This is an update to a previous blog post – Missing ASOS Observations during Hurricane Irene across eastern NC, VA, and MD
Several NWS Service Assessments including those for Hurricanes Isabel (2003), Charley (2004) and Katrina (2005) noted that ASOS units are vulnerable to failure during tropical cyclones. In addition to the obvious threat from damage and destruction from the wind and windblown debris, the observations and the archive of observations can be lost because of commercial power and telecommunication outages. The missing data is important to operational forecasters, emergency managers, the research community, insurance companies, and others.
The NWS has been working with the FAA and others to provide standby power to the ASOS DCP/sensor group along with the ACU for 72 hours when commercial power is lost. This should provide a window of time for technicians to recover critical observations from the ASOS archive after the passage of the tropical cyclone. Note that while standby power will help preserve the ASOS data archive for a few days, in many instances, it may not mean that data will be transmitted for real time use.
Recently technicians installed a generator at KRWI, Rocky Mount-Wilson Regional Airport in Nash County NC. This marked the 8th site in North Carolina to either receive a generator or identify another stable power source sufficient to provide backup power.
The map below, developed from a base map obtained through the NC State Climate office CRONOS display, shows the locations of ASOS platforms across the Southeast. The map has been augmented with color coding that shows which ASOS units have had a generator installed (yellow), have obtained access to on site standby power (blue), and locations where a generator is planned (green). It is possible and even likely that additional sites have access to on site standby power, but that information was not available to the author.