09/127 PM.
A cooling trend will begin today and continue through the weekend. A couple storms will move through the area late Friday through Monday with showers and thunderstorms possible. Dry and warmer weather expected the rest of next week.
(Thu-Sun), 09/944 PM.
***UPDATE***
A couple light showers moved across northern LA county this evening as the first of two upper level low pressure systems moves into the region. Light showers will be possible tonight, mainly for the northern coastal waters and San Luis Obispo County, then spreading south through Los Angeles County during the day on Friday.
***From Previous Discussion***
Two upper lows will move through California Friday through Monday. The first is is just off the northern California coast and generating some showers and thunderstorms there. That upper low is expected to mainly stay in NorCal so impacts with that one will be minimal this far south. Mostly just some light showers Friday afternoon into Saturday morning, more so north of Pt Conception. Can't rule out an isolated storm in SLO County but most of the energy with that system will stay farther north. Rain amounts are expected to remain mostly under a quarter inch.
The second upper low is expected to be the stronger of the two and arriving later Saturday into Sunday morning. This one has much colder air aloft and a better severe weather signature to it with CAPE values approaching 500J/kg, highest north of Pt Conception, but still capable of creating thunderstorms in southern areas as well. Small hail and gusty winds are possible during this period and can't rule out a waterspout or small tornado. Rain amounts with this second system are expected to range from a half to one inch, generally highest north of Pt Conception, though can't rule out some heavy showers even as far south as LA County. Peak rain rates expected to range from 0.25-0.50" per hour with isolated stronger storms as high as 0.75" per hour.
Several inches of snow are possible above 7000 feet, then lowering Sunday night as the upper low moves through.
(Mon-Thu), 09/227 PM.
The upper low is expected to pass through southern California Monday morning, with scattered showers and snow levels dropping to around 4500-5000 feet. Chances for any snow accumulations on the Grapevine are less than 10% but there could be some flurries or mix of rain and snow on the summit Monday morning. There is a chance of showers across LA County through Monday afternoon if the low is a little slower leaving the area. Otherwise, drying conditions expected Monday night and dry and warmer weather the rest of the week.
10/0243z.
At 0022Z at KLAX, the marine layer was 1200 ft deep. The top of the inversion was at 3700 ft with a temperature of 16 C.
Overall, moderate confidence in 00Z TAF Package. Timing of flight cat changes may be off +/- 2 hours and cig hgts by +/- 300 ft. PROB30 -SHRA chances after 14/17Z for KPRB, KSBP, and KSMX.
KLAX, Moderate confidence in TAF. Low clouds could arrive as early as 09Z or as late at 13Z. Cigs could range between 008 and 015. No significant east wind component expected.
KBUR, Moderate confidence in TAF. There is a 30-40% chance for IFR conditions before 12Z.
09/920 PM.
Current Small Craft Advisories are on track. Refer to MWWLOX and CWFLOX for more details.
A weak Cold Front will move across the coastal waters Friday into Saturday morning bringing showers and a slight chance for a thunderstorm north of Point Conception.
A second system will arrive later on Saturday into Sunday with a more traditional cold front. This stronger front will bring numerous showers and a slight chance for thunderstorms across all waters. Potential hazards include: heavy downpours, dangerous cloud to ocean lightning, small hail, and erratic gusty winds. Boaters, especially those with small vessels should avoid these conditions.
Ca, NONE. PZ, Small Craft Advisory in effect until 11 PM PDT this evening for zone 650. (See LAXMWWLOX).
