Strong Hurricane Miriam is swirling south-southwest of the southern tip of the Baja and moving northwest. Miriam's signature on satellite pictures this afternoon is not quite as impressive as earlier in the day as the eye just is not quite as sharp. Still it is a formidable storm but out to sea, for now.
Miriam has about another 12 to 18 hours for any further intensification, but after that, it will start to move over cooler sea surface temperatures and weakening will begin. These Eastern Pacific storms tend to increase quicker than models can handle but also can weaken faster, too. Since Miriam is so strong now, it will take some time for winds to come down. After continuing northwest into tomorrow, a more northerly course is expected midweek then a turn to the northeast. Most of the hurricane models are in agreement with this and so to is the European, though the European is about 18 to 24 hours quicker moving it into the central Baja on Friday.
These models would take the moisture from Miriam and send it into western Texas and New Mexico and perhaps parts of southeastern Arizona.
However, the operational GFS uses a closed upper-level low west of Southern California in the late week to help turn what is left of Miriam more north and brings increasing moisture toward Southern California.
While this scenario seems to be the far less likely one, the chance today is not zero either. Remember as of last Thursday, the GFS was forecasting moisture to come north into Southern California. For now, I am putting many of my eggs in the farther east solution, but I am withholding an egg or two. One never knows when you might just need that egg when it comes to weather forecasting.
These is the possibility that another surge of tropical moisture could move into Arizona and Southern California by the middle of next week.
I still believe the greatest amount of rain, at least partially relating to Norbert, occurs from southeast California to Arizona
The effects on Southern California are very much in question.
With low wind shear and warm water in its path for a while longer, it is likely that Norbert intensifies into at least a Category 2 storm.
For much of the last week the monsoon moisture flow into the Southwest has been completely shut down by dry westerly winds. This is about to change.
A big pattern change is underway, one that will completely shut down any chance of showers and thunderstorms for an extended time period.