Pacific Storm Andreas is a Category Two system at the heart and it is traveling down Northern California and Nevada this evening and will start to impact our region on Sunday. We had Andreas?  No, it never hit and therefore the name was put into the list again for use.  As with hurricanes, you need to read the entire forecast to find out what section of the storm you are in, in terms of category so read it.

Category Two conditions are reserved for the Western half of the High Desert, including the Edwards Air Force Base and Ridgecrest forecast zones southward into some of the Inland Empire areas.  Category two conditions are for higher rainfall totals and a chance thunderstorm activity.  Category One conditions is for a meager event with some showers … or some wind … but can pop an isolated thunderstorm within it and the wording would say if you are or are not in it.

Over the day on Sunday we’ll be in the member section updating.  Check out our member section here for upgrades and goodies, including projections of the 2C model and more … with rapid updates during events.  We are implementing lightning data/radar in this section during tstorm events by October 15th. – Click Here

Pacific Storm Andreas is a normal storm system for this time of year.  The dynamics are a bit further west than previously thought and this is the reason for naming the system.  If you are a premium member you were following along in the ‘rain alert’ section displaying Model 1E and 2C as the best ones offered in terms of accuracy, with 2C in the lead.  So what will happen in more detail?

The upper divergence will approach San Luis Obispo and Vandenberg early on Sunday morning.  At the same time developing upslope showers will be possible in all areas south/west of the mountain areas.  This upper divergence will finally setup stronger from the Inland Empire along a north to south line of convection that would ultimately form into the Western half of the High Desert and Kern County Mountain zones later during the day.

SCWF Thunderstorm models shows cloud tops over the needed 21,000 foot zones in the areas shaded in yellow for ‘most coverage’ in the video provided in this article so make sure you watch it.  Thunderstorms will contain the risk of hail.  In addition to that section of thunderstorm dynamics … we’re watching for the area across Santa Barbara, Ventura, and Los Angeles County through Malibu later on Sunday evening for the center of the cold core and thus it is a very very small but potent zone of upper divergence.  Should this be correct, we may have some convection to deal with offshore through Santa Barbara, Ventura, Point Mugu, Malibu, and the LAX / Santa Monica zones … which could produce isolated thunderstorm risks along with the chance of waterspouts …

Thunderstorms are not expected south of the Inland Empire and Orange County zones … so if you’re in the San Diego areas you’ll be subject only to showers developing on Sunday.  The colder core and upper divergence seems to be placing you in a non-thunderstorm area.

The most rain will be in the Upper High Desert zones North of Barstow … and the Inland Empire forecast areas, especially along the Elsinore Convergence zone.

The least rain at the moment will be for the Morongo Basin and most low desert areas … and into the Bakersfield zones.

Snow levels will remain 8,000 ft. for most of the mountains, but around 7,000 ft. possible in the Kern/Ventura Mountains … only seeing some of the very high locations seeing the flakes.  We won’t be issuing alerts in the community zones for snow … but if you are heading to Mammoth … they’ll be getting 10+ inches of snow from this system if my projections are correct.

Wind gusts will be in the 25-35 mph zones for the mountain/desert areas.  Overnight tonight with the southerly flow, expecting some advisory level breach for the top of the Cajon Pass and even into the Southern High Desert Metro zones.

Las Vegas?  You’ll enter the thunderstorm zone on Sunday and widespread thunderstorms are expected in Las Vegas through the rest of Sunday and Sunday night / Monday … travel carefully.  Some of these could be severe.

What Is Coming Afterwards?  Yeah … we look to get offshore flow and a heat burst toward the end week and into this next week … so enjoy the storm/colder air while it lasts … we could have some of the hottest temperatures in the metro areas this season due to sinking air and offshore winds … fire dangers would be elevated in areas that don’t get enough rain with this storm … regardless stay tuned to Southern California Weather Force.com for the latest on the coming heat/offshore wind/fire hazard …