Aug. 12 chaselog

[dean]

boy, was this a weird bust! drove up to the Wahpeton, ND area to get data. ended up with nothing but heavy rain pretty much all day. Normally you hear people complain about too strong of a cap, well today there was too weak of a cap. everything and anything that wanted to fire did, causing an unbelievable mess of rain showers taking away energy for what was supposed to be for the supercells later in the afternoon. Second thing is any storms that did fire went linear almost instantly (for whatever reason, shear looked to be too good for that to happen, but it did anyway) and became part of a growing area of showers and imbedded thunderstorms. The only real storms that were worth chasing were the tor warned cells in northeast ND early in the afternoon, or the line of storms in central SD, and just my luck i was caught right in the middle between those two areas. Decided to head north towards Grand Forks because those cells were tor warned. New cells started to form, we thought our luck had finally arrived, but they quickly became linear and joined the big swath of thundershowers. Anyways, to sum it up, too little cap lead to too much small convection meaning not enough room for the big boys to come in later. Saw some awesome CC and CG lightning on the way back but that's about it. BUST!!

[wxmann_91]

Second thing is any storms that did fire went linear almost instantly (for whatever reason, shear looked to be too good for that to happen, but it did anyway) and became part of a growing area of showers and imbedded thunderstorms.

That was the main reason for the bust today. SPC mentioned it in the 20Z outlook. Deep layer shear vector backed and became parallel to the frontal boundary; and the best dynamics lagged behind the front.

[WindRunner]

I was watching those storms just from the SPC front page loop, and when I saw a ton of reds starting to pop up around mid-afternoon, I thought something was up, as you never see convection fire that early on a good day. Didn't get a chance to follow it last evening, but doesn't seem like I missed much.

And Jim (or anyone else), could you explain what happened with a bit more detail? I'm not entirely sure I understand why these things went linear last night.