4/02/06 FCST: IL/IA/MO

[Alex Lamers]

I am a little concerned about how the GFS has taken a jog south with the low, but it would seem to be the result of some convective feedback issues. I expect we'll see some supercells in a small window of 3-7 PM tomorrow across SE/EC IA...NE/NC MO and into far NW IL. After that we should see transition to more quasi-linear modes. Parameters as far as tornado potential goes have been steadily falling off in the past few NAM runs when analyzed near possible convection. Therefore, I am becoming less certain about the tornado threat especially if sfc wind field veers more to the south or south-southwest in the afternoon and better mixing occurs which would decrease SRH and increase LCLs...possibly leading to more unidirectional shear supportive of bow echoes.

 

[SteveCarter]

Looks like this may turn out to be a good day..chasing wise. Degree of low-level shear along with
moist-moderatley unstable airmass suggests that several tornadoes will likely occur...a few of which could be strong and long-lived. The area I'm sticking to is still Mt. Vernon - Vandalia, IL. Is the lack of many posts for this thread due to lack of excitement, or just everyone is out and about? btw - it looks like the storms that are moving this direction now, will be out of this area by early afternoon, which should clean out the debri.

 

[Jason McIntosh]

Well after careful analysis, I have picked SE IA/WC IL as my hot spot for today. Me and my chase partner are going to leave Madison,WI at 8 am and head for the Burlington, IA area. Last time we were close to this location for 3/12/06. All the action stayed to our west that day. This storm system looks just as strong and is taking a slightly more Northward track. I like the temps at 70 and Dp at low 60 range. With the low strengthening as it heads our way the low-level shear will get stronger and I hope the jet streak hits around 3-6 pm timeframe. We should be just SE of the Low. This could make for some good fireworks unless SPC is playing a late April Fools joke on us. I am saying HIGH RISK on next CnvOut for a small area from SE IA/WC IL/NE MO. YES! B)

 

[Chris Foltz]

Looks like this may turn out to be a good day..chasing wise. Degree of low-level shear along with
moist-moderatley unstable airmass suggests that several tornadoes will likely occur...a few of which could be strong and long-lived. The area I'm sticking to is still Mt. Vernon - Vandalia, IL. Is the lack of many posts for this thread due to lack of excitement, or just everyone is out and about? btw - it looks like the storms that are moving this direction now, will be out of this area by early afternoon, which should clean out the debri. [/b]

Have a feeling quite a few of the regulars were chasing out in western OK today and are probably sleeping it off by now. I'm pretty excited about the possibilites for Sunday personally. I'm currently targeting an area from COU-UIN-STL. In other words, more NE/E MO which will be a little closer to the surface low and a little quicker to clear out from the morning convection.

http://www.wxcaster.com/modelskewt.php3?mo...STATIONID=_kstl

WRF-NMM breaks out precip around 20z in a line from IRK to just west of COU. It rapidly forms into a solid line on the northern fringe by 22z while the southern portion remains discrete for a longer period of time (if you believe model output of simulated radar reflectivity). Regardless, the combination of insolation and strong vertical shear should set the stage for a pretty significant tornado outbreak. Storm motion appears to be a bit more manageable as well coming in around 40kts. Will be anxious to see how things look in the morning once the RUC takes over.

 

[Doug Raflik]

Based on a loop of infrared sat., it doesnt look like clearing is going to be an issue. Fair conditions are already pushing into MO from the west. 09Z RUC has 60° dews stretching into extreme SE IA and western IL at 21Z. I am leaving for Mcomb, IL and will readjust as needed. Have fun everyone.

Doug Raflik
920-210-3771

 

[Kevin Askew]

My model guidence is showing SEMO area along I-55 corridor being best spot to set up. DP's in Poplar bluff area already in mid 60's. Very high EHI values may be a bit influenced by CAPE # but we have had alot of good days with these #'s. Probably we will set up around Poplar bluff to Sikeston MO. Good luck to chasers & stay safe.

 

[Bill Schintler]

Chase target:
Ottumwa, IA

Timing:
Storm initiation 3 PM CDT.

Comments:
Supercell storms with hail to 1.5â€￾ and isolated tornadoes.

Discussion:
Lead impulse within high-amplitude trough – the same one responsible for the severe WX in KS/OK/TX yesterday – has resulted in a round of widespread precipitation and storms in IA/IL/WI, which is currently exiting the area to the east. At 14Z, a SFC WF extended from eastward from low pressure near HJH along a LWD/IRK/STL line in MO. To the south of this boundary a moist and increasingly unstable airmass is in place, and this front will surge northward during the afternoon, reaching a DSM to BRL line by 18Z. Warm sector MLCAPEs will easily exceed 2000J/kG in areas where anticipated partial clearing takes place. Additionally, locally impressive hodograph curves will be in place near this boundary with a SSWRLY 40kt LLJ on top of backed 10kt SERLY SFC flow. This should support an environment conducive to rotating updrafts, as cloud bases will be in the 400m AGL range.

- bill

 

[SteveCarter]

Leaving Mt. Vernon, IL, and heading slightly westward, and a north. Looking good here now..the sun is out, and the temps and dewpoints are starting to rise. Setting up between Litchfield and Jerseyville, IL. Latest models looking GREAT...even the weather channel has their own "greatest risk" special area now. Good luck all, and Ken H...keep the updates coming for me!! thanks!

 

[HAltschule]

While I agree that there is a big severe weather threat today in MO, I don't see enough directional shear to warrant the long-lived, strong tornado expectation you mentioned. Sure there is some speed shear but directional shear does not appear 'that' great based on wind profilers in the area. In fact, the is some backing of the wind at mid-levels. This setup looks more likely to be a solid line of raidly moving storms with Bow Echoes, wind damage and hail the main threat. The tornado threat is there, but the setup does not scream tornadic supercells IMO.