24/909 PM.
Marine layer clouds with patchy fog will reoccur each night from the coasts to the coastal valleys, expanding into the valleys into this weekend. Temperatures will trend cooler, with below normal temperatures for Friday into the weekend.
(Wed-Sat), 24/908 PM.
***UPDATE***
Heights peaked today around 590 DAM, and high temperatures although warm, were not quite as hot as expected with 80s to low 90s common for many valleys and mid to upper 90s for far interior areas. Marine layer clouds this morning continued to push near the coastal valleys, especially along the Central Coast, helping to limit warming. With ongoing solid onshore flow and falling heights, temperatures will trend cooler into the weekend with a deepening marine layer. Light drizzle overnight cannot be ruled out as well. Temperatures were cooled Thursday and Friday, more in line with the marine layer and expected trends. Given the cooler solution for Thursday, the Heat Advisory for the LA County valleys has been expired.
***From Previous Discussion***
A 590 dm ridge is currently situated over Socal. This ridging is expected to break down on Thursday and will be replaced with zonal to cyclonic flow as another trough develops over PACNW and dives into the Great Basin through the weekend.
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, and even better chances into the weekend. Advisory level Sundowner winds likely on Friday, and especially on Saturday. Focused across western Santa Ynez range.
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.
Temperatures are expected to be warmest today and a couple degrees cooler tomorrow (still warm/hot). Then, a noticeable cooling trend Friday into the weekend.
Important: Have adjusted the Heat advisory end time to 9 PM Wednesday for zone 368 - Los Angeles Inland Coast including Downtown. All other zones are still under a heat advisory through 9 PM Thursday. See NPWLOX for more details.
(Sun-Wed), 24/1245 PM.
June Gloom will be back with a vengeance during the xtnd period. By Sunday, an unseasonably cold upper low will be situated over the Great Basin region. This main low will lift to the NE on Monday. In Tandem, a shortwave will drop south on the backside and will maintain troughing over the west coast. There is some uncertainty in how far south the energy dives.
Chances for advisory level winds linger into Sunday across the Antelope Valley/adjacent foothills and I-5 corridor. Lower confidence beyond due to uncertainty in upper pattern and sfc pressure gradients.
At least moderate onshore flow to the north and east is expected to continue Monday through Wednesday. Look for plenty of night through morning low clouds across the csts/vlys every day. Clearing will be on the slow side and a few beaches will remain cloudy in the afternoon. Portions of the SBA south coast may be the exception as local north flow indicated by the KSBA-KSMX gradients may keep the low clouds away or to a lesser extent.
Temperatures are likely to remain below normal through end of fcst period. Max temps will mostly be in the 70s across the csts/vlys (mid to upper 60s at the beaches) and only lower to mid 80s for the inland areas. These max temps are 3 to 5 degrees cooler than normal at the csts and 5 to 10 locally 12 below normal across the vlys and inland areas.
25/0350z.
At 0326Z at KLAX, the marine layer was 1000 feet deep. The top of the inversion was 3400 feet with a temperature of 22 C.
High confidence in TAFs for KPMD & KWJF.
Moderate to high confidence in the KPRB TAF. There is a 10% chance for IFR CIGs tonight.
Moderate confidence in the remainder of the TAFs. Timing of CIG/VSBY restrictions could be +/- 2 hours of current forecast.
KLAX, Moderate confidence in TAF. MVFR CIGs expected to persist overnight with increasing chances for IFR CIGs after 06Z.
KBUR, Low to moderate confidence in TAF. Similar probability of 30-40% for MVFR/IFR CIGs for a short period tonight, most likely between 08-15Z.
24/155 PM.
High confidence in winds and seas remaining below Small Craft Advisory (SCA) levels through today. Local gusts could reach 21 kts near Point Conception and across the western Santa Barbara Channel later this afternoon into the evening. Chances for SCA criteria gusts increase Thursday evening across the northern waters and will expand to the south Friday into the weekend. SCA winds will be strongest on Saturday, and will reach into the nearshore waters along the Central Coast and Santa Barbara Channel at times. Seas will near 10 ft Saturday evening through Monday morning. Thereafter, conditions look to quiet down a bit through mid next week.
Ca, NONE. PZ, NONE.
