# Adapting Satellite Soundings for Operational Forecasting within the Hazardous Weather Testbed
## 3 Results
### Utility of NUCAPS for Predicting Severe Storms  
Figure 3 shows how useful forecasters found the four NUCAPS products at the end of each day. The regular and modified profiles were the highest rated. Generally, most forecasters said both regular (57%) and modified soundings (69%) were helpful (e.g., \"Somewhat\" and 'Very helpful) rather than not helpful (e.g., 'Not' and 'Not so' helpful), although few ranked it as 'extremely' helpful. Unlike geostationary data which has frequent observations, low-earth orbit satellites only have two overpasses a day over midlatitudes and there are coverage gaps between swaths over regions of CONUS that are south of 33 \({}^{\circ}\)N. The strength of NUCAPS is the availability of environmental soundings during the crucial early afternoon period, just before deep convection often develops, and in between routine radiosonde launches. Given that only a single, 1:30 PM local time overpass was available to the forecasters in the HWT, the moderate evaluations are promising. This outcome was expected, because forecasters synthesize a variety of datasets (e.g., model, satellite, radar, observations) to analyze the environment and make decisions on warnings. In addition, past HWT experiments revealed NUCAPS was used as a component of forecaster analysis to diagnose the environment and assess situational awareness (i.e., are thunderstorms likely or not likely to develop) rather than an independent tool to interrogate. In Figure 4a, we found that one out of 10 forecasters answered yes when asked \"Did you use NUCAPS products as a component in your decision to issue a warning or Special Weather Statement?\" Since the baseline NUCAPS soundings are already operational, we were interested in knowing how NUCAPS was integrated with more sophisticated analysis. In total, 90% of forecasters used NUCAPS with other datasets, primarily radiosondes (Figure 4b). However, NUCAPS was also extensively used with models and radar. In their written survey responses, forecasters stated that they used the RAP and HRRR the most, while 16 percent used other satellite products from GOES, which consisted of the AllSky LAP (an experimental blended model-geo satellite observation product), visible and IR, as well as TPW and RGB imagery to distinguish moisture and clouds. Note that since the testbed involved live forecasting, there was significant variability in the number of severe storms tracked. When comparing the sounding products (Figure 5), more forecasters used the Modified NUCAPS (36%) over the baseline NUCAPS (25%). Recall from the data section, a limitation of baseline NUCAPS is the boundary layer representation; the Modified NUCAP adjusts the boundary layer with surface observations. Below 850 mb, baseline NUCAPS retrievals can have an RMS error of 2 K and 20%, for temperature and water vapor mixing ratio, respectively, while still meeting product requirements [30]. More typically, validation studies have identified a bias of \(-1.5\) K and 15% in moisture over land during the daytime [19; 23]. The greater utilization of Modified NUCAPS in Figure 5 is consistent with qualitative survey questions and written descriptions, where forecasters corroborated  
Figure 4: Reponses to the question (**a**) “Did you use NUCAPS products as a component in your decision to issue a warning or Special Weather Statement?” and the question (**b**) “Which product(s) factored into your decision process?”. Figure 3: Responses to “How helpful were the following NUCAPS products to making your forecast(s)?”. mid-level and higher retrievals with radiosondes but found the baseline boundary layer inadequate at times. These results show that the boundary layer needs further improvement to increase value to a forecaster. NUCAPS-Forecast made its first appearance in the 2019 HWT and showed skill in predicting convective initiation and evolution for 19 out of 28 forecasters (Figure 6).