Wednesday, April 21, 2010

Friday Tornado Potential

I'm becoming increasingly confident in a few tornadoes occurring in far NE Missouri, and possibly western Illinois into the evening hours. Target at 60 hours out would be in a region bounded by Quincy to Columbia to St. Louis. This is very chaseable terrain and road wise.

Vorticity maximum and associated 500 jet max will be screaming into central Missouri by noon. This, coupled with impressive 0-3km cape values and sbcape values around 1000-1500 j/kg should lead to the initiation of robust convection by mid-afternoon. Incredible looped hodographs in the vicinity of the warm front will be more than favorable for rotating storms, possibly minisupercells that should be more than capable of producing tornadoes. The cap should be pretty weak, so my main concern at this point is too much early convection associated with the speed max too early in the day. Obviously another question as always will be the amount of destabilization that occurs, which goes hand in hand with the potential issue of too much early convection.

It would be really hard for me to turn down a hodograph like this however, if it appears destabilization appears likely. Time sensitive link valid until Tuesday night.

At this point however, I think the NE quadrant of Missouri bears close watching, perhaps stretching into western Illinois during the late evening.

The other obvious target is in eastern Nebraska right now. The obvious issue with this area is the flow at H5. The stronger jet max is punching into Missouri during the evening leaving Nebraska under fairly weak and southerly flow. Strongly backed flow at 850 could compensate for this however and be sufficient for a few tornado reports. My main concern in this area is that the show ends up being more of a QLCS event quickly as convection becomes widespread. Severe weather is an almost sure thing in this area, but the flow at H5 is what is potentially keeping is from being a bigger tornado producer. Lincoln, NE would be a good starting point for this target. Maybe a hair north of that.

Here's a quick google map image of my tentative target region at 60 hours out for April 23 2010.

View April 23 2010 Threat Area in a larger map

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