Showers Possible Monday Night or Tuesday

In my last blog I said there was no rain in sight aside from some mountain showers near the BC and ID/MT border. I also mentioned that there would be a weak weather system on Monday or Tuesday that would bring us a bit of cooling after a hot weekend. 

The computers are now thinking that the weak weather system could be a bit stronger than previously thought.  If true, this would mean more wind and a better chance of showers. But please understand, there is a LOT of uncertainty and disagreement on this forecast. 

To show you what I mean, below is the temperature forecast for Deer Park. I’ve shown this graph before, but it’s been awhile. Basically, instead of predicting a single high or low temperature, it shows the range of possibilities. The bigger the box, the larger the range of possible temperatures. 


See that big red box on Tuesday?  The range of the computer forecast high temperatures for Tuesday is from 70F to 101F. You won’t see that on any app or TV forecast.  That’s a lot of uncertainty. So some computer forecasts have a cool (and probably wet) Tuesday, while others scoff at that idea and predict triple digits.

Let me show you an example.  First, here’s the US model the GFS, 24 hour precipitation forecast ending Tuesday evening. 


The GFS thinks all the rains will stay up to our north.  Nothing to worry about. 

Now look at the UK computer forecast.


It predicts that rain will spread all the way down to Ritzville. Quit a difference. 

And here’s the European computer forecast. 



Somewhere in the middle. 

Here’s a summary of the rain chances for the next 10 days. Low, but not zero.  You can also see that a few computers see a chance of rain Wednesday night and Thursday, but the probability of this is even lower. 




I also mentioned a windier forecast.   Here’s the prediction for Spokane Airport. 


The wind will increase from the southwest on Monday. Then it will switch Monday night, coming from the northeast. Notice how it will stay rather strong all night long. Forget about any chances of dew on Monday night or Tuesday night with this forecast. Nighttime temperatures will also be uncomfortably warm. 




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