The Use of Multiple GOES Sounder Water Vapor Channels to Monitor the Evolution of Mid-level Dry Air in Northeastern U.S. Convective Events

The majority of National Weather Service (NWS) forecaster training for hazardous weather operations has been traditionally focused on radar and model data interpretation. However, the opportunity to integrate satellite imagery and derived products in the convective warning decision-making process will be easier in the Geostationary Operational Environmental Satellite - R series (GOES-R) era. Not only will meteorologists be able to visualize phenomena as they are happening with GOES-R, but the increased number of spectral bands on the Advanced Baseline Imager will allow for better detection and understanding of four-dimensional atmospheric processes. For example, elevated mixed layers, which are characterized by warm and dry air, have a well-documented history of leading to favorable conditions for the development of significant severe weather. The low-level water vapor band (7.34-µm) on GOES-R will be able to detect and track this warm and dry air as it propagates away from its source region. Incorporating traditional midlevel and upper-level water vapor imagery analysis with the ability to analyze these low-level features with the new 7.34-µm spectral band will allow forecasters to link upper-level and low-level atmospheric conditions better than ever.

In anticipation of the launch of GOES-R in March 2016, the NWS has made it a top priority to have its forecasters participate in GOES-R user readiness by using proxy imagery and products in forecast operations. For example, the three spectral bands (7.5, 7.0, and 6.5 µm) dedicated to sensing atmospheric water vapor on the GOES Sounder can be used as a proxy for GOES-R. Currently, GOES Sounder imagery is not often used by NWS meteorologists for decision making because the imagery is only available every hour at a nominal resolution of 10 km. However, even at these low temporal and spatial scales, the GOES Sounder 7.5-µm imagery can prepare meteorologists for GOES-R while being useful in identifying low-level water vapor features. Another GOES-R proxy dataset is synthetic imagery from the 4-km NSSL WRF-ARW model. Synthetic imagery at 7.34 µm emulates one of the water vapor channels that will be available on GOES-R and allows for an efficient visual comparison between the model output and the observed GOES Sounder imagery. Forecasters can utilize these forecasts to understand the features that can be identified in the 7.34-µm band which in turn will help them prepare for the new imagery on GOES-R. The purpose of this applications-based research is to demonstrate how using multiple water vapor bands could have assisted operational meteorologists during three northeastern U.S. severe weather episodes while emphasizing the importance of the three water vapor bands at high spatial and temporal scales once GOES-R becomes operational.