Cut-off low pressure forms
If you look closely at the satellite image above, you’ll see what appears to be a coma shape line of clouds that stretches all the way down into southern Nevada. This is the tail of low that is spinning between Idaho, Utah and Nevada. The computer models are now indicating that this low is going to stall over the Great Basin. This means the low is “cut-off” from the main steering currents in the atmosphere. Eventually, the low will weaken to the point that it becomes insignificant.
For now, the occasional showers will move through parts of the valley on Saturday. Temperatures will remain cool with highs in the 60’s. The farther north you go, the fewer showers you’ll see. For example, up towards the Long Valley, there is only a slight chance of a shower in the forecast because this area is more detached from the center of the low.
By Mother’s Day, the low should begin to weaken and produce less of a chance of rain. But, there could still be a few spotty showers in the Treasure Valley on Sunday mixed in with some sunshine as well. Temperatures Sunday will manage to warm to the upper 60’s.
The unsettled nature of the weather we have seen and will see this weekend is all par for the course. Typically, we should be seeing more significant storms in May, but, it has been drier than normal this spring.