Altadena, CA 91001 Weather

Synopsis

30/248 AM.

Rain chances continue through much of the weekend, with the peak of the rain likely occuring Saturday evening into Sunday morning. Warmer and drier conditions expected next week.

Short term (tdy-sun)

30/800 AM.

***UPDATE***

Latest satellite and surface observations indicate cloudy skies across the area this morning. The moist layer reaches up to over 7000 feet. No significant winds are observed.

Forecast-wise for the immediate short term, no significant issues are expected. With the deep moist layer in place, scattered light showers will continue through the day. Rainfall accumulations, if any, are expected to be less than 0.10 inches although a stray moderate shower could generate a little more. Skies will remain mostly cloudy through the day.

Overall, current forecast has good handle on the immediate short term. So, no significant updates are expected.

***From Previous Discussion***

No major changes to the forecast through the weekend. This has been a challenging system to get a hold of and even more challenging to describe. At this hour (3am) a small area of rain developed just south of Santa Barbara and dropped around a tenth of an inch in about 10 minutes, with the peak intensity at 0.70" per hour. There have been scattered showers elsewhere but generally on the light side.

Expecting this same overall pattern to continue through Saturday afternoon before the main part of the storm moves into the area Saturday evening into Sunday morning. During that period rain should be more steady but generally under a quarter inch per hour and mostly lower than that. Most of the high res models are indicating chances for half inch per hour rates to be 10% or less. And overall rain totals are expected to be higher in LA County and lowest across the northern counties. This is not expected to be a very convective system but can't completely rule out a isolated storm or two, again better chances south.

Showers expected to taper off Sunday morning with most of the rain out of the area by Sunday afternoon.

Long term (mon-thu)

30/412 AM.

Dry and warmer weather expected early next week as a weak high pressure system moves over the area. Some of the models are indicating a Santa Ana pattern but most favor light offshore at most with highs near climatology. Predictability drops off quite a bit mid to late week as models show another upper low over the West but with a lot of uncertainty with the track. Additional rain next week is very unlikely but a cooling trend towards the end of the week seems likely.

Aviation

30/1500Z.

At 15Z at KLAX, there was no inversion or marine layer.

Off and on again MVFR-VFR ceilings and -SHRA expected through Saturday morning. While confidence is low on timing, moderate confidence that most of the period will be VFR and dry with ceilings not lowering to IFR or below.

KLAX: High confidence in ceilings being common through 18Z Saturday, moderate confidence of ceiling not lowering below MVFR, low confidence in timing of -SHRA and MVFR ceilings. East winds likely Saturday 10-17Z, with a 20% chance of reaching 8-10 knots.

KBUR: High confidence in ceilings being common through 18Z Saturday, moderate confidence of ceiling not lowering below MVFR, low confidence in timing of -SHRA and MVFR ceilings.

Marine

30/729 AM.

Moderate confidence in winds and seas staying below Small Craft Advisory (SCA) through Saturday evening, except for a 20% chance of brief gusty downdraft winds with any heavier showers on Saturday. SCA-level NW winds likely to form Saturday Night and Sunday from the Central Coast to San Nicolas Island, including the western Santa Barbara Channel. NE winds under SCA-levels likely to follow on Monday.

Beaches

30/730 AM.

High tides will continue to lower into early next week. The Coastal Flood Advisory will continue through early this afternoon, but as tides lower, impacts should also lower in severity and coverage.

Watches, warnings and advisories

CA: Coastal Flood Advisory in effect until 2 PM PDT this afternoon for zones 87-340-346-349-350-354-362-366. (See LAXCFWLOX). PZ: NONE.