14/904 AM.
A warming trend will continue through Wednesday, with dangerous expected for many areas through Thursday. A few showers and thunderstorms may affect the mountains and the Antelope Valley this afternoon. Gusty northwest to north winds are forecast for southern Santa Barbara County and the LA and Ventura interior mountains during the afternoon and overnight hours today and especially Wednesday. Cooler weather will begin to arrive on Thursday.
(tdy-Thu), 14/937 AM.
***UPDATE***
Hot and muggy weather again today. The biggest change today is the decrease in mid and high level cloud coverage as those have shifted a bit to the east. However, PW's remain around 1.75" so even though skies are clear this morning convective cloud coverage is expected to increase quickly this morning over the higher terrain and chances for showers and thunderstorms remain around 30-40% by this afternoon. Not expecting storms at lower elevations but there could be a few light showers in the foothills. Given the high water content and moderately unstable airmass with CAPEs in the 500-800j/kg range some brief heavy rain and localized flooding is possible in the mountains.
***From Previous Discussion***
Over the next three days CA the state will be under the western edge of large and hot upper high. Hgts will wobble between 590 dam and 592 dam. The sfc pressure gradients will be the most important factor in the forecast. The E/W gradient will likely be weakly onshore in the morning becoming mdt onshore in the afternoon. This gradient will also become a little more onshore each day. The N/S gradient will likely be weakly offshore in the morning and weakly onshore in the afternoon. There is a 30 percent chc that there will be offshore flow from the east on Wednesday morning.
The high hgts and weaker than normal onshore flow will team up Today and Wednesday to bring two days of warming. Most areas will see 3 to 6 degrees of warming today with the exceptions of the Antelope Vly which will likely see 8 to 10 degrees of warming and the Central Coast where a stronger sea breeze will bring a little cooling. Wednesday will be the warmest day with another 3 to 6 degrees of warming on tap for the entire area. This warming will bring 100 to 110 degree heat to the vlys, lower mtn elevations and the far interior on Wednesday. The increase in onshore flow will bring some cooling on Thursday, but not enough to eliminate the heat risk. The Extreme Heat Warnings and Heat Advisories in effect for most of the area will persist through Thursday evening. Please see the product LAXNPWLOX for all of the details. During the heat wave, it is very important to avoid the heat of the day as much as possible, especially between 10AM and 7PM.
There will be one more day of monsoonal moisture moving into and over the area within the upper high's circulation pattern. This mositure will bring a 20-40 percent chc of showers/TSTMs to the mountains and Antelope Vly. The highest chc of convection will occur over the eastern San Gabriels and the higher Ventura Mountains.
Strong Sundowner winds are forecast for the SBA south coast with over 4mb of an offshore push from both the KSMX and KBFL gradients. Northerly winds with gusts 30-00 mph will affect most of the SBA south coast tonight. The Sundowner winds will peak Wednesday evening with gust 35-50 mph (local gusts to 60 mph are possible in the foothills). These winds with their adiabatic compressional heating could bring temps in the 90s all the way to the beaches with triple digit heat in the foothills. The hot and dry conditions will greatly increase the fire danger and a Fire Weather Watch is in effect for all of the Santa Barbara South Coast and Mountains Wednesday into Thursday morning.
(Fri-Mon), 14/226 AM.
Very little change in the synoptic pattern during the long term. Hgts will sit around 592 dam through the period. The sfc gradients will be the bigger news as they will both trend onshore and become mdt to stg.
There will be night through morning low clouds and fog across the csts xtng locally into the vlys.
Max temps will nose dive 6 to 12 degrees on Friday. This cooling will bring max temps to or even a few degrees blo normal. After Friday temps will not change much day to day as the synoptic situation will not change much.
PWATs will remain around 1 inch and there will be a non zero chc of some afternoon mtn showers, but more likely just some cloud build ups. Long range mdls do show a generous uptick in moisture due to the movement of a tropical system next Tuesday.
14/1720z.
At 1610Z at KLAX, the marine layer depth was 1100 ft. The top of the inversion was at 3000 ft with a max temperature of 26 C.
Moderate to high confidence in VFR TAFs at all sites, highest away from coasts. There is a 30% chance for LIFR to IFR cigs at KLAX/KSMO/KLGB/KSMX after 08Z (except after 04Z at KSMX).
There is a 10-20% chance for thunderstorms at KPMD/KWJF from 19Z to 02Z. Biggest threat would be gusty erratic outflow winds up to 50 kt, turbulence, and lightning. There is also a chance for a brief heavy downpour.
KLAX, Good confidence in TAF. There is a 30 percent chc of BKN004-007 cigs after 08Z, with best chances BKN005-007. No significant east wind component expected.
KBUR, High confidence in TAF. 10% chance for 10kt west winds from 01Z-04Z.
14/905 AM.
Northwest winds are expected to strengthen to Small Craft Advisory (SCA) levels across the Outer Waters this afternoon and will continue through Thursday night. There is also 20% chance of Gales later Wednesday into Thursday. Seas are forecast to build to near 10 feet in conjunction with these winds. The elevated winds and seas will extend into the western Santa Barbara Channel and nearshore waters along the Central Coast each afternoon and evening through Thursday night.
Winds are expected to improve Friday through the weekend while the northwest swell lowers. Hhowever, short period choppy seas from a southerly swell assocaited with a tropical system to our south and west will impact our waters this weekend.
14/905 AM.
Dangerous rip currents and breaking waves with elevated surf are expected for coastal areas and the beaches of Los Angeles, Ventura, Santa Barbara, and San Luis Obispo Counties, as enhanced southerly swell continues. Minor coastal flooding will be possible during the evenings, given abnormally high tides of 7.0 to 7.6 feet. A Beach Hazards Statement remains in effect through Wednesday evening for these areas.
For this weekend, distant storms over the East Pacific waters well south of the area could produce increasing southerly swell resulting in even more significant beach hazards.
Ca, Extreme Heat Warning in effect until 8 PM PDT Thursday for zones 38-88-349>353-356>358-368>375-378>383-548. (See LAXNPWLOX). Heat Advisory remains in effect until 8 PM PDT Thursday for zones 87-341>345-347-348-354-355-362-366-367-376-377-549-550. (See LAXNPWLOX). Beach Hazards Statement in effect through Wednesday evening for zones 340-346-349-350-354-362-366. (See LAXCFWLOX). Fire Weather Watch in effect from Wednesday afternoon through Thursday morning for zones 349>353-376>378. (See LAXRFWLOX). PZ, Small Craft Advisory in effect until 9 PM PDT this evening for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect from 3 PM this afternoon to 3 AM PDT Wednesday for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Friday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect from 3 PM this afternoon to 3 AM PDT Friday for zones 673-676. (See LAXMWWLOX).
