08/219 AM.
A warming trend will continue into early next week. Temperatures will reach the mid 70s to 80s across much of the region through Friday, warming to the 80s and 90s over the weekend through Tuesday. 100 degree readings may occur locally in the warmest valleys on Sunday and Monday.
(tdy-Sun), 08/726 AM.
***UPDATE***
Sundowners are expected this evening into the overnight hours. Have issued advisories for SW SB coast and western Santa Ynez range for gusts up to 45 mph. See NPWLOX for more details. Otherwise, the forecast remains on track. ***From Previous Discussion***
High pressure is building over the West coast and will continue to do so through the weekend. There is still a strong marine layer influence today along with a moderate onshore gradient so highs today for most areas will be very similar to Thursday. Onshore flow will weaken slightly Saturday, though most coastal areas will again start the day with some morning fog. However, with those light offshore trends increasing most areas will see 1-3 degrees of warming compared to Friday.
Additional weakening of the onshore flow is expected Sunday as high pressure aloft continues to build over the region. There may still be a shallow marine layer near the coast in the morning but by afternoon highs are expected to be in the mid 90s in the warmer coastal valleys, mid 80s in Downtown LA and other inland coastal areas, and mid 70s at the beaches. In the deserts highs will be getting very close to 100. For this time of year those temperatures would be not quite qualify for any heat hazards.
(Mon-Thu), 08/338 AM.
The hottest day of this particular heat wave is still expected to be on Monday, which also coincides with the weakest onshore flow and highest 500mb heights. Expecting another 1-3 degrees of warming across the area, meaning some of the warmer coastal valleys, including interior SLO County, will reach the upper 90s, while highs elsewhere will be in the 80s to mid 90s. It will be a close call for heat advisories but the most likely areas would be the coastal valleys and possibly interior SLO and Santa Barbara Counties.
Cooling is expected in most areas Tuesday as the high pressure aloft weakens, which in turn will increase onshore flow. Highs will drop 4-8 degrees most areas, though desert areas may need to wait for Wednesday for more significant cooling. By that time highs area-wide will be within a few degrees of normal.
08/1811z.
At 1714Z at KLAX, the marine layer was 2000 ft deep. The top of the inversion was at 3300 ft with a temperature of 19 C.
High confidence in VFR TAFs for desert airfields (KPMD & KWJF).
Moderate confidence in remaining TAFs. Timing of CIG/VSBY restrictions may be off +/- 3 hours and flight minimums by one category. Lowest confidence for KVNY & KBUR which has a 30% chance low-IFR CIGs do not arrive.
KLAX, Moderate confidence in TAF. MVFR CIGs around 018 expected to clear 19-20Z Fri. Patchy IFR CIGs to develop in the area around 04Z. Better coverage expected at 09Z (+/- 2 hours) with IFR CIGs 008. CIGs likely to lift to low MVFR around 15Z Sat. Expecting clearing around 18Z Sat. However, there is a 30% chance CIGs 010 linger through fcst pd. No significant east wind component expected.
KBUR, Low to moderate confidence in TAF. VFR conditions expected through at least 09Z Sat. CIGs 004-008 could arrive 13Z-16Z, but confidence is low with a 30% chance it doesn't occur. No wind issues expected.
08/726 AM.
SCA level NW winds are expected to strengthen each day through Saturday for the outer waters. Winds may approach Gale Force levels today (20% chance), with GALES likely (40-60% chance) Saturday afternoon and evening over the northern two zones, near and NW of Point Conception. For the southern outer zone PZZ676, SCA winds are likely through early Sunday morning.
For the nearshore waters, SCA level winds are likely during the late afternoon into evening hours along the Central Coast and into at least western portions of the Santa Barbara Channel and near the Channel Islands today and possible again Saturday afternoon and evening.
Short period seas will build during this timeframe especially across the outer waters - peaking 10 to 13 ft today through Saturday night.
Winds and seas should diminish throughout the day on Sunday. By Monday, conditions should be much calmer and likely below SCA levels.
Ca, Wind Advisory in effect from 5 PM this afternoon to 2 AM PDT Saturday for zones 349-351. (See LAXNPWLOX). PZ, Small Craft Advisory in effect until 3 AM PDT Saturday for zones 645-650. (See LAXMWWLOX). Small Craft Advisory in effect until 2 PM PDT Saturday for zones 670-673. (See LAXMWWLOX). Gale Watch in effect from Saturday afternoon through Saturday evening for zones 670-673. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Sunday for zone 676. (See LAXMWWLOX).
