29 Using UW-Cloud Top Cooling Rates in Convective Storm Warning Experiments

Monday, 5 November 2012
Symphony III and Foyer (Loews Vanderbilt Hotel)
Wayne F. Feltz, CIMSS/Univ. of Wisconsin, Madison, WI; and J. Sieglaff and L. Cronce

The University of Wisconsin Cloud Top Cooling (UW-CTC) rate algorithm was developed to monitor vertically growing convective clouds using geostationary satellites. The UW-CTC algorithm combines GOES infrared window brightness temperatures, GOES cloud mask, cloud phase, and visible optical depth retrievals to diagnose cloud-top cooling rates of newly developing convective clouds. The UW-CTC rates for each developing thunderstorm for 34 6-hour convectively active periods over the Central US during 2008 and 2009 were compared to future NEXRAD observations (e.g.- composite reflectivity, Vertically Integrated Liquid (VIL), Maximum Expected Hail Size (MESH), and Echo Top Heights). The relationships between UW-CTC rate and future NEXRAD observations indicate there is relationship between more intense cloud-top cooling rates and more intense precipitation cores compared to weaker cloud-top cooling rates. For example, strong UW-CTC rates corresponded to 55 dBZ composite reflectivity and 1.00 MESH (median values), while weak UW-CTC rates corresponded to 45 dBZ composite reflectivity and 0.60 MESH. The UW-CTC rates have been demonstrated at the NOAA Hazardous Weather Testbed for the past 4 years and at the Milwaukee-Sullivan National Weather Service Forecast Office/UW local testbed for 3 years as part of the GOES-R Proving Ground. The 2012 focus within these testbeds was to apply the findings of the UW-CTC rate versus NEXRAD study. The utility of UW-CTC rates (and associated validation study) when used by experienced forecasters, in combination with synoptic/mesoscale context has been shown to potentially increase severe thunderstorm warning issuance within these testbeds, even in regions well covered by NEXRAD. This presentation will focus on the relationships found between UW-CTC rates and future NEXRAD observations, including a lead-time analysis, as well as how NWS forecasters are using UW-CTC rates within experimental programs (such as NOAA HWT, AWT, and local NWS MKX/UW testbeds).
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