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Satellite-based Nowcasting and Aviation Program

Convective Initiation Research

GOES East Convective Storm Monitoring and Nowcasting Products
GOES East Convective Storm Monitoring and Nowcasting Products

Geostationary satellites provide observations of developing thunderstorms at high temporal and spatial resolution.  Convective storm initiation, the process where a cumulus cloud evolves from an immature "fair weather" state to a mature cumulonimbus, is evident in satellite imagery before it can be observed by operational weather radar.  Numerical weather prediction models often have difficulty in accurately forecasting the timing and location of convective initiation.  Thus, geostationary satellite imagery is an essential dataset for nowcasting the timing and location of future thunderstorm development.

The University of Wisconsin convective initiation (UW-CTC) product is a 24-hour automated algorithm that aids thunderstorm monitoring and nowcasting. Sequences of GOES East multi-spectral IR imagery are used to develop products that can objectively identify developing cumulus clouds in a pre-convective state.  Based on research by Roberts and Rutledge*, cloud-top cooling rates are computed using a box-average method for pixels identified with a cloud microphysical type of liquid water, super-cooled water, mixed phase, or ice. When a cloud-top transitions to the thick ice phase, it is likely the cloud has begun to significantly precipitate indicating convective inititation has already occured.

The UW-CTC products suite can aid the forecaster in objectively determining where convection is occuring. Future severity of these developing storms can be predicted when a forecaster focuses on wind shear and stability parameters in the surrounding environment. Through rapid identification of cooling clouds, the UW-CTC product suite can help the forecaster increase lead time in the watch and warning process.

These products are currently being evaluated by the National Weather Service forecast office in Milwaukee, WI, the Storm Prediction Center (SPC), NOAA/NESDIS Satellite Applications Branch (SAB), and the FAA-supported Aviation Weather Research Program (AWRP) Convective Weather PDT. More information about these products can be found on the the GOES_R Proving Ground Convective Initiation Nowcast Products description page.

GOES-12 Imager derived Cloud Top Cooling (CTC) from June 17, 2009 preceeded the NEXRAD radar based convective initiation signal by 37 minutes.

 

This research is supported by the NOAA GIMPAP and GOES_R Proving Ground (GOES-R Proving Ground) initiative.

 

References

*Roberts, R. D., and S. Rutledge 2003: Nowcasting storm initiation and growth using GOES-8 and WSR-88D data. Wea. Forecasting, Vol. 18, Issue 4, pages 562-584.

Sieglaff, J.M., L.M. Cronce, W.F. Feltz, K.M. Bedka, M.J. Pavolonis, and A. Heidinger 2010: Nowcasting convective storm initiation using box-averaged cloud-top cooling and microphysical phase trends. Submitted to J. Appl. Meteor. Climatol. January, 2010.