Was it a "derecho" that hit Kansas? And a preview of what comes next

The damaging wind event that hit Kansas is something we will be talking about for a long time. I'm not sure I've ever seen anything like it and that seems to be a sentiment shared with others. There were many things that were impressive about that day, not the least of which was this report from Storm Prediction Center from Norman, OK. 

Hurricanes produce these kinds of winds, but actual reports (ground truth observations) can sometimes be fairly isolated when hurricanes are making landfall. Only the most intense hurricanes produce widespread wind reports like the Plains saw on Wednesday.

We had some discussion after the fact about the setup and why such enhancement to the wind. A strong low pressure moved out of Colorado and into Nebraska, but there were thunderstorms that also developed along an advancing cold front through central and northern Kansas. This may have set off a "derecho" - which is a basically a long-lived, widespread wind event, usually associated with thunderstorms. There are some criteria it has to meet:

• Must be at least 250 miles long (Wednesday storms stretched from Oklahoma to Minnesota)
• Wind reports must be 58mph or greater for most of the line
• Must be other wind reports of 75mph or stronger with the line (we had multiple 80-100 mph reports & not just in Kansas)

These would be more common in summer across the northern Plains and upper Midwest and they can travel hundreds of miles. How they form can get pretty deep, but in the image above, the entire line of storms is moving to the right. New storms form on the front end of the line as the entire thing keeps moving along. On the back side (which is what may have happened in Russell and many other areas of central and northern Kansas), there was a strong jet that develop on the backside (usually associated with cooler air descending from above). When that wind started hitting the ground, things went from bad to worse. We are thinking of everybody that had some kind of loss in Wednesday's windstorm and hope the cleanup and recovery is speedy. 

Is the cold finally coming on?

We've been talking about it and hinting at it for weeks now. Every time we think things are changing around, the warm air comes surging right back. We are seeing a high pressure developing in the Gulf of Alaska and another one near Greenland. This is usually a pretty good signal for the onset of much colder air diving south into the lower 48. There's evidence of this around Christmas and into New Years, so let's continue to watch. If this cuts loose, we could be in for a stretch of true winter weather - maybe not record cold, but more along the lines of what we would typically get this time of year anyway.  

I still don't see anything on the horizon yet for moisture - at least nothing that looks promising yet. 

This will be the last blog post prior to Christmas - happy holidays. Hope you'll check back in right after Christmas.