19/245 AM.
Night through morning marine layer clouds will be confined to the coastal areas, mostly north of Pt Conception, through much of this week. Warmer and drier conditions are expected away from the immediate coast, with the heat peaking today and Thursday, when moderate heat risk is expected in warmest locations.
(tdy-Fri), 19/759 AM.
***UPDATE***
Latest satellite and surface observations indicate mostly clear skies except for some Central Coast stratus/fog and a patch off the Ventura/LA coast. Current sounding data indicates marine layer ranging between 800 and 1000 feet in depth. Still some lingering northerly winds (gusting to 35 MPH) across southern Santa Barbara county.
Forecast-wise for the immediate short term, no significant changes are expected. Main concern today will be the heat. 12Z TEMP STUDY data indicates very similar conditions to yesterday with a little bit warmer boundary layer. So, the inland coastal plain will climb into the 80s to around 90 today with the valleys and mountains topping out in the mid 90s to 105. So, current HEAT ADVISORIES still look to be on track with widespread moderate heat risk.
Other than the heat, weather issues will be minimal today. Sunny skies can be expected for areas today after morning stratus dissipates. There will be some locally gusty Sundowners this evening, but not widespread enough to warrant any type of wind product.
Current forecast looks good for the immediate short term. So, no significant updates are expected.
***From Previous Discussion***
Today and Thursday will be the warmest days of the next 7 with heat hazards continuing for may vlys areas as well as the lower mtn elevations. 596 dam hgts (6 dam above normal), weaker than normal onshore flow and a greatly reduced marine layer will bring max temps of 95 to 105 degrees to many areas away from the csts. Even the interior coastal sections (such as DTLA) will have max temps in the lower 90s. Heat Advisories are in effect for the LA vlys and all of the lower mtn elevations. People outside of the advisory area still need to take precautions from the heat which will be 4 to 8 degrees above normal.
There will be some cooling on Friday, but perhaps not enough to eliminate the need for heat products esp considering that the humidities will be rising courtesy of the developing SE flow around the upper high which is fcst to move over the 4 corners area. This SE flow will also bring enough mid level moisture to create a 10 to 15 percent chc of convection over the mtns and Antelope Vly in the afternoon.
Gusty north winds will affect southwest Santa Barbara County and the I-5 corridor near the Grapevine each evening and overnight. The gusts should almost all be below advisory levels with only a chance of isolated advisory level (45 mph) gusts in the Gaviota area.
(Sat-Tue), 19/245 AM.
All medium range models agree the the upper high will shift to the east in response to an upper low moving towards the coast. Hgts do not change that much and will hover around 594 dam. Gradients do not change too much through Monday, but offshore trends develop on Tuesday and Wednesday.
The weather will be pretty benign. There will be better low cloud coverage each night and morning.
Max temps will cool some with the best cooling across the Central Coast which is closest to the upper trof. Max temps will remain above normal for most areas south of Pt Conception, while below normal temps are slated for SLO and most of SBA counties.
The monsoon flow will weaken as the flow direction will not be optimal, but a 5 to 10 percent chc of mtn convection Sat and Sun.
19/1717z.
At 1702Z at KLAX, the marine layer was 1000 feet deep. The top of the inversion was at 3500 feet with a temperature of 26 C.
High confidence in VFR TAFs for KPMD, KWJF, KPRB, KBUR, and KVNY.
Good confidence in TAF for KSBP & KSMX, timing of arrival of marine layer clouds could be +/- 2 hours of forecast. Min cig height may be off +/- 200 feet.
Low confidence in remaining TAFs after 06Z. There is a chance for low clouds at KSBA (20%), KOXR (30%), KCMA (30%), KSMO (50%), KLAX (60%), and KLGB (60%). Low clouds would likely develop over LA County between 06Z-12Z, then KOXR/KCMA/KSBA possible after 10Z. Lower confidence in cig heights, but likely between 004-008, except higher at KLGB.
KLAX, Low confidence in TAF after 06Z. There is a 40 percent chance of no low clouds tonight, but if they do occur, likely BKN006-010 arriving between 06Z-12Z. Any east wind component is expected to remain below 8 kt.
KBUR, High confidence in VFR TAF. No wind issues expected.
19/841 AM.
Moderate confidence in Small Craft Advisory (SCA) winds across the Outer Waters through Sunday. Conditions may dip below criteria levels during the morning hours each day. Short period, choppy seas are likely through the weekend.
For the Inner Waters north of Point Sal, there is a low to moderate chance of SCA level winds through Thursday, then increasing chances Friday into the weekend, with strongest winds focused during the afternoon through evening hours.
For the Inner Waters south of Point Conception, SCA level winds are likely to reach into the western portion of the Santa Barbara Channel each afternoon and evening through the weekend, except lower chances Thursday and Friday. Aside from local wind gusts to 20 kt in the San Pedro Channel, conditions are expected to remain below advisory levels elsewhere.
Ca, Heat Advisory in effect until 8 PM PDT Thursday for zones 38-88-343>345-351-353-371>373-375-376-379-380-548. (See LAXNPWLOX). PZ, Small Craft Advisory in effect until 3 AM PDT Thursday for zones 670-673-676. (See LAXMWWLOX).
