The lack of the Monsoon this year was predicted by many including myself quite some time ago. The fact is that we have yet to see copious amounts of moisture come up and fall as rain. The rain we have had has been either high elevation convection or some type of upper-level feature (mainly short wave troughs) that come through or near the area that mix with the other ingredients heat and recycled moisture to produce a decent yet spotty downpour.
For today a similar set up will occur, a slight push of moisture into the area, a shortwave trough approaching from the southwest and a hint of the jet stream approaching the area, this is the setup, it looks good on paper, but the models are not that impressed keeping the precipitation mainly up north above 8,500′, but you never know, NWS has 40% chances for a good portion of the lower and mid-elevation areas which seems like a decent hedge.
Fast forward to Saturday late afternoon-evening-night-overnight-Sunday morning and you have a much different story. A larger push of moisture, a large trough from the west, a larger shortwave (than today) tracking in from the southwest and the right front entrance region of the jet all get involved for what appears now to be rain for all. Timing is different between the models but it looks like the best bet is between late afternoon and midnight to start and lasting into Sunday. If the models continue to show this over the next 24 hours we may see some “Heavy Rain” wording come into the forecast which would lead to some flash flood discussions. All said and done, the models are predicting .4″-.7″ for lower and mid-elevations to well over an inch above 8,500′.
I should be able to do a quick update tomorrow morning with the latest from the models. Overnight rain Saturday into Sunday would be great for sleep, I hope this pans out!