Chase Case #5

[David Wolfson]

The SPC has it as April 20th. http://www.spc.noaa.gov/exper/archive/even...0420/index.html

 

[Jeff Snyder]

I think part of the reason why this day's forecast was so bad was that the models did not pick up the situation at all. On the other hand, the 12z and 18z data doesn't look TOO bad. Moisture pooling along the warm front led to mid-60 Tds in central IL and western IN, and there was some insolation occuring as there were breaks in the clouds. And again, that 68/65 with SE sfc winds ob in extreme west-central IN is a doozy. Yes, the lapse rates were poor, but they actually steepened a bit more than I would have thought (I suppose from large-scale upward motion ahead of the wave). Mid-level flow wasn't too bad, and the low-level shear profiles along and immediately ahead of the warm front support strong low-level SRH. On the other hand, hindsight is 20/20, and it's a lot easier to pick up the 'missed data' when you know exactly what to look for and where to look for it (not something easily done when forecasting, which requires anticipating something that hasn't happened yet).

 

[Mark Farnik]

It was April 20th? Ok, my bad. Well, being one day off isn't that bad for an event that happened almost two years ago. Strangely enough I remember all the details, but I slipped up on the date. Oh well. :lol:

 

[Joel Wright]

I remember this day very well (now that the cat's been let out of the bag lol), and I remember not expecting much activity in northern IL that day. The morning was cold, and with stiff east winds and stratiform rain approaching, I figured the warm front would have a tough time advancing into the cold heavy air. So not only was I surprised the warm front actually made it this far north, but it ended up being the main focus for supercells to boot.

After this day I never looked at a warm front the same.

 

[David Draun]

I knew it when I made my post last night. I said that surface data in Chicago was familiar. Then the 18Z radar picture just completely gave it away. As soon as that rain shield went northward, the Utica storm got going in Western IL. That evening I came in from work, and the supercells are just chugging into Will and southern Cook counties. 4/20/04. Chicago didn't even have thunderstorms forecasted that day. :shock:

 

[Dan Cook]

Yup you guys got it. Do you want another one, a non plains/midwest one?

 

[Shane Adams]

Shouldn't the next forecast go to the person who nailed ths one or got the closest?

 

[Kurt Hulst]

I was confused when I saw the 21st, and went and looked at the event archive and saw nothing. But I remeber this day very well. I caught five tornadoes north of Kokomo and SW of Wabash, IN.

 

[Scott Olson]

Neat game, thanks Dan. I had a feeling that something was going to come of boundary interactions in IA. I wish I'd pick Des Moines because it shows a better surface flow and dewpoint.

 

[Chris C Sanner]

For the record, I had no idea of the actual event when I made the post:

"I'm going to cross the mighty Mississippi at St. Louis and park somewhere around 40 miles northeast of there and follow the front all day in Illinois. I can't ignore the highly backed winds in Illinois, especially with decent moisture not too far south of my spot at the present time."

It was merely an instinct seeing how the weather systems layed out and the highly backed winds, so -10 points for me for nailing a forecast in a case but never being able to do it the day of..