6/20/2010

 

 

Haha, where to begin.  Normally I wouldn't add an entry like this, but today was such an epic failure as far as chasing goes I can't resist.  I guess it wasn't as bad as it could have been.  Even though we didn't see anything at all, at least it wasn't due to a bad mistake made during a great chase day.  This day just completely crapped out on us.  

 

Models had been hinting at a very respectable outbreak of severe weather including tornadoes over eastern Nebraska and western Iowa for days.  Even the night before the forecast models were generally unanimous in developing supercell thunderstorms in this area.  An east/west warm front was located just north of this area, and surface winds were very nicely backed underneath strong mid-level southwesterly winds.  Some models forecast surface CAPE over 5,000j/kg in this area as well, which is very substantial.  

 

To make a long story short, overnight convection blew up over the target area.  It was maintained through the morning hours, and even into the afternoon by an extremely persistent low-level jet.  The mid-morning operational RUC and High-res Rapid Refresh RUC models had indicated this morning "crapvection" getting out of the way by early afternoon, and allowing that area to destabilize.  Those models also forecast supercell thunderstorm development over eastern Nebraska/western Iowa as well.  On top of that SPC also agreed, and had that area in a 10% risk area for tornadoes.  

 

We felt pretty confident when we left the QC that the elevated storms in that area would crap out and get out of the way in time to allow destabilization.  As we drove down I-80 through Iowa we watched as thunderstorms continually developed over the same areas.  At one point we were VERY close to turning around.  I believe that was just east of Des Moines.  However, a few models continued to bang the drum about the risk of supercell thunderstorm development out near the Missouri River, so we pushed on.  

 

By around 3pm we were near Adair Iowa, which is about half way between Des Moines and the Nebraska border.  Weak storms continued to fire over the area of interest, sapping the instability from the target area.  Right around that time the new SPC outlook came out, and continued the 10% tornado risk.  Even though everything we were looking at begged us to call it a day and turn around, that SPC outlook gave us renewed hope, so we pushed on.  Even though we usually go more by the models than by what SPC forecasts, SPC is obviously very good and can't be "sneezed at".  

 

We eventually found ourselves all the way to just east of Columbus Nebraska by around 5pm.  Right around that time we could see the hand writing on the wall.  Even though the elevated storms were finally beginning to push out of eastern Nebraska, the damage had already been done.  Eastern Nebraska was sort of in a dead zone for surface storm development.  For anything to go tornadic, you need storms to be surface based.  The earlier storms had spit up and chewed out the boundary layer's instability for the day.  The best surface instability, and hence best chance for tornadoes was now way down in Kansas.  We briefly thought about making a run at that, but Jeremy had work obligations, and the storms down in that area weren't all too impressive anyway.  

 

So around 6pm we called it a day and began the LONG trek back home.  Man I gotta tell you that was a depressing feeling knowing we had a 7 hour long drive back home, with absolutely NOTHING to show from it.  We had basically driven all the way out to Nebraska only to turn right around and come back home without ever chasing a single storm!

 

Looking back on it we should have just turned around when we were back in central Iowa when we realized those elevated storms just weren't going to stop firing.  Hindsight is always 20/20 though.  After we had made it that far we couldn't stand the thought of turning back around and going home, only to find out that tornadic storms did in fact develop over the area we would have been in.  It's very hard sometimes knowing when and where to draw the line on a chase like that.  You go back and forth in your mind several times before making the decision what to do.  Sometimes you make the right decision, and sometimes you don't.  Obviously on this day we didn't!

 

Here's a few pics from the day.  

 

This is the water tower in the town of Adair.  It was just after here where we almost turned around for home for the second time.  

 

 

 

This is a shot at an impressive looking thunderhead near the Nebraska/Iowa border.  This looks impressive from a distance, but it was not rooted in the boundary layer.  This thing was highly elevated, and hence had zero chance at going tornadic.