IN SEARCH OF TORNADOES

Strong to severe thunderstorms are expected over the upper Midwest this afternoon and evening. SPC has maintained its moderate risk outlook (level 4 of 5) for much of Iowa north of HWY 20. An enhanced risk (level 3 of 5) covers my area from the Quad Cities NW. To be clear, the greatest potential is just NW of my area, but severe weather is still a real concern in the NW half of my region with any storm that goes up later today or this evening.

In the hatched area below, SPC indicates a 10-30 percent chance of a tornado within 25 miles of a point. Additionally, there is a 10 percent chance of a significant EF2 or greater tornado.

This is the morning discussion from SPC regarding the threat.

   A regional severe weather outbreak still appears possible across the
   Upper Midwest, with a threat of strong to intense tornadoes, very
   large hail, and swaths of damaging winds.

   Convective line ongoing across central MN is expected to continue
   quickly northeastward through the region, leaving ample time for the
   warm front to progress northward and bring a warm, moist, and
   unstable airmass into the region ahead of the dryline. Thunderstorm
   initiation along the dryline is forecast to begin around 18-20Z near
   the SD/MN/IA border intersection vicinity, before then continuing
   quickly eastward across southern MN and northern IA throughout the
   late afternoon and early evening. Volatile environmental conditions
   are expected south of the warm front and east of the dryline, with
   strong instability (MLCAPE near/above 3000 J/kg) and deep-layer
   shear, and a persistently intense low-level jet that will maintain
   very favorable low-level shear/SRH. 

   This environment will be conditionally favorable for long-track
   supercells with strong/intense tornado potential if a discrete mode
   can be maintained. Quick upscale growth into a more linear or
   cluster mode is possible, but the vertical shear appears strong
   enough for a discrete mode to be maintained as well. A scenario
   where a primary line develops with discrete storms ahead of it is
   possible as well. In any case, the overall environment supports the
   potential for large to very large hail, damaging gusts, and strong
   to intense tornadoes with any discrete storms. Line-embedded
   tornadoes and strong gusts are possible within any convective lines.

   A more conditional scenario exists farther south from central IA
   into northeast KS/northwest MO. Here, the kinematic environment will
   remain supportive of supercells capable of all severe hazards, but
   capping could prove detrimental to deep convection given the weaker
   low-level convergence and large-scale ascent. Any supercell that can
   initiate and be sustained could become long-tracked within the
   expanding and very favorable warm sector, posing a threat for strong
   to intense tornadoes and very large hail.

Myself, I am on the road chasing with the goal of intercepting a storm as the dry line punches into the instability later today somewhere over NC Iowa or near the Minnesota border. I will attempt to keep you informed of what I see if conditions warrant. Keep an eye to the sky and roll weather...TS