14/758 PM.
An unusually strong storm system will bring widespread rain to the area through Sunday. The heaviest rain will fall late tonight through early Saturday afternoon. During the peak of the event isolated strong thunderstorms will bring a moderate risk of flash flooding, debris flows, and damaging winds. The stormy pattern will continue and periods of rain are possible through late next week.
(tdy-Sun), 14/849 PM.
, MODERATE TO HIGH RISK OF DANGEROUS FLASH FLOODING, DEBRIS FLOWS, AND DAMAGING WINDS TONIGHT THROUGH SATURDAY NIGHT,
***UPDATE***
The storm has shifted into the 2nd phase as this morning's cold front has exited the area. Phase 2 involves an upper low that is currently 300 miles to the SW of KLAX. A low level jet riding up the east side of the has added plenty of energy and has even produced a baroclinic leaf. PWs in this plume of mositure are near 1.4 inches (about 1 inch anomaly). This will bring steady lgt-mdt rain to most of LA/VTA county this evening and into the overnight hours.
All eyes on the period from approximately 400am to noon Saturday with a strong compact vort lobe moves into the area. This vort lobe will kick the storm up an notch and the rain will become moderate with pockets of heavy rain. There will be enough lift and instability to bring a chc of TSTMs. While there is enough twist in the lower atmosphere to allow any TSTM that forms to produce severe weather or even a weak tornado, the real threat will be the rainfall rates which will be close to 1 inch per hour. These rainfall rates on top of the already saturated grounds will could well produce flash flooding anywhere. The recent burn areas, of course, will be most vulnerable to flash flooding and debris flows. A flash flood watch is in effect for all of the area.
This is a dangerous situation and all residents of LA/VTA and eastern SBA counties are urged to monitor this storm closely and follow the directions of all emergency personnel.
***From Previous Discussion***
There will be a very noticeable break in the steady widespread nature of the rain Saturday Night, but scattered off and on again light to moderate showers will remain over the area through Sunday. The highest chances are over eastern Los Angeles County and northern SLO County Saturday Night, then really anywhere on Sunday. Any additional impacts will be minor.
The break will be brief as the next storm will start to impact the area Sunday Night, first over San Luis Obispo County then pushing south into Los Angeles County on Monday. After a cold front brings light to moderate rain with minor impacts, there is a good chance for the core of the system to move through the area Monday Night and Tuesday keeping showers going and possibly bringing some snow levels down to 5,000 feet. The BIG different between this storm and our current storm is that the Tuesday system will not cut off but will remain plugged into the jet. This means it will move through fairly quickly which means rain amounts and impacts will be on the lower end.
(Mon-Thu), 14/206 PM.
There should be a break in the rain on Wednesday, but yet another storm will be in the window Wednesday through Friday. This one carries much more uncertainity that Monday's storm, as really anything is on the table between no rain and a lot of rain. Cooler than normal conditions will remain.
14/2351z.
At 23Z at KLAX, there was no marine layer.
Overall, low confidence in 00Z TAF package. High confidence in periods of rain for all sites through the period, but low confidence in timing of flight category changes (and the flight categories themselves). CIGs and VSBYs will vary from VFR levels down to IFR through the period.
There is a 20% chance of thunderstorms for TAF sites south of Point Conception thru the fcst period. Any thunderstorms will be capable of producing heavy rain, frequent lightning and gusty/erratic outflow winds.
KLAX, Low confidence in 00Z TAF. High confidence in varying intensities of rainfall through the period. However, low confidence in timing of flight category changes as well as the flight categories themselves. MVFR conditions most likely through this evening with IFR conditions becoming more likely overnight. Through 11Z, there is a 50-60% chance of easterly winds above 8 knots, then a 60-80% chance of easterly winds above 10 knots 11Z-17Z.
KBUR, Low confidence in 00Z TAF. High confidence in varying intensities of rainfall through the period. However, low confidence in timing of flight category changes as well as the flight categories themselves. MVFR conditions most likely through this evening with IFR conditions becoming more likely overnight.
14/735 PM.
There is a 20-30% chance of thunderstorms across the coastal waters south of Point Conception through Saturday night. Any thunderstorms that develop will be capable of producing brief heavy rain, dangerous cloud to surface lightning, gusty and erratic winds, locally rough seas and possible waterspouts.
For the Outer Waters, moderate to high confidence in current forecast. Tonight through Saturday afternoon, high confidence in Small Craft Advisory (SCA) level seas and a 30% chance of SCA level winds, mainly in the southernmost outer waters. From Saturday afternoon through Sunday, moderate to high confidence in winds and seas remaining below SCA levels. For Monday and Tuesday, high confidence in SCA level seas with a 30-40% chance of SCA level winds. For Wednesday, high confidence in winds and seas remaining below SCA levels.
For the Inner Waters north of Point Sal, moderate to high confidence in SCA level seas through Saturday afternoon. For Saturday afternoon through Sunday, high confidence in winds and seas remaining below SCA levels. For Monday through Tuesday, high confidence in SCA level seas with a 30-40% chance of SCA level winds on Monday. For Tuesday through Wednesday, high confidence in winds and seas remaining below SCA levels.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Moderate confidence in SCA level southeast winds tonight and Saturday morning across PZZ655, and SCA level seas across the western Santa Barbara Channel. For Saturday afternoon through Sunday, high confidence in winds and seas remaining below SCA levels. On Monday, there is a 60-80% chance of SCA level winds across all the southern Inner Waters. For Tuesday through Wednesday, high confidence in winds and seas remaining below SCA levels.
14/1248 PM.
A moderately long period west-northwest swell will bring hazardous surf conditions to portions of Southwest California today 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 today and tonight.
Additionally, there is a 20-30% chance of thunderstorms across all the beaches at times from late this afternoon through Saturday night. Any thunderstorms that form will be capable of producing locally strong winds, small hail, dangerous lightning, heavy rainfall, and possibly even a weak/brief tornado.
Ca, Flood Watch now in effect from 1 AM PST Saturday through Saturday evening for zones 87-88-346>358-362-366>383-548>550. (See LAXFFALOX). High Surf Advisory in effect until 3 PM PST Saturday for zones 340-346-354-362-366. (See LAXCFWLOX). Beach Hazards Statement in effect through Saturday afternoon for zones 349-350. (See LAXCFWLOX). PZ, Small Craft Advisory in effect until 3 PM PST Saturday for zones 645-670-673-676. (See LAXMWWLOX). Small Craft Advisory in effect until 11 AM PST Saturday for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect from 3 AM to 3 PM PST Saturday for zone 655. (See LAXMWWLOX).
