Showers and Storms This Week - Update

The forecast for our upcoming round of thunderstorms has actually changed very little from our previous blog.  But as we draw closer to the event, there are other computer forecasts that can help us visualize what might happen.  These only make forecasts out 2 or 3 days, so they're only useful a day or two before the event.

First, there are a few computer models that actually think that a few storms could pop up this afternoon (Wednesday).  The best chance for storms today is over the mountains.  But here is one model's idea for around 5pm this afternoon.  Nothing to write home about, but don't be surprised if you hear thunder later today.



Thursday will definitely see a lot more activity.  A few models have some weaker storms popping over the mountains during the morning hours, but the afternoon and evening are when storms will be more numerous.  Here's a few different model forecasts for 5pm Thursday.





They're all a little different.  One thing to note is that the storms aren't confined over the mountains.  They will also fire off over the valleys and Basin.  As the storms die off Thursday evening, there will be a good chance of rain for most areas.  Here's a 24-hour average rainfall forecast from these various models valid by early Friday morning.



Thunderstorms will fire off again on Friday.  This time most of the activity will be north of Highway 2.

We talked in the previous blog about the structure of these storms.  With weak wind aloft, these storms won't move very fast.  But they will also be more vertically oriented.  This tends to give them shorter lifespans, as their rain falls down the middle of the storm, effectively killing the storm. 

A few factors to consider.  Our atmospheric moisture will be very high, about 200% of normal.  This means that these storms can dump a good amount of rain in a short time.  Also, they can generate strong wind gusts near the storm that fan out in just about any direction.

Here's a wind gust forecast for Thursday afternoon from these models.  Don't get too hung up about the exact location.  But there are areas in the Basin with wind gusts of 40-60 mph.  These kinds of gusts won't play nice with a fluffy windrow, but they will be rather isolated.


Hail is also possible in the center of these storms.  However, with such a hot atmosphere, a lot of the hail will melt as it falls.

Looking farther into the future, temperatures will be cooler this weekend, falling back into the 80s.  A Pacific disturbance will swing by on Monday for a chance of showers, mainly over southeast Washington.  Temperatures will cool further, to around 80 for the majority of next week with a small chance of showers.  Hot weather could return by next weekend.





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