06/223 AM.
A warming and drying trend will begin today and continue through at least early next week. During the peak of the heat on Mothers Day and next Monday, high temperatures are expected to be in the 80s and 90s, with a possibility of 100 degrees in the warmest valleys.
(tdy-Fri), 06/322 AM.
The low pressure system that brought cool temperatures and scattered showers has moved south into Mexico and high pressure will be quickly building behind it. This is not going to be a Santa Ana event, but there will be a decrease in onshore flow which will delay the sea breeze arrival and allow the beaches to warm up as well. Overall, temperatures will warm 5-10 degrees both today and Thursday, pushing up highs into the 70s and 80s, warmest in the valleys. By Friday the warmest valley areas will be close to 90 while inland coastal areas will be in the 70s to lower 80s.
(Sat-Tue), 06/333 AM.
The high is expected to remain over the West coast at least through next Tuesday, with 500mb heights reaching 590dam, which is between the 97th and 99th percentiles, indicating a very rare event. The hottest days will be on Mother's Day and Monday. During those peak heat days most valleys will be in the 90s with a 15-30% chance of reaching 100 in the western San Fernando Valley and the interior parts of San Luis Obispo County. These temperatures would be at least 20 degrees above normal.
Closer to coast temperatures will not be as hot but still at least 10-15 degrees above normal with highs in the upper 70s and 80s. Downtown LA has about a 30% chance of reaching 90 on the hottest days.
Given the highly anomalous temperatures over multiple days there is a chance that heat hazards will eventually be needed in some areas, at least for the two hottest days Sunday and Monday. That decision will likely happen either Friday or Saturday.
06/0915z.
At 12Z at KLAX, the marine layer was around 2500 feet deep. The top of the inversion was 3500 ft with a temperature of 12 degrees Celsius.
High confidence in VFR TAFs for desert airfields (KPMD & KWJF).
Low confidence in remaining TAFs. Patchy MVFR CIGs possible across the LA Basin through 18Z and IFR CIGs for KSMX, KSBP, and KPRB through 15z. There is a 20% chance low clouds do not develop at KPRB. For all sites with forecasted CIGs, low confidence in arrival times.
KLAX, Low confidence in TAF. 40% chance CIGs do not develop. High confidence that any east wind component will remain below 7 kts.
KBUR, Low confidence in TAF. 40% chance CIGs do not develop. 30% chance of IFR CIGs 12-17Z.
06/335 AM.
From Wednesday through Saturday, SCA level NW winds are expected to strengthen each day and will peak Friday afternoon and evening. These winds are likely to reach 20 to 30 kts across the outer waters. There is about a 15% chance of GALE Force winds during this timeframe. SCA level winds are also likely at times across the nearshore waters along the Central coast and into at least western portions of the Santa Barbara Channel.
Short period seas will build during this timeframe especially across the outer waters - reaching 10 feet by Friday then peaking up to 11 feet Friday night through Saturday night.
Ca, NONE. PZ, Small Craft Advisory in effect until 3 AM PDT Thursday for zones 673-676. (See LAXMWWLOX).
