Unique role of simulated satellite imagery in severe weather forecasting

This week has been very challenging for all forms of 6-12 hour probabilistic forecasting, primarily for QPF and convective initiation. The general mesoscale setup at 12z each day has been at least one (and in a couple instances multiple) remnant MCS complexes over the CONUS domain from the prior evening, each of which had its own unique outflow boundary that was not captured in both determinate and multi-member ensemble runs initialized at 00z. Since the CIMSS simulated ABI imagery from the NSSL-WRF is initialized at 00z, it has predominately missed the development of these MCS systems and attendant boundaries as well. That being said, the simulated imagery has not been found useful when trying to determine where and when convection will initiate during the subsequent forecast period primarily due to a lack of skill in predicting the existence and evolution of remnant mesoscale boundaries.

On a more positive note, Chris and I convinced the aviation and severe teams to use the simulated low to mid-level water vapor imagery to identify the structure and location of the remnant surface meso-vortex in TX shortly after 13z 02 June. A closer look at bands 8 and 9 also nicely showed the evolution of the upper level trough / ridge pattern and wind fields that were not immediately identifiable on the standard 250 hPa chart at 12z 03 June. Probably the most important positive outcome of the week thus far with the simulated satellite imagery is that forecasters have found the simulated WV imagery (B10) to be a helpful tool in narrowing down the noisy 500 hPa vorticity field to identify important vorticity signatures and regions of wind shear that could be sufficient to dynamicaly force / support convective initiation during the present forecast period.

They also said it would be helpful if the CIMSS simulated imagery were available from 12z onward instead of the current 17z time period to eliminate having to toggle back and forth with the CIRA simulated imagery currently being used to verify any morning boundaries that the NSSL-WRF 00z run captures.

-Dan Hartung