03/239 AM.
Significant warming is expected today through Sunday as gusty Santa Ana winds return. Winds will be strongest Friday and Saturday across Los Angeles and Ventura Counties. A cooling trend will begin Monday with temperatures back to near normal around mid week.
(tdy-Sun), 03/844 AM.
***UPDATE***
Pressure gradients have turned sharply offshore this morning but winds have been slow to migrate below 2000 feet. This should happen before 11am this morning with widespread Santa Ana winds across the usual favored areas of LA/Ventura Counties. Temperatures will be warming up rapidly as well with most areas in the upper 70s and 80s this afternoon.
***From Previous Discussion***
A sharp reversal of the E/W gradient from 5mb onshore to almost 5mb onshore is currently taking place. This strong a trend almost always leads to a stronger wind response. This rapid switch in combination with a an increasing offshore push from the north (1 mb to 4 mb) will bring a moderate Santa Ana wind event to the region including the Santa Lucia range in the Central Coast. Wind advisories are in effect for these areas for widespread 30-50 mph wind gusts. There will be local gusts to 60 mph across the ridgetops of the LA/Ventura Mountains, including the western Santa Monicas. The offshore flow will combine with rising hgts from an approaching ridge to bring 8 to 12 degrees of warming to the csts and vlys and 4 to 8 degrees across the mtns and far interior. Most cst/vly highs today will end up in the mid 70s to lower 80s or about 8 degrees over normal.
Saturday will be much like today except the gradients will be a little weaker and the upper support less. So while there will be advisory level gusts in the morning they will be more of the low end 35-45 mph variety. Temperatures will be the main talking point with an additional 3 to 6 degrees of warming bring cst/vly maxes up into the 80s with a few 90 degree reading not out of the question.
There will be offshore flow in the morning Sunday but at only around a single mb both from the N and E it will only produce local sub advisory gusts. The gradients will actually turn onshore in the afternoon and this will bring an earlier and stronger seabreeze to the csts/vlys which will experience 3 to 6 degrees of cooling. Further airmass warming will lead to and additional 2 to 4 degrees of warming for the mtns and far interior. Max temps will end up about 12 degrees above normal.
(Mon-Thu), 03/237 AM.
On Monday the ridge flattens out and onshore flow returns. Its likely that marine layer stratus will return to the coasts and some of the lower vlys. The marine layer and strong onshore flow will knock 5 to 10 degrees off of the max temps across the csts and vlys.
Slight offshore trends will lead to a little less marine layer and 1 or 2 degrees of warming on Tuesday.
On Wednesday the ridge will flatten further as a trof approaches from the west. Onshore flow will increase as will the clouds as mid levels moisture streams in. Max temps nose dive 3 to 6 locally 8 degrees and will end up in the upper 60s and 70s across the csts/vlys.
The mdls and ensembles are all over the place on the Thursday and Friday forecast. There is a consensus that some energy will arrive but the amount and location and timing differs greatly. Most solutions show low amounts but there are a few solutions that are over a half inch. Right now the fcst eases into it with cloudy and cooler days with a slight chc of light rain. This fcst will surely evolve over the course of time.
03/1507z.
At 1530Z at KLAX, there was no marine layer or marine inversion.
Overall for the 18Z TAF package, high confidence in VFR conditions through the period as a SCT-BKN200 foot deck drifts overhead. Northeasterly winds are expected across the area, especially KOXR, KCMA, KBUR and KVNY. Light LLWS and wind shear will be likely across the foothills and mountains.
KLAX, High confidence in 18Z TAF as VFR conditions are expected through the period. There is a 10% chance of an easterly wind component near 8 knots 15Z-21Z Saturday.
KBUR, High confidence in 18Z TAF as VFR conditions are expected through the period. Ocnl light LLWS and turbulence around the airfield through 22Z.
03/807 AM.
For the Outer Waters, moderate to high confidence in current forecast. Through this afternoon, high confidence in Small Craft Advisory (SCA) level seas, mainly across PZZ670/673. From this evening through Sunday, high confidence in winds and seas remaining below SCA levels. For Monday through Tuesday, there is a 50-70% chance of SCA level winds, especially over the southern zones from west of Point Conception down to San Nicolas Island (PZZ673-676).
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Today through Monday, high confidence in winds and seas remaining below SCA levels. On Tuesday, there is a 50% chance of SCA level winds in the afternoon and evening hours.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. High confidence in SCA level northeast winds from Ventura south to Santa Monica today, with winds remaining below SCA levels elsewhere. For tonight and Saturday, there is a 50-70% chance of SCA level northeast winds from Ventura south to Santa Monica. For Sunday and Monday, high confidence in winds and seas remaining below SCA levels. On Tuesday, there is a 50-70% chance of SCA level W-NW winds, mainly across western portions.
Ca, Wind Advisory remains in effect until 2 PM PDT this afternoon for zones 88-342-354-355-358-371-372-374. (See LAXNPWLOX). High Wind Warning remains in effect until 6 PM PDT this evening for zones 369-375-379. (See LAXNPWLOX). Wind Advisory remains in effect until 6 PM PDT this evening for zone 380. (See LAXNPWLOX). PZ, Small Craft Advisory in effect until 3 PM PDT this afternoon for zones 650-655-670-673. (See LAXMWWLOX).
