16/859 AM.
A few degrees of cooling are expected today with temperatures returning to normal over the weekend. Morning low clouds and fog will return to many coastal areas by Friday and each day through early next week.
(tdy-Sat), 16/913 AM.
***UPDATE***
Temperatures are expected to start trending cooler today as onshore flow increases in response to an upper level trough developing along the Pac NW, though highs will still be 6-12 degrees above normal. Most coast and valley areas today will be 2-5 degrees cooler while desert and other far inland areas remain about the same as Wednesday. A much more noticeable cooling trend will occur Friday with most areas returning to near normal or even slightly below normal temperatures along with increasing low clouds and fog near the coast.
***From Previous Discussion***
2 mb onshore trends both to the N and E along with a weak eddy on Friday morning will bring areas of low clouds to much of coastal areas. The marine layer as well as the onshore trends will bring a substantial drop in max temps of 4 to 8 locally 10 degrees. This cooling will bring max temps to within 2 degrees of normal.
Another 1 or 2 mb increase in the onshore flow on Saturday will bring the afternoon gradients up into mdt to stg levels. Not only will the morning low clouds cover the csts they will xtnd locally into the vlys. Clearing will be a little slower than usual as well. Max temps will not change too much from Friday's values.
(Sun-Wed), 16/253 AM.
Not too much excitement in the xtnd fcst. The large and very warm upper high will remain camped out over the western half of the county. Hgts will change little over the state through the period and will be near 592 dam.
Most of the actual weather will be controlled by the sfc gradients. Look for strong onshore flow on Sunday and then gradual weakening of both the E/W and N/S gradients through next week.
Night through morning low clouds will affect the csts each day. The hgts may be strong enough to keep the marine layer smooshed enough to keep the stratus out (or mostly out) of the lower vlys.
Max temps will not change much from Saturday's slightly below normal reading through Monday. 2 to 3 degrees of warming is on tap for Tue and Wed as the offshore trends continue.
There will be a significant increase in PWATs Sunday and greater than 1 inch values will continue through Wednesday. This will make the temps feel a little more uncomfortable and could lead to some convection over the mtns in the afternoons. At this time there is a 10 percent or less chc of mtn convection in the afternoon, but this fcst could change given the abundance of moisture.
16/1743z.
At 1617Z at KLAX, the marine layer was 1300 ft deep. The top of the inversion was at 2800 ft with a max temperature of 26 C.
High confidence in VFR TAFs for KPRB, KBUR, KVNY, KPMD & KWJF.
Moderate confidence in remaining 18Z TAFs. Timing of CIG/VSBY restrictions may be off +/- 2 hours and flight minimums by one category.
KLAX, Moderate confidence in TAF. Arrival and clearing times of CIGs near 009 (+/- 300 ft) should be accurate within +/- 2 hours of current forecast. There is a 50% chance east wind component reaches 7-8 knots from 17/08Z-17Z.
KBUR, High confidence in VFR TAF. No wind issues expected.
16/738 AM.
Small Craft Advisory (SCA) level northwest winds across the Outer Waters will continue through Friday and will linger locally into the weekend. The coastal jet across PZZ670 is expected to ramp up again this afternoon and evening which has warranted the issuance of a GALE WARNING for this timeframe. Local gusts to 35 kt may still occur this morning. Short-period seas (nearing 10 ft this evening) are expected to continue through at least Friday.
The elevated winds and seas will extend into the western Santa Barbara Channel & especially nearshore waters along the Central Coast this afternoon through late night.
16/135 AM.
The Beach Hazards Statement was allowed to expire earlier this morning as the southerly swell has decreased, and the high tides are expected to be lower than the previous days.
Beginning Sunday, storms over the Eastern Pacific waters well south of the area could produce increasing southerly swell resulting in additional and potentially more significant hazardous beach conditions, especially during late next week.
Ca, Extreme Heat Warning in effect until 8 PM PDT this evening for zones 38-88-349>353-356>358-368>375-378>383-548. (See LAXNPWLOX). Heat Advisory remains in effect until 8 PM PDT this evening for zones 87-341>345-347-348-354-355-362-366-367-376-377-549-550. (See LAXNPWLOX). PZ, Small Craft Advisory in effect until 3 AM PDT Friday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 3 PM PDT this afternoon for zone 670. (See LAXMWWLOX). Gale Warning in effect from 3 PM this afternoon to midnight PDT tonight for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Saturday for zones 673-676. (See LAXMWWLOX).
