03/851 AM.
Temperatures will be slightly above normal inland and near normal along the coast through Friday, then dropping below normal over the weekend and into next week as a large low pressure system develops over the West coast. Skies will be mostly clear except for night and morning low clouds and fog across the coast and valley areas.
(tdy-Fri), 03/912 AM.
***UPDATE***
The marine layer has risen to 2200 feet this morning, covering all the coast and coastal valleys. Expecting similar clearing as yesterday as well as similar afternoon temperatures. Then some gusty northwest winds across southwest Santa Barbara County this evening and possibly the I5 corridor.
Not much change expected Thursday, then turning cooler Friday and through the weekend with a large upper low approaching.
***From Previous Discussion***
A 1600 ft deep marine layer, onshore flow and a weak eddy have all teamed up to bring low clouds much of the csts and some of the vlys. At the same time a ridge is nosing into the middle of the state from the north and in addition to creating rising hgts it is also bring northerly flow to the area. This northerly flow will bring an earlier clearing of the low clouds to many areas this morning. The sunny afternoon skies, northerly flow and rising hgts will bring 3 to 6 locally 8 degrees of warming to all areas today. Vly temps will reach the mid 80s to lower 90s this afternoon or 3 to 6 degrees above normal.
The northerly flow will peak tonight and advisory level gusts are likely (70-80 percent chc) across the western portion of the SBA south cst and portions of the I-5 corridor.
There is a fairly tricky low cloud forecast Thursday morning as a decently strong eddy competes with the offshore flow from the north. The eddy will likely bring low clouds to the coasts of LA and VTA counties and portions of western SBA county. The north flow, however, will keep the vlys, the SBA south coast and SLO county cloud free. Max temps will not change much with all areas experiencing above normal temps save for the beaches which will end up a few degrees under normals due to the strong onshore flow in the afternoon.
No eddy is forecast for Friday morning and there will not be enough oomph to lift the low clouds into the vlys. Onshore flow to the north and east will allow low clouds to cover most if not all of the coastal areas. The ridge breaks down and this along with the strong afternoon onshore flow will cool most areas by 2 to 4 degrees.
(Sat-Tue), 03/236 AM.
Troffing and mdt-stg onshore flow will dominate the xtnd period. This will bring very June like conditions to the area on all 4 days. Onshore flow will be strongest over the weekend and the low clouds will penetrate deep into the vlys and will likely not clear at all from many beach and nearshore areas while the rest of the csts/vlys see slower than normal clearing. 3 to 5 degrees of cooling Saturday will be followed by 1 to 3 additional degrees on Sunday. Sunday's max temps will end up in the upper 60s to mid 70s across the csts and a degree or 2 either side of 80 in the vlys. These max temps are mostly 2 to 4 degrees blo normal.
The onshore flow relaxes some on Mon and Tue and this will bring earlier clearing times for the marine layer stratus as well as a few degrees of warming each day.
03/1710z.
At 1700Z at KLAX, the marine layer was 1900 feet deep. The top of the inversion was near 4200 feet with a temperature of 23 degrees Celsius.
For 18Z TAF package, high confidence in forecasts for KPRB, KWJF and KPMD with VFR conditions expected.
For all other TAFs, moderate confidence in current forecasts. Timing of flight category changes could be +/- 3 hours of current forecasts.
KLAX, Moderate confidence in 18Z TAF. Timing of return of CIG/VSBY restrictions could be +/- 3 hours of current 08Z forecast. There is a 30% chance that CIGs could return at MVFR levels tonight. No significant easterly wind component is expected.
KBUR, Moderate confidence in 18Z TAF. There is a 20-30% chance of IFR CIGs in the 08Z-16Z time frame.
03/720 AM.
For the Outer Waters, moderate to high confidence in current forecast. Through Thursday morning, high confidence in winds increasing to GALE force levels and GALE WARNINGS will remain in effect. From Thursday afternoon through Sunday, high confidence in combination of Small Craft Advisory (SCA) level winds and seas (peaking 12-15 feet) with a 20-30% chance of Gale force winds at times.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Through tonight, there is a 60-80% chance of GALE force winds and a GALE WARNING remains in effect through this evening. For Thursday through Sunday, there is a 60-80% chance of SCA level winds in the afternoon and evening hours. Additionally, there is a 30-40% chance of SCA level seas at times.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. For a majority of the southern Inner Waters, high confidence in winds and seas remaining below SCA levels through Sunday. The only exception will be the western half of the Santa Barbara Channel where there is a 30-40% chance of SCA level winds this evening and overnight and a 20-30% chance on Saturday and Sunday.
Ca, NONE. PZ, Gale Warning in effect until 11 PM PDT this evening for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect from 11 PM this evening to 9 PM PDT Thursday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until noon PDT today for zones 670-673. (See LAXMWWLOX). Gale Warning in effect until 9 AM PDT Thursday for zones 670-673. (See LAXMWWLOX). Small Craft Advisory in effect from 9 AM to 9 PM PDT Thursday for zones 670-673-676. (See LAXMWWLOX). Small Craft Advisory in effect until 6 PM PDT this evening for zone 676. (See LAXMWWLOX). Gale Warning in effect from 6 PM this evening to 9 AM PDT Thursday for zone 676. (See LAXMWWLOX).
