Before everyone gets too excited, this question is about one computer model more than a week ahead and is based on the movement of an initially tropical system. In other words, don't get your hopes up yet. This is, just right now, a fun look at one long-range computer model.
With the arrival of the 12Z GFS today, one thing that stuck out like a sore thumb was an area of rain it was bringing up into Southern California on Sept. 29 and 30. Here is the surface map for Sept. 29.
Where does this come from? Well, there is currently an area of disturbed weather located several hundred miles south of Acapulco, Mexico.
Current computer models, including tropical models, continue to develop this area over the next few days into a tropical storm then hurricane and tracks it generally to the northwest into early next week. Then the hurricane models start to diverge, from turning the developing storm to the north or turning it to the west. Obviously, the GFS is taking that low more north and capturing at least the moisture from it late in the week from a closed low sitting west of Southern California. This is also the GFS from Sept. 29.
Pure fiction or a rain maker? No answers right now. I am not even going to hazard a guess. Don't get me wrong, I am not even considering this being a tropical low into Southern California. But will the moisture come north and bring rain? Odds are against it and at best it is a long shot. This occasionally happens but many more times than not it doesn't. Just so you know, the European has absolutely no hint of this as it keeps the moisture way, way south and west. However, it is kind of fun to conjecture at this point and consider it just that for now.
With such high amounts of water vapor, thunderstorms will bring locally very heavy rain that can cause flash flooding.
Many areas east of the Cascades this weekend will be over 100 F.
some of the moisture from Andres and newly formed Blanca could influence the weather in the Southwest
A powerful second punch is offshore right now and comes inland during the early morning hours. It will bring moderate to heavy rain for the Friday morning rush.
The main storm will move in off the Pacific Thursday and Friday.
Last year by the end of April the drought in California was very bad. Since then it has become even worse.