Tuesday, November 29, 2016

Model Mayhem

That title might be a bit of an exaggeration, but there continues to be significant differences for the weekend, but that might not translate into significant differences in the forecast.  I'll explain in just a second.

If you watched the blog video I posted Monday, you know there were two runs of the European which showed weekend rain with a possible changeover to something "other than rain" by the time it came to an end Sunday over far northern Arkansas.  The overnight run today (Tuesday) shows the same scenario but does NOT have air cold enough to change it over Sunday.  It does however for southern Missouri.

As you know from watching the blog video yesterday, this blog is not intended to give you a forecast, but to show you what goes into making a forecast.  With that said, even one model run 5 days out does NOT end my speculation as to what could happen.  It only reinforces my belief that models waffle ALL... THE... TIME.

Now onto what the models indicate this morning.  The GFS continues to hold the low out to the southwest until Monday.  Ahead of it, a moist southwest flow aloft may bring rain chances with embedded disturbances this weekend.

The Euro brings the whole thing through later Sunday and therefore faster than the GFS.  The newest version of the Euro is not as wound up and does not bring air cold enough to support something "other than rain".

So while the mechanisms to produce rainfall are different and have different timing on each of the models, the end result is the same, a wet and chilly weekend.

Will there be something "other than rain" over northern Arkansas?  It's too early to tell.

The Euro valid Sunday at 6PM has the upper low out of the southwestern United States and in east Texas.  This is the faster timing I was talking about.

The GFS at 6PM Monday has the low still over western Mexico, but it rapidly ejects it out on Monday.  This is the slower solution.  However, even with this scenario, there will be some rain chances as a moist southwest flow brings embedded disturbances ahead of the main low.

Courtesy of EuroWX.com.   The overnight run of the Euro does NOT wrap air cold enough to support something "other than rain" in Arkansas, but you see some amounts of something "other than rain" in southern Missouri.  It's not impossible for a changeover across far northern Arkansas.  However, at this time and based upon the newest data, the chances are not all that good.

No comments:

NOAA Winter Guidance