28/519 PM.
Dry weather will continue at least through next Tuesday. A cooling trend will continue through the weekend as onshore flow returns. Gusty Santa Ana winds are possible Monday with warmer temperatures. Then turning cooler Tuesday followed by a chance of rain Wednesday.
(Fri-Mon), 28/825 PM.
***UPDATE***
A significant drop in temperatures was observed today across the coasts and valleys, with most highs in the low to mid 70s. The current marine layer depth at LAX is around 900 feet. Low clouds and fog are likely to become widespread across the coasts and coastal plains tonight into tomorrow morning, with chances for patchy dense fog.
***From Previous Discussion***
Light onshore flow has returned and temperatures have adjusted accordingly. Coast and valleys are 5-15 degrees cooler and the Antelope Valley is 10-15 degrees warmer. The marine layer will deepen slightly tonight and may sneak into some of the lower coastal valleys later on. A little more cooling most areas as well but still near to slightly above normal. Sunday should be almost a carbon copy of Saturday.
Ensemble models continue to strongly favor at least a light to moderate Santa Ana pattern Monday and now the deterministic models are starting to catch on. The NAM is forecasting a -5.1mb LAX/DAG gradient Monday morning and the ensembles have been inching closer to the 6mb range. The big difference with this event is temps aloft are much colder so highs will be at least 10 degrees cooler than with the most recent Santa Ana. Current forecast highs are likely a little too cool for coast and valleys which is common a few days out. If the pattern holds tomorrow and the NBM isn't catching on then highs will likely need to be adjusted upward at least 5 degrees. Given the gradients and better support aloft to the tune of 40kt at 950mb this event will more than likely generate some advisory level winds Monday across the usual Santa Ana favored areas of LA/Ventura Counties and possibly the Santa Lucias as well.
(Tue-Fri), 28/128 PM.
Monday's Santa Ana event will quickly shift back onshore Tuesday and could see some patchy dense fog reaching the beaches. Otherwise, a quiet day with temperatures near normal with generally sunny skies.
There is a chance of light rain across the area Wednesday as another inside slider trough drops into the Great Basin. Ensemble solutions are still exhibiting a wide range of possibilities but at least half of the solutions indicate some light rain developing. It could also be dry with some light offshore winds, but the trends favor the light rain scenario. Most of the solutions show rain amounts under a half inch, and mostly under a quarter inch.
Most of the ensembles show rain ending Wednesday night but there area a few ensembles that keep the upper low close by with lingering showers into Thursday. Most, though favor a dry day Thursday and Friday with warming temperatures.
29/0118z.
At 0009Z at KLAX, the marine layer was 600 ft deep. The top of the inversion was near 1500 ft with a temperature of 18 C.
High confidence in VFR TAFs for KPMD & KWJF.
Low confidence in the coastal TAFs and low to moderate confidence in the valley TAFs. The timing of CIG/VSBY restrictions may be off by at least +/- 3 hours and flight cats may be off by one or two when restrictions are present.
There is a 30% chance of V/LIFR conditions at KPRB from 13Z to 17Z Sat. 20-30% chance of LIFR CIGs at KSMX from 10Z to 16Z Sat. Low confidence for KSBA where arrival of CIGs could be off +/- 4 hours with a 30% CIGs do not arrive or remain intermittent in nature. KBUR and KVNY have a 20-30% chance of IFR or lower conds between 08Z to 16Z Sat.
KLAX, Low to moderate confidence in the 00Z TAF. Arrival of IFR CIGs 005-009 with 3SM to 4SM VSBYs may be off +/- 3 hours from forecast of 06Z. 10-20% chance conds drop to LIFR overnight. Moderate confidence in VFR conditions to return after 16Z Sat. No significant east wind component expected.
KBUR, Low to moderate confidence in the 00Z TAF. There is a 20-30% chance of IFR to LIFR conditions from 08Z to 16Z Sat.
28/822 PM.
A coastal jet is currently impacting the northern outer waters with Small Craft Advisory (SCA) winds. Although Seas are below SCA levels currently, there will be borderline SCA seas possible 30NM from the Central coast Shoreline (PZZ670). SCA wind gusts are also affecting PZZ673 and should continue through 3 AM Saturday. At that point, SCA winds and seas will end across the outer waters. Then, conditions will struggle to meet SCA criteria even beyond 30NM from shore through Sunday morning. Chances do increase Sunday afternoon and evening, but still looks unimpressive and borderline at best. Conditions are expected to remain below SCA levels across all inner waters through the weekend.
Low to moderate chances for borderline SCA conditions across the Outer Waters beyond 30NM from shore and low to very low chances elsewhere across coastal waters Monday through Wednesday. Weak offshore winds will affect the waters nearshore from Ventura to Malibu on Monday. Low confidence in another round of offshore winds on Wednesday.
Ca, NONE. PZ, Small Craft Advisory in effect until 3 AM PST Saturday for zones 670-673. (See LAXMWWLOX).
