15/854 AM.
Dry and warmer weather is expected for the remainder of this week. Gusty northerly winds will develop over much of the area on Thursday, shifting to northeast and becoming focused over Los Angeles and Ventura Counties on Friday. The next chance of rain will be next Monday.
(tdy-Fri), 15/912 AM.
***UPDATE***
Overall today will look and feel a lot like Tuesday, except most areas will be 1-3 degrees warmer by afternoon. There is a light offshore trend this morning that will be just enough to delay the sea breeze long enough to warm things up a little.
Increasing northerly winds are expected in the mountains later tonight into Thursday morning. Will likely need some wind advisories there.
Not much change in the forecast the rest of the week. As mentioned below there will be a lot if high clouds moving in later tonight through tomorrow morning then clearing out later in the day. Minimal changes in temperatures.
Winds will shift to northeast Friday resulting in a moderate Santa Ana wind event. There is some uncertainty how much of an easterly component this event will have, which impacts where the strongest winds will be. There is high confidence in at least advisory level winds, and the usual spots in the San Gabriel and Santa Susana Mountains will likely reach 50-60 mph.
***From Previous Discussion***
The upper low associated with the forecast inside slider is not fcst to be much further to the NE than before and only its trof will move down the CA/NV state line. The RRFS came with much less wind which seem reasonable but the NAM still has gusty winds through the i-5 corridor. Low clouds should be pretty minimal again and mostly confined to western SBA county and perhaps the Long Beach area again. There is a chc of an eddy spinning up and if this happens there will be more low clouds than fcst.
Thursday actually looks like it will start off mostly cloudy as a grip of mid and high clouds stream over the area. These clouds should slowly move off during the afternoon for SLO, SBA and VTA counties but LA county might have clouds all day. The northerly offshore flow is forecast to bring a few degrees of warming to the LA/VTA csts and VLys and 3 to 5 degrees fore the csts/vlys of SLO and SBA counties. This is a lower confidence fcst, however, due to the amount of high clouds and 6 mb of onshore flow to the east in the afternoon. Would not be surprised if there was only limited or no warming instead. The northerly flow will bring in cool air from the SAn Joaquin Vly and this will cool the far interior by 2 to 4 degrees.
High pressure rapidly building into the Great Basin in the wake of the inside slider will quickly switch the onshore flow to the east to offshore. The latest runs suggest about 6 mb. There will be about 4 mb of offshore flow from the north as well. This combined with decent winds at 850 mb should produce an advisory level Santa Ana wind event with 45 to 55 mph gusts through the Santa Ana Wind Corridor (Santa Clarita Vly to the western Santa Monicas). Sunny skies and offshore flow will bring 3 to 6 degrees of warming to the LA/VTA csts/vlys. Cool air from the NE will lower temps across the Antelope Vly by 2 to 4 degrees. The lack of northerly flow over the Santa Ynez range will cool the SBA south coast by 2 to 3 degrees. Most cst/vly max temps will end up in the 70s and lower 80s (The SBA south coast may only reach the upper 60s)
(Sat-Tue), 15/221 AM.
The upper level flow turns to the west on Saturday. There will still be offshore flow in the morning but it will be weaker than it was on Friday. The weaker flow and lack of upper support means that while there will be canyon winds in the morning they will not be strong enough for an advisory. Skies will be sunny and it will be a very warm day. Look for 1 to 2 degrees of warming across the csts; 3 to 5 degrees in the vlys, while the mtns and interior will see 4 to 8 degrees of warming as the cool air from the interior shuts off. Most max temps will be 6 to 8 degrees above normal.
On Sunday offshore flow will be turning onshore as another cold and cut off upper low approaches northern California. The csts and vlys will cool 2 to 4 degrees with the earlier and stronger sea breeze. The interior will actually warm a few degrees.
No real resolution to the Monday Tuesday forecast as there is disagreement in the deterministic mdls and a wide spread within the ensembles. The is reflected in the official NBM forecast that shows 48 hours of slight chc pops Monday through Tuesday. With the low to the north the best chc of rain will be north of Pt Conception. LA county currently only has very minimal chances of rain.
15/1505z.
At 1500Z at KLAX, the marine inversion was 1200 feet deep. The top of the inversion was 3200 feet with a temperature of 12 degrees Celsius.
For the 18Z TAF package, moderate to high confidence in current forecasts. Through this evening, high confidence in CAVU conditions for all sites. For tonight, there is a 50% chance that CIG/VSBY restrictions do not develop at KLAX, KSMO and KLGB. Also, there is a 30% chance of CIG/VSBY restrictions at KSMX after 08Z.
KLAX, Moderate to high confidence in 18Z TAF. High confidence in CAVU conditions through this evening. For tonight, there is a 50% chance that CIG/VSBY restrictions do not develop. If CIG/VSBY restrictions do develop, timing of return could be +/- 3 hours of current forecast. No significant easterly wind component is expected.
KBUR, High confidence in 18Z TAF as CAVU conditions are expected through the period.
15/805 AM.
For the Outer Waters, moderate to high confidence in current forecast. Today through Friday, high confidence in a combination of Small Craft Advisory (SCA) level winds and seas. On Thursday and Thursday night, there is a 40-50% chance of GALE force winds, mainly across far northern waters & south of Pt Conception. For Saturday through Sunday, there is a 30-40% chance of SCA level winds.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Today through Thursday, high confidence in SCA level winds during the afternoon and evening hours with a 20% chance of GALE force wind gusts Thursday evening. For Friday through Sunday, there is a 20-30% chance of SCA level winds during the afternoon and evening timeframe.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Through tonight, there is a 30-40% chance of SCA level winds across the western half of the Santa Barbara Channel then a 50-60% chance of SCA level winds in this same area Thursday afternoon/evening. Otherwise, winds and seas will remain below SCA levels through Thursday night. On Friday, there is a 50-70% chance of SCA level northeast winds from Ventura south to Santa Monica and potentially across the San Pedro Channel. For Saturday thru Sunday, high confidence in winds and seas remaining below SCA criteria for all southern Inner Waters.
Ca, NONE. PZ, Small Craft Advisory in effect until 3 PM PDT this afternoon for zones 670-673-676. (See LAXMWWLOX).
