05/1223 PM.
Cloudy, cool, and breezy conditions today will be followed by a warming and drying trend for Wednesday through at least Mother's Day Weekend. There is a chance for widespread high temperatures to be in the 90s Saturday through Monday, with the valley locations generally the warmest.
(tdy-Fri), 05/250 PM.
Partly cloudy to cloudy skies are present across the region with higher ceilings than the typical marine layer low clouds. North to northeast flow will lead to continued cumulus cloud formation and scattered light showers will be possible through this evening, focused over the north facing slopes of the mountains. The low pressure system is continuing to slide to the southeast and as it exits the region, gusty west to northwesterly winds is impacting the coasts through this evening, with the strongest winds (near advisory level) across the Santa Barbara County south coast and the Ventura County Coast.
A pattern shift in the weather pattern will begin Wednesday. Behind the low pressure system, a ridge of high pressure will build, likely peaking in strength Sunday through early next week. Slight warming on Wednesday will be followed by a more significant increase for Thursday and Friday, when highs in the mid 70s to mid 80s will be common. Overnight into morning marine layer clouds will return for some locations tonight and dense fog will be possible Thursday and Friday morning.
(Sat-Tue), 05/252 PM.
Temperatures will continue to trend upwards over the weekend as the ridge strengthens. The ridge will likely peak Sunday through early next week, when 500 mb heights have the potential reach 590-591 dam. This would be in the 99th percentile of 500 mb heights for this time of year. In addition, there is a chance of weak offshore flow from the north (Saturday), shifting northeast (Sunday and Monday). If this flow pattern develops, then it would result in further warming of high temperature across the valleys, and perhaps more impactful, across the beaches (where conditions generally are quite cool in May). Ensemble models and local temperature study data indicate that high temperatures may be widespread in the mid 80s to mid 90s (10-20 degrees above normal), with local 100+ temperatures possible for the warmest valleys. Saturday through Monday look to be the main peak of heat, just right for a very warm Mother's Day weekend. However, a significant heatwave is not guaranteed, if surface pressure gradients end up onshore, as several ensemble models show, heat will be dampened by a seabreeze at the coasts.
05/1705z.
At 15Z at KLAX, there was a deep moist layer up to 8000 ft.
High confidence in VFR TAFs for desert airfields (KPMD & KWJF).
Moderate confidence in remaining TAFs. Patchy MVFR CIGs possible across the LA Basin (06/10Z-18Z) that may affect airfields KSMO, KLAX, & KLGB. 20% chance low clouds do not develop at KPRB. 30% chance CIGs do not develop at KSBP.
For all sites with forecasted CIGs, arrival and clearing times should be accurate within +/- 2 hours.
KLAX, Moderate confidence in TAF. 30% chance MVFR CIGs enter airfield 06/10Z-18Z. Otherwise, VFR conditions are expected. Good confidence that any east wind component will remain less than 5 kts.
KBUR, Moderate confidence in TAF. 30% chance of IFR-MVFR CIGs to develop 10Z-15Z Wed. Otherwise, VFR conditions with no wind issues are expected.
05/216 PM.
Small Craft Advisory (SCA) winds will be common across the Santa Barbara Channel and near the Channel islands this afternoon and evening. These winds will likely reach the nearshore waters especially along the Ventura coastline. Low-end SCA level NW winds are also likely across along the Central coast.
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 SB channel.
Short period seas will build during this timeframe especially across the outer waters - reaching 10 feet by Friday peaking at 11 to 13 feet Friday night through Saturday night.
Ca, NONE. PZ, Small Craft Advisory in effect until 9 PM PDT this evening for zones 645-655-670. (See LAXMWWLOX). Small Craft Advisory in effect until 11 PM PDT this evening for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Thursday for zones 673-676. (See LAXMWWLOX).
