CIMSS Nearcasting: Pushed to the limit - the lower limit!

The past three days have been challenging for the CIMSS nearcasting model since atmospheric conditions have not been favorable for the development of strong convection.  Ɵ_e lapse rates have rarely exceeded 8-9 dƟ_e.  However, forecasters have been able to use the nearcasting guidance, both Ɵ_e and the new CAPE products to correlate where convective development is expected.

 

Shown below is a 4-hour nearcast of dƟ_e  and CAPE valid 22UTC, May 16, 2012.  The nearcast model consistently placed a line of instability along the Ohio River Valley associated with a trailing weak cold front.  At this time convective cells formed in NE Arkansas which matched well with the nearcasted dƟ_e and the nearcasted CAPE.  Also shown below is the verifying GOES IR and radar images.  Although convective cells formed, they were not expected to become severe based on other available guidance.