16/146 PM.
It will be warm and muggy through Friday as remnants of tropical storm Mario move into the area. Temperatures will cool through the period but humidities will be much higher than normal. Rain and thunderstorm chances will begin Wednesday night and continue into at least early Friday. Over the weekend into early next week there is slight chance of showers as additional moisture from the south arrives. Temperatures will be near normal and the muggy weather will continue into early next week.
(tdy-Fri), 16/215 PM.
Moisture from what was Tropical Storm Mario is rapidly moving up the Baja coast and will be entering US waters overnight tonight. It's been an active day of thunderstorms across the spine of northern Baja but so far no convection on this side of the border. While there still remains a lot of uncertainties, confidence is growing that most areas across the 4 county area will get at least some rain between Wednesday afternoon and Thursday. Amounts are going to be highly variable, with some areas possibly just getting around a tenth of an inch, and other areas (possibly not that far away) as much as 1-2 inches. As of now the higher rain amounts are expected in the mountains south of Pt Conception, but if Mario's track reverts back to its farther west solution then heavier amounts could reach the Central Coast. There are also some signals in the models indicating the potential for severe weather, including an isolated small tornado. The best chance for any lightning would likely be as the moisture is just arriving Wednesday night into early Thursday, after which the environment may be too moist with with too much cloud cover to support thunder development. Rain rates up to at least a half inch are possible with the heavier cells, and can't rule out rates as high as an inch per hour given the 2+" of precipitable water.
Needless to say it will become increasingly muggy later Wednesday into Thursday. Temperatures are expected to cool a few degrees in most areas Wednesday and several more degrees Thursday with increasing cloud cover and showers. Overnight lows will be much warmer than normal as well as the moisture aloft will trap a lot of the heat from the daytime.
Precip chances will decrease later Thursday night into Friday morning and should be completely gone by Friday afternoon. Temperatures will still be 5-10 degrees below normal, but with still much higher than normal humidity it will feel much warmer.
(Sat-Tue), 16/231 PM.
The weekend forecast has become less certain as there are some models now bringing up some additional moisture and instability that could trigger isolated showers. This may end up just being over the mountains but if there's any left over instability after Mario departs it may not take much to trigger an brief shower. The most likely outcome is a dry weekend with temperatures warming back to normal levels and still with elevated humidity levels.
Next week is also uncertain as another tropical wave over Mexico moves out over the Pacific. The upper level pattern may be favorable to get some of that moisture into the area early next week but will have to see how the pattern evolves the next few days. There also some model solutions indicating a strong high pressure system developing over southern California with the potential for triple digit heat to return to the valleys.
16/1652z.
At 1630Z at KLAX, the marine inversion was around 500 feet deep. The top of the inversion was 1700 feet with a temperature of 28 degrees Celsius.
For the 18Z TAF package, high confidence in valley and desert TAFs as VFR conditions are expected through the period.
For coastal TAFs, low to moderate confidence in 18Z TAFs. Moderate confidence in KSMX with timing of flight category changes +/- 2 hours of current forecast. For remainder of coastal TAFs, there is a 20-30% chance of LIFR/VLIFR conditions 08Z-16Z.
KLAX, Overall, moderate confidence in 18Z TAF. High confidence in VFR conditions through this evening. For tonight, there is a 30% chance of LIFR/VLIFR conditions 09Z-16Z. No significant easterly wind component is expected.
KBUR, High confidence in 18Z TAF as VFR conditions are anticipated through the period.
16/144 PM.
For the Outer Waters, moderate to high confidence in current forecast. Tonight through Saturday, high confidence in winds and seas remaining below Small Craft Advisory (SCA) levels. On Sunday, there is a 30-50% chance of SCA level winds, especially across PZZ673/676.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Tonight through Saturday, high confidence in winds and seas remaining below SCA levels. On Sunday, there is a 20-30% chance of SCA level winds in the afternoon and evening hours.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Tonight through Saturday, high confidence in winds and seas remaining below SCA levels. On Sunday, there is a 20-30% chance of SCA level winds across western sections.
For Wednesday through Friday, the remnants of Tropical Storm Mario will impact the Southern California coastal waters. A period of showers, most likely late Wednesday and Thursday, will move over the waters. Additionally, there will be a chance of thunderstorms. Any thunderstorms that develop will be capable of frequent lightning as well as strong and erratic winds. Please monitor the forecast if you have any plans on going out on the water this week.
Ca, Heat Advisory in effect until 7 PM PDT this evening for zones 88-357-358-362-369>374. (See LAXNPWLOX). PZ, NONE.
