05/1251 AM.
Onshore flow will continue to bring low clouds to the coasts and coastal valleys each night through morning. Onshore flow will start to weaken Monday and cause decreasing clouds in the valleys and gradually warming temperatures. Expect a return to above normal temperatures early this week.
(tdy-Tue), 05/221 AM.
The high clouds streaming over the area disrupted the marine layer early this morning, resulting in fewer coastal low clouds across the coasts and coastal valleys. These high clouds should diminish throughout the day. The combination of the decreasing high clouds and increase in onshore flow will lead to night through morning Marine Layer clouds reestablishing tonight into Monday morning. However, lingering mid-level moisture this evening and tonight may cause the marine layer to be patchy across the coasts and valleys. Starting Monday night, higher confidence in a return of night through morning clouds each day through the week, however combined with high pressure building aloft, the clouds will lessen in extent each night
As for temperatures, expecting a slight cool-down today due to slightly lower heights aloft than on Saturday and the aforementioned increasing onshore flow. This will be followed by warming Monday and especially Tuesday through Thursday with strong high pressure building aloft and weakening onshore flow. Highs in the 80s to mid 90s are expected away from the coast today, rising into the mid 80s to low 90s, with the warmest valleys reaching a few degrees on either side of 100 degrees starting Tuesday. Some heat advisories may be needed by Tuesday, and will be likely for Wednesday and Thursday.
Through Monday, onshore winds gusting up to 35 mph are expected for the Antelope Valley and Foothills, along with Sundowner winds each evening tonight through Wednesday, with peak gusts up to 40 mph.
(Wed-Sat), 05/232 AM.
Above normal temperatures and dry weather are anticipated through the extended period as high pressure continues to strengthen aloft. Make sure to drink plenty of hydrating fluids, check on those sensitive to heat and/or without air conditioner, and never leave anyone in a car without air-conditioning as lethal temperatures can be reached inside a car within a matter of minutes.
At this point, the upper level ridge looks to be centered across southern California over the Wednesday/Thursday time period, when afternoon temperatures should peak. The ridge is then expected to shift north and east by the end of the week and over next weekend, providing some minor relief to end the week. That said, temperatures are still expected to remain near or above normal through next weekend, and likely beyond - with CPC outlooks continuing to favor above normal temperatures through at least week 2.
Given the anticipated warm up, there will be at least a minor to moderate heat risk each day. As mentioned in the short- term discussion, heat advisories will eventually become necessary Tuesday-Thursday, mainly across inland areas including the San Fernando and Santa Clarita valleys.
05/0700z.
At 0511Z at KLAX, the marine layer was 1100 ft deep. The top of the inversion was 20000 ft deep with a temperature of 23 C.
High confidence in VFR TAFs for desert airfields (KWJF & KPMD).
Moderate confidence in remainder of TAFs. Timing of flight cat changes may be off by +/- 2 hours and CIG heights +/- 300 ft.
KLAX, Moderate confidence in TAF. Arrival and clearing times of 008-010 CIGs may be off +/- 3 hours. No significant easterly wind component expected.
KBUR, Moderate to high confidence in TAF. There is a 15% chance of BKN005-010 05/11Z-15Z.
05/154 AM.
For the Outer Waters, moderate to high confidence remains for the current forecast. High confidence in winds and seas remaining below Small Craft Advisory (SCA) levels through this morning. For this afternoon through Thursday, there is a greater than 80% chance of SCA level winds. Additionally, there is a 20% chance of Gale Force wind gusts around the Channel Islands late Tuesday afternoon into evening, and across all the outer waters on Wednesday. Seas will gradually increase to advisory levels by this evening, and start to subside Thursday night into Friday.
For the Inner Water north of Point Conception, moderate to high confidence in current forecast. Winds and seas are expected to remain below SCA levels through Monday morning. There is a 40% chance of SCA level winds on Monday, 70% chance Tuesday & Wednesday, and a 60% chance on Thursday. Seas will gradually increase to advisory levels by this evening, and start to subside Thursday night into Friday.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. High confidence in winds and seas remaining below SCA levels through this morning. There is a 40% chance of SCA level winds across the Western portion of the Santa Barbara Channel this afternoon and evening, increasing to 80% chance each afternoon/evening through Wednesday thereafter. Local gusts could approach 21 kts during the late afternoon through evening hours near Point Dume and across the San Pedro Channel.
Ca, NONE. PZ, Small Craft Advisory in effect from 5 PM Monday to 5 AM PDT Tuesday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect from 5 PM this afternoon to 5 AM PDT Tuesday for zones 673-676. (See LAXMWWLOX).
