SoCal Weather Watcher

Composite Radar 11/15/25 12PM - A cutoff Low Pressure system continues its slow advance across #SoCal. Most of the rainfall has been light/moderate for most locations. Heavier bands of rain will be coming ashore into LA/OC Metro areas over the next few hours.

- Some areas will see heavy Thunderstorms and excessive rainfall rates that will cause runoff issues, local street flooding, etc.

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Latest HRRR Simulated Radar depiction through 4PM Sunday - Heaviest rainfall will move through the region between late Tonight and Saturday afternoon.
#CAwx #LArain

2/3)

- Given the abundant moisture available, expected dynamics, and the overall nature of cutoff lows, the potential is there for totals similar to the higher amounts shown by the other Model solutions.

1/3) A quick peek of some of this evening's latest High-Resolution Guidance for Rainfall amounts between now and Sunday PM for #SoCal:

- While not as crazy as what some of the Deterministic models have been putting out lately, these amounts will still be adding to whatever has already fallen.

* WHAT...Flooding caused by excessive rainfall is expected. * WHERE...A portion of western Los Angeles County. * WHEN...Until 1230 AM PST Saturday. * IMPACTS...Minor flooding in low-lying and poor drainage areas. Water over roadways. * ADDITIONAL DETAILS... - At 628 PM PST, Doppler radar and automated rain gauges indicated heavy rain. Minor flooding is already occurring in the advisory area. Between 0.2 and 0.7 inches of rain have fallen. - Additional rainfall amounts of 0.2 to 1 inch are expected over the area. This additional rain will result in minor flooding. - Some locations that will experience flooding include... Acton, Santa Clarita, Northridge, Van Nuys, North Hollywood, Burbank, Chatsworth, Universal City, Encino, Griffith Park, Palmdale, Hollywood, Lancaster, Woodland Hills, Beverly Hills, Pasadena, Downtown Los Angeles, Santa Monica, Culver City, the Hughes burn scar and other recent small burn scars. - http://www.weather.gov/safety/flood

Flood Advisory issued November 14 at 6:30PM PST until November 15 at 12:30AM PST by NWS Los Angeles/Oxnard CA
Additional Details Here.

Model Guidance is currently suggesting the West Coast, including #SoCal will remain in a stormy pattern through next week and into the following weekend with multiple systems moving through the region. (12z Euro deterministic run shown) #CAwx #LArain

HRRR Model's Simulated Radar through 2pm Saturday - Rainfall will decrease this afternoon before the next surge of showers moves into #SoCal late tonight through tomorrow PM. Periods of heavy Rainfall and possible Thunderstorms will be likely throughout the day on Saturday. #CAwx #LArain #SoCalStorm

Map from NAEFS Situational Awareness Tool (NOAA) depicting record column integrated vapor transport over Southern California.

Map from NAEFS Situational Awareness Tool (NOAA) depicting near-record column water vapor over Southern California.

One of the reasons why this weekend's storm system is looking so impressive is that the associated airmass will be among the moistest on record for November in SoCal, with record or near-record column water vapor and integrated vapor transport in some areas. #CAwx

Snapshot of current ECMWF model ensemble prediction of precipitation over the next 2 weeks for a point near Los Angeles. 2-4 inches of rain are highly likely this weekend, which represents a major November storm! But only 1 in 51 (<2%) of ensemble members show ~10 inches of rain this week--making it an extreme, and very unlikely, outlier.

California weather PSA:

Fact: Major SoCal storm *is* likely this weekend, w/2-4 inches of rain & t-storms possible in LA (more in mtns) & notable flood/debris flow risk in some spots.

Context: Snapshots showing ~10 inches of rain are extreme outliers, & very unlikely!

The Hi Res NAM's Simulated Radar depiction through Saturday PM provides a good illustration of the multiple waves of moisture that will be fed into #SoCal, starting with the Cold Front Tonight/Friday AM, and then the Southerly surge of moisture on Saturday as the Cutoff Low approaches. #CAwx #LArain

GOES West Satellite - A Low Pressure system centered about 200 miles West of Crescent City will drop South and cut off near #SoCal this weekend, spinning waves of moderate to heavy Rainfall into the region through this weekend. Rainfall will reach SLO/SB & Ventura tonight, and LA/OC by morning.

From NWS Los Angeles:
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Good afternoon, this is our lasted rain forecast. We have good confidence in Thur/Thur night w a front passage, but low confidence Fri-Sun. This is because a closed low brings rain chcs Fri-Sun & models struggle greatly with this pattern. Stay tuned, as things may change.

3/3) More than likely, Coastal areas will see something closer to what the Model Blend below suggests - 1.5" to 3.5" through Sunday PM, with Foothills seeing higher amounts. The rub being that this all depends on a cut-off system behaving as expected, which they notoriously don't like to do. #CAwx

2/3) Cut-off Lows have a tendency to behave in unexpected ways. The precise track of the Low, and how long it lingers around #SoCal will determine rainfall amounts. Some Model runs have spit out some impressive totals for Fri-Sun, with the GFS painting big totals for Ventura and SB Counties...

1/3) Model Guidance tools continue to disagree on details, but they do agree that #SoCal will see periods of moderate to heavy rainfall between late Thursday night and Sunday as the system slows down, cuts off and stalls near the area before moving East, with another storm on its heels for Monday...

2/2) The System will Move through #SoCal on Thursday before moving East into Arizona with a few lingering showers across portions of SoCal on Friday, before clearing out on Saturday. #CAwx #AZwx

1/2) A peek at what the latest Guidance is suggesting for #SoCal rainfall totals Thurs-Friday. Generally 1"-2" for Coastal and Valley areas with greater amounts in the higher elevations. Snow levels will remain above 6,000ft, so not a big snow producer for Mtn Resorts.

After the big warmup through early next week for #SoCal, Model/Ensemble guidance continues to point to a colder, unsettled pattern developing late next week.

Will have a better idea of expected Rain totals and impacts by Monday as Deterministic Models converge on the details. #CAwx #AZwx

#SoCal warms up this weekend into early next week as Santa Ana conditions set up & daytime temps flirt with the lower 90's by Monday. The heat will begin to moderate on Tuesday. A pattern change to cool unsettled weather with rain chances for late next week/next weekend is still on track. #CAwx

Next week will likely see some big swings in the Weather across #SoCal. A Ridge will strengthen and warm temperatures into the 90's for some locations Sunday/Monday, followed by a Trough and cooler weather, with Ensembles continuing to signal a good chance for Rain/Mtn Snow late in the week. #CAwx

The pattern change signaled in long-range Ensemble Guidance for mid-November is now being reflected in @NWSCPC 6-10 & 8-14 Day outlooks, with a transition to unsettled weather for #SoCal possible later next week. #CAwx #AZwx

www.cpc.ncep.noaa.gov

Both Euro and GEFS Long Range Ensemble guidance is signaling a shift to a more favorable pattern for #SoCal Rainfall/Mtn Snowfall around mid-November. Will be watching this closely. #CAwx

A Pacific Storm will move through Northern and Central California next Tuesday-Wednesday. Some light showers may reach as far South and Santa Barbara County, but most of #SoCal will remain dry through at least the next 10-12 days. #CAwx

Still no signs of rain/snow for #SoCal through the next several days.

Looking farther ahead - Long Range Ensembles are hinting at the possibility of a West Coast trough pattern setting up after mid-November, but it's WAY too early to trust any details just yet. #CAwx

Our October heat will begin to subside after today, with temperatures getting back to seasonal norms by this weekend. Long range Guidance continues to suggest that the storm track will remain to the North of #SoCal through early November. (Euro EPS Ensemble shown).

October Heat is arriving in #SoCal, ushered in by offshore flow/Santa Ana conditions. Tuesday & Wednesday will be the warmest days, with daytime temperatures in many locations up into the 90's. Thursday and Friday will be warm, but not quite as hot. #CAwx

Ensemble Guidance is advertising an extended period of ridging & warm/dry weather for the West Coast. A trough will bring rain to the Pacific NW and NorCal along with some cooling for #SoCal this weekend, followed by a West Coast Ridge building in early next week and lasting for several days. #CAwx

Looking ahead - The pattern for the next several days across #SoCal will be dominated by frequent Ridging in the Western US, with any rainfall remaining North of the region and generally warm/dry weather through the next 10 - 12 days. #CAwx

Composite Radar as of 7:24PM 10/21/25 - A Cutoff Low Pressure System is producing some instability aloft across portions of #SoCal. There is the possibility for sprinkles or a brief light shower tonight, and a chance for some Marine Layer Drizzle in Coastal & Metro Areas Wednesday Morning. #CAwx

NAM Model Simulated IR Satellite through 48hrs - A Cutoff Low will bring cooling temperatures, Marine Layer Drizzle and possibly even a shower or two to #SoCal locations tomorrow night/Wednesday AM. The system will move East by Thursday and temperatures will rebound. #CAwx