Update on ASOS Outages from Tropical Cyclones

Availability of hourly observations and peak wind gusts during Hurricane Irene. Hourly ASOS observations from a 42 hour period from 18 UTC 26 August through 12 UTC 28 August were examined for the availability of meteorological data from the ASOS.

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.

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3 Responses to Update on ASOS Outages from Tropical Cyclones

  1. Bryce Tyner says:

    Thanks, JB for this interesting analysis. Just a few observations/questions:

    1.) When did RWI and Morehead get installed? Was this after Irene? I am surprised at the number of missing observations in these stations, even with ASOS generators installed.

    2.) What is the difference between ASOS generators being installed and on site standby power? I assume this would mean a gap in data coverage in times of outages for stations with on site standby power being available vs. actual generators, but I wanted to make sure.

    3.) It is great that the generators are available in regions with highest wind speed, but disheartening that many of these areas still have missing data points.

  2. Jonathan Blaes @ WFO RAH says:

    Hey Bryce,
    Here are some answers to your questions, at least to the best of my knowledge.
    1) The KRWI generator was installed just a week or two ago. That is what inspired this message. I didn’t know a lot about the generator installations so I asked around a bit. I am not certain about the KMRH installation but would be surprised if it was before Irene.
    2) From what I understand, if standby power was available from some other FAA equipment then the NWS folks tied portions of the ASOS into that power source. For example, an ASOS might be situated near a localizer or some sort of ILS instrumentation that the FAA has for aircraft operations, in that case the ASOS was tied into the emergency power of that equipment. If the ASOS was too far away and power cables or other issues got in the way, then a generator was installed.
    3) I believe they had bigger plans and wanted to install more generators and obtain backup power but budgetary concerns are an issue.

  3. Pingback: Gust Factors from Five Tropical Cyclones Reveal Similarities and May Lead to New GFE Tools | CIMMSE

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