20/939 AM.
Another heat wave is coming this week, peaking Thursday, but remaining well above normal into early next week. There is potential for major or extreme heat concerns for at least the next week.
(tdy-Wed), 20/953 AM.
***UPDATE***
The primary issue this week and likely into early next week is the arrival of the next heat wave. Minimal changes today and Tuesday, but temperatures ramping up Wednesday and peaking Thursday before cooling slightly going into the weekend but still well above normal. Confidence is 90% that at least heat advisories will be required for valleys and other inland areas with roughly a 50-70% that those will be converted to Extreme Heat Warnings either Wed or Thu and lasting in some areas through the weekend. And there's about a 20-40% chance of extending heat advisories to the coastal areas south of Pt Conception.
***From Previous Discussion***
Through Wednesday CA will be under the western edge of a strong upper high sitting atop of the OK panhandle. There will be light flow aloft and hgts will be near 592 dam which is 1 or 2 dam higher than normal for this time of year.
There will be mdt to stg onshore flow to the east through Wednesday but there will only be weak onshore flow to the north. The high hgts will keep the marine layer smooshed down to under 1000 ft and this along with the weak onshore push to the north will limit or prevent any morning low clouds from making it into the vlys (Santa Ynez Vly excepted). The morning low clouds will not cover all the beaches with low clouds struggling to make to VTA and southern SBA counties as well due to the lake of an eddy.
Temperatures will be the main talking point for the short term (and the long term as well). The upper high and weaker than normal onshore flow will team up to bring 2 to 4 degrees of warming today, 1 to 2 degrees on Tuesday and an additional 2 to 4 degrees on Wednesday. Portions of the SBA south coast may see extra warming as locally gusty north winds will affect portions of that area. By Wednesday the cstl area away from the beaches will see highs in the 80s while the vlys sizzle up to 90 to 103 degrees. Most of the lower mtn elevations and far interior will see max temps from 100 to 103 degrees. Almost all max temps will be 4 to 8 degrees above normal. Some areas (notably the SBA south coast and the Santa Ynez range) may need heat advisories on Wednesday.
The Sundowner winds across southern Santa Barbara County could reach low end advisory levels by Wednesday.
(Thu-Sun), 20/312 AM.
The upper high will stay put for Thu and Fri. The high will strengthen some and hgts will bump up to 594 dam. Starting Saturday the high will migrate westward hgts, however, will remain around 594 dam. The onshore flow to the east will weaken some, but the bigger news is that the N/S gradient will turn offshore.
With minimal marine layer and weak offshore flow from the north Thursday will warm another 1 to 3 degrees. Triple digit heat will be common away from the coast with the warmest areas seeing max temps of 104 to 107 degrees. Heat advisories are likely for some inland areas and there is the possibility of heat warnings. The higher than normal hgts will also create a strong inversion which will keep overnight lows well above normal for many vly locations.
Current fcsts show an eddy with a deeper marine layer on Friday with some cooling possible.
More warming is likely next weekend as the high moves to the 4 corners area. This position will bring a chc of monsoon transport into the area and the potential for afternoon convection will be monitored.
20/1131z.
At 0828Z at KLAX, the marine layer was 1000 ft deep. The top of the inversion was at 3000 ft with a max temperature of 26 C.
High confidence in VFR TAFs for KBUR, KVNY, KPMD, KWJF, and KPRB.
Low confidence in TAFs for KSBP, KSMX and KCMA with a 40 percent chc of IFR conds 13Z-16Z. A better chc of low clouds tonight but low confidence on arrival timing.
Moderate confidence in the remaining TAFs for KLAX, KSMO, KLGB, KSMX and KSBP where timing could be off by +/- 2 hours and cig hgts +/- 200 ft.
KLAX, Moderate confidence in TAF. There is a 30 percent chc of OVC008 cigs. VFR conds may arrive as late as 17Z. There is a 30 percent chc of BKN008 conds aft 21/09Z. No significant east wind component expected.
KBUR, High confidence in CAVOK TAF.
20/218 AM.
Conditions are generally expected to remain below Small Craft Advisory (SCA) levels through Tuesday morning. Northwest winds will strengthen Tuesday, rising to SCA levels by Tuesday afternoon, and will likely continue through the rest of the week. Chances also increase for SCA level west to northwest winds in the western half of the Santa Barbara Channel during the same time.
A series of moderate period southerly swells will move through the waters through the week and likely beyond. These swells may impact south facing harbors, including the Port San Luis area.
Ca, High Surf Advisory in effect until 11 PM PDT Tuesday for zones 87-354-362-366. (See LAXCFWLOX). Beach Hazards Statement in effect through Tuesday afternoon for zones 340-346. (See LAXCFWLOX). PZ, NONE.
