06/455 PM.
A warming and drying trend will continue into early next week. Temperatures will reach the mid 70s to 80s across much of the region through Friday, then high temperatures in the 80s and 90s will be common over the weekend through Tuesday. There is a chance for 100 degree readings in the warmest valleys during peak of the heat, which will be on Mothers Day and Monday.
(Wed-Sat), 06/831 PM.
***UPDATE***
It was a mostly sunny day today, with high temperatures in the high 70s to mid 80s across the warmest valleys and the 60s and 70s elsewhere. Looking at current satellite imagery as well as most recent models, decided to remove low clouds and fog from Malibu to Point Conception during the overnight into early morning hours tonight. Thus, for the Los Angeles coast south of Malibu, as well as the Central Coast, the forecast still has low clouds and fog moving in overnight. However, despite the change to the forecast, there is still a 30% chance of clouds moving into the Ventura Coast, and a 20% chance for the Santa Barbara coast overnight.
As for winds, north to northwest winds have started to pick up across the Santa Barbara Southwest Coast, Western Santa Ynez range, and the I-5 Corridor. Local advisory level gusts are expected, mainly for the Santa Barbara Sundowners overnight tonight.
Looking ahead to tomorrow, high temps will warm up about 5 degrees, bringing highs into 70s and 80s, with a few 90s possible for the warmest locations. Sundowner and I-5 north to northwesterly winds will resurface in the late afternoon to overnight hours. However, Thursday night looks stronger than tonight with a SBA-SMX sfc pressure gradient of -3.0 mb (compared to -2.5 mb tonight) and an advisory will possibly be needed for the Santa Barbara Southwest coast/Western Santa Ynez Range Thursday night.
Otherwise, forecast is on track and no other updates were needed.
***From Previous Discussion***
Mostly sunny skies and calm pleasant weather is expected for today behind the low pressure system that moved through the area yesterday. Over the next several days, 500 mb heights will increase sharply as a ridge of high pressure sets up over the region. As a result, warming is expected for Thursday and Friday, bumping highs into the mid 70s to mid 80s across much of the region. Weak offshore flow in the afternoon will minimize the seabreeze at the coast allowing for warm conditions even across most beaches, though the valleys will still be the warmest locations.
This evening through tonight, gusty northwest winds will impact southwestern Santa Barbara County and the Interstate 5 Corridor, due to a north-to-south surface pressure gradient. These winds will redevelop again on Thursday.
Marine layer clouds are favored to return late tonight into tomorrow morning across portions of the coasts and valleys, however there is around a 30 chance that skies will be mostly clear tomorrow morning (like they were this morning). Tomorrow night through Friday morning, surface pressure gradients will likely be more favorable for the coasts, and building high pressure will increase the risk for dense fog.
(Sun-Wed), 06/238 PM.
The ridge of high pressure will continue to build, likely peaking in strength on Mothers Day (Sunday) and Monday and lingering into mid next week. 500mb heights are expected to reach 590dam, which is between the 97th and 99th percentiles for this time of year over are the region, indicative of a fairly rare event for May. Mothers Day and Monday be the hottest days of the heat spell, with most temperatures in the valleys and deserts in the 90s, and there is the potential for temperatures as high as 100 degrees across the western San Fernando Valley and the interior valleys of San Luis Obispo County. Maximum temperatures will be at least 10-15 degrees above normal, with areas locally 20+ degrees above normal. Heat Advisories will be possible for this event, right now around a 30 percent chance. This will depend a lot on how the surface pressure gradients play out, as they have the potential to be lightly offshore (warmer temperatures especially at the coasts) or more onshore (cooler at the coasts). Overall prepare for a warm weekend through early next week, and consider the minor to moderate HeatRisk when planning any outdoor activities, including for Mother's Day.
07/0244z.
At 2308Z at KLAX, the marine layer was 1400 ft deep. The top of the inversion was around 3700 ft with a temperature of 18 C.
High confidence in 00Z TAFs for KPMD and KWJF, and valley sites. Moderate to low confidence in remaining sites due to uncertainty in marine layer clouds. LIFR CIGs possible at KSMX from 06Z-15Z (60%) and KSBP from 07Z-12Z (30%). There is a 20% chance for brief cigs at KLGB and KLAX.
KLAX, Moderate confidence in TAF. 20% chance CIGs around BKN006 from 12Z-15Z. Otherwise, VFR conditions are expected. No significant east wind component expected.
KBUR, High confidence in TAF. VFR conditions with no wind issues are expected.
06/1021 PM.
SCA level NW winds are expected to strengthen each day through Saturday for the outer waters. Winds may approach Gale Force Friday, with a better chance (30%) for Gale Force winds Saturday afternoon and evening. SCA level winds are also likely during the evening hours across the nearshore waters along the Central coast and into at least western portions of the Santa Barbara Channel and near the Channel Islands through Saturday.
Short period seas will build during this timeframe especially across the outer waters - reaching around 10 feet Friday 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 until 1 AM PDT Thursday for zones 645-650. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Friday for zones 670-673-676. (See LAXMWWLOX).
