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), 08/329 AM.
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.
08/1057z.
At 1031Z at KLAX, the marine layer was about 1400 ft deep. The top of the inversion was around 3500 ft with a temperature of 21 C.
High confidence in desert TAFs, moderate to low confidence in stratus clearing and arrival times. Most coastal TAF sites will clear between 17-19z. Valley TAF sites will clear 15-17z. IFR to LIFR conditions expected tonight for coastal TAFs. There is a 40% chance of LIFR conditions at KBUR and KVNY arriving 10-12z Saturday.
KLAX, Moderate to low confidence in TAF. Timing of flight cat changes could be off by +/- 2 hours. No significant east wind component expected.
KBUR, Moderate confidence in TAF. Cigs clearing 16-18z
07/952 PM.
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 - reaching around 10 feet 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, NONE. PZ, Small Craft Advisory in effect from 2 PM this afternoon to 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).
