27/504 PM.
Temperatures will remain above normal through Monday, especially inland of the beaches, warmest over the weekend. Dense fog will affect coastal areas each day through Saturday or Sunday. Much cooler conditions expected Tuesday through the end of the week, along with gusty winds and a chance of rain at times.
(tdy-Mon), 27/227 PM.
The ridge of high pressure aloft, centered over northern Mexico, will slowly flatten out through Monday, but the pressure will remain abnormally high. Meanwhile, the onshore surface pressure gradients will fluctuate a little each day but remain weakly onshore. All of this adds up to above normal temperatures persisting into next week, peaking this weekend when highs will be 10 to 20 degrees above normal. Near the coast, a persistent but very shallow marine layer will continue to moderate the beaches, with the inland coastal plains caught between the cool ocean air and the warm valley air. Minor, random, and unpredictable ebbs and flows of the marine layer will dictate what side of the 80 degree range that places like downtown LA end up being on. While a record or two will fall, primarily in the Antelope Valley, the heat signature is not extreme enough to need any Heat Advisories.
Low clouds and fog associated with the marine layer will continue to form each night and morning over most coastal areas, with the Central Coast finally joining back into the stratus party tonight. There will be some disruptions to the low cloud evolution Saturday Night into Sunday with moderate northwest winds forming over southwest Santa Barbara County, and maybe on the Central Coast on Monday with a weak offshore push. Otherwise, June Gloom in March is pretty set in. Dense fog cannot be ruled out tonight into Saturday, but the chances will be lowering going forward.
(Tue-Fri), 27/236 PM.
High pressure aloft finally breaks down Tuesday as a deep and cold low slams into the Pacific Northwest Tuesday through Thursday. This will drop temperatures sharply everywhere on Tuesday and strengthen onshore flow. Most high temperatures will be down 15 to 20 degrees on Tuesday compared to Sunday and back to around normal. Minor changes expected to follow through Friday.
The low will spawn a cold front that will sweep down the west coast. A few days ago, most of the projections held that front together and produced some light to moderate rain. Today, that scenario is the minority, as the low now looks likely to take more of a northerly track and cut off the energy feed to the front by the time it reaches San Luis Obispo County. As a result, maybe 20 to 40 percent of the solutions have any rain in the Tuesday through Thursday time period, and the rain-free streak now is more likely to continue into April.
What the front will do however is spin up some healthy post frontal winds. Widespread gusty west to northwest winds are still favorable Wednesday through Friday, with a number of Wind Advisories likely.
28/0003z.
At 2230Z at KLAX, there was a 900 ft marine layer. The top of the inversion was at 2200 feet with a temperature of 21 C.
High confidence in TAFs for KPRB, KPMD, KWJF, KBUR, and KVNY.
Low to moderate confidence in remaining TAFs. Low clouds and fog with predominantly LIFR conds expected for the overnight period. However, lower confidence exists in the arrival time of low clouds, which could differ by +/- 2 hours from TAF times. Conditions could be off by one flight category and there is a 20% chance of LIFR conds down to 1/4SM FG at any of the airfields.
KLAX, Low to moderate confidence in the 00Z TAF. Expecting a faster return of cigs this evening, most likely in the 02-03z time range. When cigs do develop, fairly high confidence of LIFR to IFR cigs, with a 10-20% chance of VLIFR conditions down to 1/4SM FG. No significant east wind component expected.
KBUR, High confidence in the 00Z TAF. VFR conditions expected through period, with a small chance (10-20%) of mvfr vsbys in haze early Saturday morning.
27/221 PM.
High confidence in winds and seas staying under Small Craft Advisory (SCA) levels through at least Monday, except for a 50% chance of low-end SCA winds beyond 20 miles from the Central Coast starting Saturday Night.
Moderate risk for dense fog with visibility under one mile will continue through at least Saturday.
There is a growing risk for widespread strong SCA or low-end Gale Force winds over most coastal waters (including nearshore and the Santa Barbara Channel) Wednesday through Friday of next week.
Ca, NONE. PZ, NONE.
