No One Knows What the Weekend Weather Will Be

I've talked in the past in this blog that there are literally over 100 computer forecasts that predict the weather for the next 10 days.  And the science of using these is to generate statistics from them, rather than try to pick which one will be the most accurate.  Usually, the forecasts are all fairly close to each other.  But in some instances, like this coming weekend, the computers have some big differences of opinion.

Below is the high/low temperature forecast for Deer Park for the next 10 days.  The red boxes are the forecast high temperature.  The height of the box shows how much the computers agree or disagree.  For the next 4 days, the boxes are all very short.  This means that the computers all agree on the high temperature to within a few degrees of each other.  We'll have highs in the 50s to around 60F through Thursday.  But then on Friday and especially Saturday, the boxes get really tall.  In other words, there's a big disagreement on temperatures for those days.  On Saturday, some computers are calling for a high of only 53F, while others are going for a record hot day of 82F.  That's quite a spread.  Why is this?


At the end of my last blog, I pointed out that a weather system will arrive around Friday, and that the U.S. models were coming into agreement with the European models on this.  Well they're still searching for the best forecast and can't make up their minds.  There's a lot of uncertainty.

The image below is a little hard to understand.  I've shown it in the past, but I'll briefly describe it again.  If you took all 100 computer forecasts and average them all together, you'd get the weather map in the bottom center.  This shows a cold low dropping into California with warmer high pressure over the central US.


But there are fancy mathematical ways that look at those 100 forecasts and group similar predictions into 4 different categories.  That's what the other 4 images are.  Cluster 1 (upper left) shows a very cold low over northern California.  But more importantly, it shows the warmer high pressure from the central US bending back into our area.  Cluster 2 (top center) has the deep low over California, but also cold over the Northwest.  Cluster 3 (upper right) is faster, with the weather system already moving to our east.  Cluster 4 (lower left) is similar to Cluster 1 (upper left), but the warm high pressure is even stronger over the Northwest.

Any of these scenarios is possible at this point.  If Cluster 4 is correct, we'll have record hot weather with temperatures in the 80s for Saturday.  But if Cluster 2 is right, it will be showery with temperatures in the 50s.  We'll have to wait a few more days before the computers come up with an agreed-upon forecast.  Now only 10% of the computers are going with the record hot scenario.  But the trend of the computers has been to forecast the low farther south.  We'll see if that trend continues.

Until then, look for a weak weather system to bring some showers to our area Monday night and Tuesday.  Then after a dry Wednesday and Thursday, we get into the uncertain weekend.  Could be hot and dry; could be cool and showery.  No one knows at this point.



If you have any comments on this blog, or need a forecast for a specific activity, don't hesitate to email me at inlandnorthwesthayweather@gmail.com  I won't share your information with anyone and I won't try to sell you anything.




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