Simulated Imagery and Nearcast in MN/WI

Given the slight risk in and around Minneapolis Center, we've been keeping an eye on the area for convective development later this afternoon. The WRF Simulated IR, as shown below in Figure 1, showed some development over IA late in the morning with more significant development just NE of Minneapolis by 2000 UTC.

Figure 1. 20130821 1300 - 2300 UTC WRF simulated IR imagery

Now take a look at the NAM Nest IR in Figure 2.

Figure 2. 20130821 1300 - 2300 UTC NAM simulated IR imagery

The NAM indicates the same convective development near Minneapolis, but further NE into WI and the upper Peninsula of MI. It also suggests initiation occurring closer to 2100 UTC.

Figure 3. 20130821 1300 - 2200 UTC Nearcast Theta-E (from the 13Z run)

To try and narrow down where precisely this convective may fire, the Nearcast theta-e was evaluated (Figure 3). Two areas of instability, over northern WI/MI and NE IA/SW WI, indicate that convection would perhaps have a better chance of firing within these areas should the environmental set-up be conducive. So, at this moment it appears that the NAM, with convective firing further NE, may be the more correct forecast.

Whether either forecast will verify, however, will be highly dependent on the current cloud cover. Neither of the modeled satellite imagery datasets did particularly well on the initial cloud cover over MN and IA, and it may be that this impacts the overall performance, as well as the chance for convective development in these areas.

For now, we wait and see...