Friday, 26 October 2018: 9:00 AM
Pinnacle room (Stoweflake Mountain Resort )
Intense tropopause-penetrating updrafts and gravity wave breaking generate cirrus plumes that can reside several kilometers above the primary anvil of deep convection. These “above anvil cirrus plumes” (AACPs) exhibit unique temperature and reflectance patterns in multispectral satellite imagery that can be recognized by weather forecasters, especially using 1-min “super rapid scan” imagery. AACPs are evident during significant severe weather events and, due to their importance, have been studied for over 35 years. Despite this body of research, there is uncertainty regarding why some storms produce AACPs but other nearby storms do not, exactly how severe are storms with AACPs versus those without AACPs, and how AACP identification can assist with severe weather warning.
These uncertainties are addressed through analysis of severe weather reports from ground observers, National Weather Service (NWS) severe weather warnings, observations from NEXRAD WSR-88D radars, total lightning observations from a ground-based network, and GOES observations for over 4500 storms observed by GOES super rapid scanning, 405 of which produced an AACP. These datasets are accumulated throughout each storm lifetime through radar object tracking. It is found that 1) AACP storms are much more likely to be severe than non-AACP storms, 2) AACPs typically appear well in advance of severe weather, 3) the majority of severe weather reports, especially EF-2+ tornadoes and 2+ inch hail, are produced by AACP storms, 4) early AACP recognition can provide comparable warning lead time to that provided by an NWS forecaster, and 5) the presence of an AACP can increase NWS confidence that 2+ inch hail will occur. Given that AACPs occur throughout the world and most of the world is not observed by Doppler radar, AACP-based severe storm identification and warning would be extremely helpful for protecting lives and property.
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