13/109 PM.
A large storm system will move into the Central Coast this afternoon and will continue further south tonight into Friday. The storm will generate periods of moderate to heavy rain this evening through Saturday, and possibly into early next week. Flooding of roadways and burn scars is possible, especially Friday and Saturday.
(Thu-Sun), 13/910 PM.
, AT LEAST 3-6 INCHES OF RAIN ACROSS THE AREA WITH MAJOR IMPACTS MAINLY FRIDAY AND SATURDAY, INCLUDING POTENTIAL FOR DANGEROUS FLOODING AND DEBRIS FLOWS,
Confidence is increasing that a major storm system will impact the area with periods of heavy rain tonight through Saturday due to a slow moving system that is cutting off from the jet stream and has PW's approaching 1.5" which is extremely high for this time of year. This has been a complicated system but computer projections continue to indicate two distinct periods of rain moving through the area. The first being tonight into Friday morning, most impactful west of LA County and heaviest across southern Santa Barbara County and the Ventura County mountains where 3 to 4 inches of rain is possible with rain rates between a half and one inch per hour. Current radar Margery as of 830 pm this evening already showing areas of light to moderate rain across Santa Barbara and San Luis Obispo counties, with lighter shower activity across Ventura and LA counties. During the past 30 minutes, rainfall rates have increased to one quarter to one half inch per hour across western portions of San Luis Obispo and Santa Barbara counties, and are expected to increase during the next few hours. This has resulted in the issuance of a flood advisory for these areas, with roadway flooding likely becoming more common through the night. The northern portions of the Santa Lucia Mountains could also see around 3 inches of rain through tonight. Isolated thunderstorms are possible as well that will contribute to the higher rain rates but no severe weather is expected with this first impulse.
The first band of rain will slowly shift into eastern Ventura county and LA County Friday and Friday night but rain rates are expected to decrease as the this band moves farther away from the main upper low and into less unstable air. Not expecting any significant issues other than some wet roadways during this period.
The second part of the storm Saturday into Saturday night has the potential to be the most significant, though there is also much more uncertainty with it due to the upper low being cutoff. A majority of the ensemble solutions do show an additional 1-3 inches of rain falling as the main upper low pivots towards the the coast, though it's worth noting that there are roughly 10% of the solutions that show as much as an additional 3-5 inches of rain. Forecast soundings from Santa Maria to Long Beach indicate favorable profiles for thunderstorms and severe weather, which would include a small chance of weak tornados, strong and gusty winds, very heavy rain (possibly even locally exceeding one inch per hour), and hail. The ultimate path of the upper low will likely determine if and where these occur but for now they are all in play for all areas. For now, Flood Watches have been issued for everywhere south of SLO County except for the Cuyama Valley. In evening update, have also included Catalina Island and Channel Islands into the Flood Watch.
There will be breaks in the rainfall, sometimes for several hours and rainfall is expected to taper off by later Saturday night, assuming the upper low behaves and moves into Nevada Sunday afternoon. Rain chances continue in the forecast through Sunday as many of the ensembles maintain enough low level moisture and instability to trigger some light precip but there should be no significant impacts after early Sunday morning.
(Mon-Thu), 13/222 PM.
The rainy pattern is expected to continue into early next week as models indicate a much weaker system arriving Monday with amounts mostly under a half inch. Can't rule out some light showers continuing into Tuesday as the upper low moves east but lingering moisture remains.
Good confidence that there will be little day to day changes in the temperatures. Max temps will mostly be in the lower to mid 60s across the csts/vlys which is 6 to 12 degrees blo normals.
14/0242z.
Around 00Z at KLAX, the was a deep moist layer up to at least 4000 ft.
High confidence in rain impacting all sites through the period. However, low confidence in timing the of rain, and associated CIG and VSBY restrictions, could be +/- 4 hours of current forecasts. Expect mostly IFR to MVFR cigs for much of the period. Additionally low confidence in winds, as they may be gusty and change directions quickly due to a frontal passage. Winds will be south- southeast during most peak speeds.
There is a 10-20% chance of thunderstorms from KSBA northward in until around 12Z Fri time frame. After 12Z, there will be a 10-20% Chance of thunderstorms south of Point Conception. Any thunderstorms that develop will be capable of producing frequent lightning, brief heavy rain and gusty/erratic winds.
KLAX, Low confidence in timing the of rain, and associated CIG and VSBY restrictions, could be +/- 4 hours of current forecasts. Winds will shift to an easterly direction around 04Z-07Z, with high confidence in easterly winds above 8 knots in the 08Z-20Z time frame.
KBUR, Low confidence in timing the of rain, and associated CIG and VSBY restrictions, could be +/- 4 hours of current forecasts.
13/151 PM.
For the Outer Waters, moderate to high confidence in current forecast. Today through Saturday, high confidence in combination of Small Craft Advisory (SCA) level winds and seas for all of the Outer Waters. Additionally, there is a 60-80% chance of Gale force southeasterly winds through this evening. On Sunday, high confidence in winds and seas remaining below SCA levels. For Monday through Tuesday, there is a 70-90% chance of a combination of SCA level winds and seas.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Today through Friday night, high confidence in a combination of SCA level winds and seas. Additionally, there is a 50-60% chance of Gale force winds through this evening. For Saturday and Sunday, high confidence in winds and seas remaining below SCA levels. For Monday and Tuesday, there is a 60-80% chance of a combination of SCA level winds and seas.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Today through Friday night, there is a 60-80% chance of SCA level winds across the Santa Barbara Channel with winds and seas remaining below SCA levels elsewhere. For Saturday, there is a 50-70% chance of SCA level southeasterly winds. On Sunday, high confidence in winds and seas remaining below SCA levels. For Monday through Tuesday, there is a 60-80% chance of SCA level winds.
There is a 10-20% chance of thunderstorms across the coastal waters through Saturday night. For tonight and Friday morning, the thunderstorm threat will exist from around Point Conception northward. For Friday night through Saturday night, the chances for thunderstorms will shift to the coastal waters south of Point Conception. Any thunderstorms that develop would be capable of producing brief heavy rain, gusty and erratic outflow winds, locally rough seas and possible waterspouts.
13/1231 PM.
A moderately long period west-northwest swell will bring hazardous surf conditions to portions of Southwest California late this evening through at least Saturday morning. In addition to the west-northwest swell, a storm system will bring gusty southerly winds which will add a southerly wind swell component to the surf. HIGH SURF ADVISORIES remain in effect for the Central Coast and the Ventura county beaches. Please refer to the LAXCFWLOX and LAXSRFLOX for details.
There is a 20-30% chance that HIGH SURF ADVISORIES may be needed for the LA county beaches, beginning Friday morning.
Ca, Flood Watch remains in effect from late Friday night through Saturday evening for zones 87-88-346>348-353>358-362-366>375-377>383-548>550. (See LAXFFALOX). Wind Advisory now in effect until 3 AM PST Friday for zones 340>348. (See LAXNPWLOX). High Surf Advisory in effect until 9 AM PST Saturday for zones 340-346. (See LAXCFWLOX). Flood Watch remains in effect through Saturday evening for zones 349>352-376. (See LAXFFALOX). High Surf Advisory in effect from 3 AM Friday to 9 AM PST Saturday for zone 354. (See LAXCFWLOX). PZ, Small Craft Advisory in effect until 3 PM PST Friday for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until 11 AM PST Friday for zone 655. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PST Saturday for zone 676. (See LAXMWWLOX).
