22/1154 PM.
Warmer than normal conditions are expected to persist through the week, peaking on Tuesday. Low clouds and dense fog will continue to impact some coastal areas each night and morning. Also, there will be some gusty northerly winds across the mountains through the week.
(tdy-Wed), 23/1217 AM.
Srn CA will be sandwiched between fast moving WSW flow to the north and large 590 dam upper high to the SE. Hgts will be near 587 dam today and Tue, but will fall a few dam on Wednesday as a weak and dry trof moves into the area. At the sfc both the N/S and E/W gradients will follow a typical diurnal curve. The E/W gradient will oscillate from weak onshore flow in the morning to moderate onshore flow in the afternoon. The N/S gradients will be weakly offshore in the morning and weakly onshore in the afternoon.
The weak offshore push from the N will not be strong enough to prevent low clouds from moving in each night. The strong capping inversion and moderate onshore push to the east will mean clearing times will be later than usual and arrival times will be earlier. The high hgts will smoosh the marine layer to under a 1000 ft and bring pockets of dense fog to the coastal areas. There is better offshore flow N of Pt Conception and this should keep most of the low clouds away although western SBA county may see some areas of morning low clouds.
Gusty advisory level northerly winds are also expected today and tonight, mainly affecting the I-5 Corridor and the western Antelope Valley Foothills with gusts 45 to 55 mph. Gusty west to north winds are then expected at times through Thursday.
Look for a big jump in temps today across the csts and vlys. South of Pt Conception there will be 5 to 10 degrees of warming with less confidence across the nearshore area where the marine air could limit warming to only 1 or 2 degrees) for csts/vlys south of Pt Conception. The stronger NE flow N of Pt Conception will bring 15 to 20 degrees of warming. Cooler air moving in from the San Joaquin Vly will lead to a few degrees of cooling across the far interior. Looks for a degree or 2 of warming for most areas on Tuesday making it the warmest day of the next 7. The lowering hgts on Wednesday will bring a couple of degrees of cooling to the area with the Central Coast cooling about 6 degrees as the offshore flow weakens there.
South of Pt Conception the beaches will see 70s, the rest of the csts 80s and the vlys will see max temps in the upper 80s and lower 90s today. These temps will general not change much Tue and Wed. North of Pt Conception, the Central Coast and the Santa Ynez vly will see max temps a degree or 2 either side of 90. HEAT ADVISORIES are in effect for this area through 800pm on Tuesday.
(Thu-Sun), 23/250 AM.
Benign but warmer than normal weather will persist through the xtnd period. The upper level high to the SW will strengthen and push back into Srn CA on Thu/Fri over the weekend weak troffing will move into the state and knock the ridge down some. At the sfc the same diurnal trends will continue with weak to moderate onshore flow in the E/W direction and weak offshore followed by weak onshore flow in the N/S direction.
There will not be too much change from Wed on Thu/Fri. Look for night through morning low clouds and patchy dense fog. Max temps will not change much day to day with 70s at the beaches, 80s further inland and lower 90s in the vlys.
There will be more marine layer and cooler temps over the weekend as the trof passes overhead and onshore flow increases a touch. Most areas will likely have 1 to 2 degrees of cooling each day. By Sunday max temps will mostly be in the 70s and lower 80s at the csts and in the mid to upper 80s in the vlys. Despite the cooling max temps Sunday will end up 8 to 12 locally 15 degrees above normal.
Things still look dry through almost the end of the month. Both AI mdls are now converging on a rain event sometime in the 31st to 1st time frame. This storm will most likely produce about a half inch of rain with a 20 percent chc of an inch. The EC-AI goes on to show another system around the 6th of April.
***OF NOTE***
This has be a phenomenally warm month. Using the forecasted high temperatures for DTLA for today (the 23rd) to the 31st along with the max temps that have already occurred, the DTLA average max temp for the month would be 83.5 degrees. This would handily eclipse the previous record holders:
79.1 degrees in 2015 76.7 degrees in 2017 76.0 degrees in 1931 75.8 degrees in 1934 75.7 degrees in 1959
23/0951z.
At 0835Z at KLAX, the marine layer was 600 feet deep. The top of the inversion was at 1600 feet with a temperature of 23 C.
Moderate confidence for coastal TAFs SBA and south including KLAX. There is a 25 percent chc of no VLIFR conds. VFR conds may not arrive until a hour after fcst.
Low confidence for KBUR, KVNY, and KSMX with a 40 percent chance of IFR or lower cigs vsbys 12Z-16Z.
KLAX, Moderate confidence in TAF. There is 25 percent chc of 1/4SM FG VV002 conds 12Z-16Z. VFR conds may not arrive until 19Z. IFR/LIFR conds may return as early as 01Z. No significant easterly wind component is expected.
KBUR, Low confidence in TAF through 17Z with a 40 percent chc of 1/4SM FG VV002 conds 12Z-17Z. Good confidence aft 17Z.
22/924 PM.
For the Outer Waters, moderate to high confidence in current forecast. Through Thursday, high confidence in a combination of Small Craft Advisory (SCA) level winds and seas. Wednesday, there is a moderate chance of GALES, likely to be focused during the afternoon thru overnight timeframe, and across western portions. Large seas of 10-14 feet are possible late Wednesday through early Friday.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Through Thursday, there is a 50-70% chance of SCA level winds during the afternoon and evening hours.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. For most of the southern Inner Waters, high confidence in winds and seas remaining below SCA levels through Thursday. The only exception will be the western half of the Santa Barbara Channel where there is a 20-30% chance of SCA level winds through Thursday, focused during the afternoon and evening hours.
Dense fog is possible this week, focused in the late evening to early afternoon hours each day. Visibilities of one nautical mile or less can be expected.
Ca, Heat Advisory remains in effect from 10 AM this morning to 8 PM PDT Tuesday for zones 340>342-346>348. (See LAXNPWLOX). Wind Advisory remains in effect until 3 AM PDT Tuesday for zones 378-381. (See LAXNPWLOX). PZ, Small Craft Advisory in effect from 3 PM this afternoon to 9 PM PDT this evening for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Tuesday for zones 670-673-676. (See LAXMWWLOX).
