EWP Blog

The Hazardous Weather Testbed (HWT) provided an excellent opportunity for forecasters to work side by side with researchers to evaluate radar technology and warning strategies developed for future use.  While participating in the experiment, I had the opportunity to evaluate the Phased Array Radar (PAR) and the Collaborative Adaptive Sensing of the Atmosphere (CASA) radars in both a real-time and archived environment.  Our group also tested the new experimental process which integrated short-term severe threat probabilities into operational severe thunderstorm and tornado warnings.  The outcomes of the experiments demonstrated potential significant advantages and challenges if implemented into an operational weather forecast office (WFO) setting.

My experiences with the PAR radar equipment were very positive.  This technology will likely exceed the capabilities of the current WSR-88D radar network.  The primary advantage to using the PAR radar technology is the rapid update of base radar data.  During the experiment, I was able to rapidly identify important convective structural features that led to quicker warning decisions and longer warning lead times.  Another important advantage of the rapidly updating PAR data was the ability to identify important storm features in the 1 minute PAR data that would not have been sampled by the 5 minute WSR-88D scans.  In addition, the 1 minute update PAR data better portrayed storm evolution.  This was particularly advantageous during an archived unorganized pulse severe thunderstorm event which we used the PAR radar to conduct warning operations.  As a warning decision maker, I was able to observe the initiation of collapsing cores aloft and issue warnings with enhanced lead time.  The current scan limitations of the WSR-88D likely would have further delayed my decision to warn during this event.

Advantages of the PAR radar exceed any limitations that I experienced.  The only minor limitation to the PAR radar will be the ability of the radar operator to adjust to the much faster influx of additional radar data.  I think this will primarily be an initial challenge which will be overcome quickly by warning forecasters.  In fact, I felt comfortable with the increased radar data flow after a few days of use.  Overall, my experiences using the PAR radar were very positive and I hope that this technology will eventually be implemented into the NWS field offices.

Another radar system which we experimented with was the CASA radar network.  The CASA radars also proved to be a robust network that provided advantages to warning forecasters during experimental warning operations.  As is the case in most NWS County Warning Areas (CWA) and in the Memphis CWA, sampling low-level storm characteristics using the current WSR-88D radar network at extended distances from the radar is very difficult or impossible due to radar spacing issues and curvature of the earth.  This greatly limits warning forecaster’s ability to observe important low level storm at large distances from the radar.  The greatest advantage that I see to implementing the CASA radar network is the ability to limit gaps in low-level radar coverage.  This will provide warning forecasters with improved radar information necessary for longer lead time and improved warnings.  In addition, enhanced low level radar information allows warning forecasters to better define geographically where the greatest storm threats exist.  While participating in the HWT, I experienced these benefits firsthand.  The CASA network would likely be best implemented as a compliment to the PAR radar network.  By locating CASA radars in between the traditional PAR (current WSR-88D sites) radars, the system would become very robust and most beneficial to the NWS warning process.

The HWT also tested the capabilities and practicality of probabilistic warnings.  Probabilistic warnings appear to present the greatest challenge of all the new techniques tested.  Researchers envision probabilistic warnings eventually replacing current NWS warning practices.  As a forecaster using the new probabilistic warning technique, I found the process difficult to employ and likely confusing to the public.  The primary limiting factors of probabilistic warnings in my opinion include, (1) quantifying specific threats and expressing those threats in a proper manner to the public, (2) warning forecaster work load issues, and (3) public response problems associated with different threat percentages.  The NWS mission statement clearly reflects the important role that severe weather warnings play in protecting life and property.  The primary reason that the NWS issues severe weather warnings is to encourage the public to take actions required to protect themselves from dangerous weather.  I believe that eliciting public response to probabilistic warnings will be a significant challenge since every person’s threat threshold is different.  Probabilistic warnings may create confusion and limit public response to warnings and should primarily be available only to very high end users (if they can understand the process and find it beneficial).

Overall the HWT was a great opportunity for me to evaluate potential NWS technology of the future.  Collaboration between researchers and operational forecasters is a great way to share ideas, provide feedback, and get useful technology into NWS field offices.  The HWT and similar collaborative experiments hopefully will continue into the future.  I look forward to the eventual release of new and improved technology into the field.  Finally, I would like to thank those involved for giving me the opportunity to participate in this experiment and hope to again be involved in similar projects in the future.

Jonathan Howell (NWS Memphis TN – Week 4 Participant)