Recent model runs continue to indicate significant rainfall potential later this week.
After an extreme and prolonged dry period, it appears Los Angeles will be in for two very significant storms beginning this Thursday.
The very latest precipitation model run continues to trend two storms, the first of which should now be more significant than previous models had suggested.
Two distinct waves of energy continue to approach California. These surface and upper air disturbances have been moving across the Pacific for the last several days, and until yesterday, models had suggested upwards of 5 inches cumulative rainfall from both. This first of these two storms is moderate in strength, and should bring measurable rain to most of California, including Los Angeles.
The second disturbance still appears to be much stronger, with greater energy further south, concentrated almost directly over Los Angeles beginning late in the day next Friday. If the storm materializes, heavy rainfall could begin moving onshore across the greater L.A. metro area around sunset and continue for a 3 to 6 hour period resulting in as much as one to three inches of rain overnight before spreading south and east to affect much of the balance of southern California.
Rainfall of this intensity could result in flash flood/urban small stream flood conditions across areas of the Southland, and travel may stand to be adversely affected.
Orographic lifting in foothill and mountain areas usually serves to enhance rainfall in this type of scenario, due to a southwest to northeast trajectory of moisture from off the Pacific.
Snow may heavy in mountain areas, accumulating as much as a foot, most likely at elevations of about 6,000 ft. and above.
Currently, it appears Thursday's expected storm may be more significant than previous models had suggested, while Friday's storm will be only very slightly intense than previous model runs had depicted.
Cumulative rainfall from both storms still could total from 2 to 4 inches in coastal and mountain areas of southern California.