon night, which could bring some gusty winds to southern SBA County and the I-5 Corridor, along with a reduction in coastal stratus in southern SBA County. Heights will remain quite high across the region Tue and Wed, although they will lower a bit as the upper high weakens and shifts eastward. Onshore flow will increase each day. The extended pattern into next weekend looks like it will be a hot one. && .AVIATION...26/1811Z. At 17Z over LAX, the marine layer was 1000 feet deep. The top of the inversion was 4000 feet and 23 degrees Celsius. While all sites are VFR now, there is a chance of BKN010 reforming today as early as 20Z at KOXR (30%) and KLAX (10%). High confidence in VFR conditions through Thursday at KPRB KWJF KPMD, moderate confidence at KBUR KVNY. All other sites have a chance ceilings tonight into Thursday: KSBP (60%) KSMX (90%) KSBA (50%) KOXR (80%) KCMA (70%) KSMO (50%) KLAX (50%) KLGB (50%). High confidence that ceilings and visibilities will be similar for the next 24 hours as they have been for the previous 24 hours. Winds will be stronger today than yesterday at KSMX KSBP, and KWJF KPMD where the wind directions will likely have a more northerly component. KLAX...Moderate confidence in VFR conditions through at least 04Z, with a 10% chance of a couple of hours of BKN010 20-02Z. Low confidence on ceilings tonight. 50% chance of BKN008-012 starting as early 03Z and as late 10Z. Southeast winds will likely form after 09Z, but high confidence that they will stay under 8 knots. KBUR...There is a 10% chance of IFR ceilings Thursday 10-15Z, otherwise high confidence VFR conditions through at least Thursday. High confidence in seasonal winds. && .MARINE...26/157 PM. There is a moderate threat for dense fog to form again later tonight into Thursday for the waters off the Central Coast. High confidence in at least Small Craft Advisory (SCA) winds and seas through Friday Night for the Outer Waters (offshore waters of the Central Coast to San Nicolas Island). There is a 60 percent chance of reaching Gales tonight, especially the northern most areas. For Thursday, the chance for Gales increases to 90 percent for that area. High confidence in Gales ending by Friday morning. Moderate confidence in much less wind on Saturday, but winds will pick up again on Sunday. Elsewhere there the SCA level northwest winds will push into the Santa Barbara Channel but high confidence that they will stay confined to the western half. There is a chance that enough of the channel will be covered with these winds to warrant an SCA: 20 percent chance tonight and 40 percent chance on Thursday Night. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...Small Craft Advisory in effect until 3 AM PDT Friday for zones 645-676. (See LAXMWWLOX). Small Craft Advisory in effect until 5 PM PDT this afternoon for zone 670. (See LAXMWWLOX). Gale Warning in effect until 8 AM PDT Thursday for zone 670. (See LAXMWWLOX). Gale Watch in effect from Thursday morning through late Thursday night for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect until 3 PM PDT Thursday for zone 673. (See LAXMWWLOX). Gale Watch in effect from Thursday afternoon through late Thursday night for zone 673. (See LAXMWWLOX). && $$ PUBLIC...DB/jld AVIATION...Kittell/Lewis MARINE...RK SYNOPSIS...jld weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox