Using simulated ABI satellite imagery and UWCI nowcast product to produce 21z and 23z >40 dbz echo probability snapshot forecasts

Simulated band 13 forecasted ABI satellite imagery for 21z (bottom) and 23z (top) 02 June 2010.(Apologies for the backwards times)

This morning in the aviation focus group at the HWT, I encouraged the use of simulated ABI satellite data to guage an idea of the location of > 40 dbz echos initiated after 18z by the NSSL-WRF. Comparison of 14z B13 simulated ABI data to realtime GOES infrared imagery showed a fairly accurate representation of both intensity and location of the remnants of last night's MCS that moved through IA/northern IL, at the time extending from central MI through northern OH. However, second MCS remnants over northern MO were absent in the simulated data (See WV imagery in previous post). Therefore the outflow boundary and cold pool from the second MCS was not accurately captured by the NSSL-WRF and resulted in the suppression of convection along the weak cold frontal boundary that extended from east-central IL southwestward through MO / KS / western OK until 23z. One large positive result was that the NSSL-WRF did suggest initiation of convection along the outflow boundary from the then MI MCS along the KY/IN border by 21z.

The large stable cold pool that was left over central MO led us to forecast a moderate probability (50-74%) of thunderstorm initiation along the outflow boundary from the morning MO and MI MCSs along the MO/AR and MO/IL/IN/KY borders in agreement with the simulated ABI satellite data from the NSSL-WRF. Even though the simulated imagery wasn't particularly accurate in its evolution of the MO MCS event, the simulated mid-level water vapor channel (B10) was useful in identifying the location of mid-level vorticies over the southern plains and gulf coast during the forecast period. It was one of many tools that was taken into consideration when issuing a slight and moderate probability of convective initiation (> 40 dbz tops) over west-central TX and also over the LA/AL gulf coast for both the 21 and 23z 02 June snapshot forecast periods. As I'll make mention of below, convection in TX was initiated by 20z in the simulated satellite imagery which was at approximately the same time as realtime initiation. The complex appears to be evolving into an MCS as the evening progresses.

During the afternoon updates, the aviation team relied fairly heavily on developing trends in ongoing initiation over western TX and the southeast US as a whole for forecast modifications. We looked extensively at the performance trends of the UWCI nowcast between 18 and 20z. The algorithm performed very well and captured explosive convection over western TX with ~15 minute lead time. The convection was associated with a low-level meso-vortex dynamically supported by a sharp shortwave ejected from the AZ/NM border out over the southern plains shortly after 18z. Real-time water vapor and visible satellite imagery was critical in locating and tracking this feature from 13z onward.

A final thought, Aviation Weather Center (AWC) forecasters Steve Silberberg and Bruce Entwistle discussed with me their strong interest in installing the UWCI, CTC/OT, and simulated ABI imagery products in NAWIPS at their facility and I said I would relay their request to Wayne, Jordan and others.

-Dan Hartung