The Storm Prediction Center has a large portion of the Western Corn Belt highlighted in a slight risk for today.  As always, ChaserTV remains your destination for extreme LIVE storm chase video.  Stop by often to see what kind of activity is ongoing today and don’t forget to follow us on Twitter for regular updates regarding active streams We’re also on Facebook, so you can stop by our page there for updates if the event evolves as forecast today.

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Forecast Synopsis

While considerable uncertainty currently exists regarding the magnitude, extent and evolution of today’s severe weather threat, courtesy of overnight convection across IA that was not handled so well by last night’s 00z suite of model runs, shear profiles would suggest that at least some heightened severe weather threat exists today across the Western Corn Belt.  The Storm Prediction Center has the area outlined in a slight risk, though the earlier moderate risk was rescinded due most likely to uncertainty regarding instability and frontal placement in the wake of the previously referenced MCS.

As a quick overview, an entrenched zone of westerly flow will contribute towards promulgating a series of mid level shortwave disturbances across the Midwest early this week, with an active convective day still possible this afternoon.  Morning RUC guidance remains consistent with last night’s 00z suite of model runs in propelling a belt of H25 flow on the order of 100 kts across the Northern Plains and Upper Midwest, with the nose of this H25 jet maxima reaching the far western cornbelt by 21z Monday.  Associated with this rather robust H25 flow will be H5 winds on the order of 40-50+ kts as the shortwave progresses east, with a fairly catawampus contour progged on the 500 mb height forecast.   H85 winds progged to be on the order of 30-45kts will help to propel warm and humid air into the region, as a fairly stationary surface front may lift northward between US34 and I80 on Monday; however, the eventual location of the front will be affected by several areas of ongoing convection across SE as well as NW IA.  Surface winds INVO the frontal boundary will remain on the order of 10-20 kts.

The extent of instability following this morning convection is still somewhat uncertain, but current visible satellite guidance does show a persistent area of clearing aross the entire SW portion of IA into far NW Missouri, and this may spread eastward with time.  If the area is indeed able to recover from overnight convection, model guidance is suggesting that respectable instability (SBCAPE AOA 2,000 J/KG), coupled with remnant OFBs, ample wind shear (SFC-500 mb bulk shear values of 40-50 kts) and SB LI <-4 to -8 C will promote an environment ripe for deep convection by early afternoon.  The most likely scenario is for a few discrete supercells to form across SW or W IA before quickly congealing into a MCS with a significant risk for damaging winds >60 kts, large hail >1.00″ and possibly tornadoes, either with any discrete cells early in the evolution of this event or as transient spin ups associated with moving bow echoes.  This MCS should propagate ESE along the instability axis, perhaps reaching far N MN and W IL by far SE IA by 02z-03z TUE.

However, given magnitude of uncertainty in the wake of overnight convection, the area of clearing to the south will be one to watch today.  If the convective environment can recover as model guidance, including the RUC suggests, their is still an appreciable severe threat today.

JLR