Brian C. Carcione
Penn State University
It has been said that "time flies when you're having fun." The old adage has never been more true. Between May 29 and August 14, 2001, I spent two days a week at the National Weather Service Office in Old Hickory, Tennessee. While few other experiences in my life have been as rewarding, certainly no other experience has coupled education with entertainment so well.
As with any experience, there's usually a pretty distinct difference between what you expect and what you end up with. When I opened the door to the office that first day, I honestly didn't know what to expect. However, my mind turned to the few things I knew about the Weather Service and what it did: zone forecasting and severe weather warnings. Two and a half months later, when I opened the door to leave for the last time, I had gotten a very different but much more complete picture of the people who worked there as well as what they did. Yes, there was zone forecasting, and the severe weather warnings (plenty of warnings indeed), but there was aviation forecasting, upper-air observation, hydrology, computer work, and in-house training. This experience taught me quite a lot about what lies beyond the 400-level meteorology classes.
Severe Weather & Mesoscale Meteorology
Severe Weather & Mesoscale Meteorology
It's hard to talk much about the summer of 2001 in Tennessee without talking about the unusual amount of severe weather that the region experienced. The worst part of the season is usually in April and May, when the jet stream is making its way back north and it seems the weather can't decide whether to be warm or cold. Such conditions were in place for the famous downtown Nashville tornado of April 16, 1998 and the "Super Outbreak" on April 3, 1974. However, the spring of 2001 had been a relatively calm season, with a few "minor" outbreaks but nothing major. As I began work at the end of May, it was assumed that the bulk of the severe weather season was out of the way.
My second day at work, May 31, proved that severe weather did not follow the calendar. A line of very strong thunderstorms was crossing the Mississippi River at the time I arrived and was rapidly crossing the countryside of West Tennessee. As the day shift handed off to the evening shift, the storms appeared to be getting stronger. The NWS in Memphis was issuing warnings as the line approached the Tennessee River, which was roughly the western border of Nashville's area of responsibility (called a CWA, for County Warning Area). The storms crossed into our area, prompting the evening shift to issue severe thunderstorm warnings for the western counties. While Jerry and Sam, meteorologists on that shift, analyzed and examined the storms with radar, I privately fought to contain my excitement. Severe weather my second day, and I was there to witness the behind-the-scenes action!
My excitement changed to concern before long. The storms seemed to be strengthening still, and they prompted the Storm Prediction Center (SPC) in Norman, OK to issue a severe thunderstorm watch. Damage reports were coming in from around the region, with wind damage and hailstone sizes having reached severe limits. But the worst event of the afternoon and evening came when AWIPS, the computer system, flagged a storm entering rural Cannon County as having rotation. The radar clearly showed rotation indicative of a mesocyclone, or supercell; the question was, would it produce a tornado? A severe thunderstorm warning was issued, but they held off on the tornado warning. There was more rotation in another part of the line and someone on the "HAM" amateur radio reported a funnel cloud; a tornado warning was issued for that storm, but no damage was ever reported.
Since I had no real experience in dealing with or identifying severe thunderstorms and thus couldn't help the warning effort, I was asked to play a different role. Jerry gave me a thick binder filled with contact information for all of the counties in the warning area and told me to call emergency management offices. At the same time, a certified amateur/HAM radio operator was requesting public storm reports from other radio operators. As time went on, reports starting coming in that there was severe damage in the tiny community of Auburntown, which had been right in the path of the supercell in Cannon County. When I got home late that night, the local news was reporting that a tornado had touched down in Auburntown, and one man had lost his life, and his pregnant daughter was injured.
Another memorable event came more than a month later as the country got back to work after the Independence Day holiday. I awoke on July 5, 2001 to see a series of severe thunderstorms, many of which were showing rotation. One cell prompted the weather service to issue a tornado warning; the storm kept its severity to the point where they issued the tornado warning for three counties in a row. Perhaps the most amazing thing about this was where the rotation was occurring. The various "Stormtracker 8000" and "Skymax 4" doppler radar systems on TV were zoomed down to street level, and they were identifying streets that I used to get to the weather service office all the time! But the drive to work was uneventful, and fortunately there was no tornado; however, the anemometer on the hill recorded a peak gust of 61 miles per hour. More tornado warnings were issued that day as the line made its way from northwest to southeast, but fortunately, nothing as serious as Auburntown would be repeated for the rest of the summer.
Along with the tornado warning on July 5, there was the "ghost tornado" of August 2nd. It had been an ordinary, run-of-the-mill August day, with the usual pop-up, so-called "garden variety" thunderstorms. It was my turn to work with the upper-air balloon launch; as we returned from the launch and monitored the balloon's ascent, Mark, one of the forecasters on duty that night, said, "Nick, tornado warning, Maury County." Nick, the hydrometeorological technician on duty, probably thought it was a cruel joke, as did I. But a closer examination of the 0.5-degree reflectivity product from the radar on AWIPS showed a clear, classic hook echo indicative of a tornadic thunderstorm; the storm-relative velocity scan showed an equally-impressive inbound-outbound couplet. Even worse: the storm seemed to be headed directly for the heavily-populated county seat of Columbia. As the TV news covered the seemingly random warning, we monitored the storm as it kept its intensity and then morphed into a bow echo and then dissipated. While we were looking back at the radar data (it was a good, fast call; the computer flagged the storm more than a minute after the warning was issued), we got the strangest reports from the spotters in the county: absolutely nothing. Aside from heavy rain and a tree down here or there (verifying the preceding severe thunderstorm warning), there was no damage whatsoever from the storm. These hits and misses made me realize the limitations of technology, as well as how much there was left to learn about severe thunderstorms and tornadoes.
All in all, out of the twenty-five trips I made to Old Hickory, there were five severe weather events. On top of that, there were at least half a dozen events in between the days I worked, probably more. When I was there and working, I was usually manning the phones, making numerous phone calls to sheriffs' dispatchers and highway departments. By getting damage reports, we were able to verify what we saw on radar; these reports ultimately made their way to a central office where statistics were compiled on warning effectiveness.
My preview of Meteo 414: Mesoscale Meteorology was enhanced with more than just real live experience. I was in the right place at the right time and was fortunate enough to get to see Jack Hales speak. Mr. Hales is a lead forecaster for the Storm Prediction Center, and he came to Nashville in mid-July to speak to our office's personnel and regional emergency management staff about predicting severe weather. Most valuable of all was his retrospective analysis of the Auburntown event and the Super Outbreak of 1974. Instead of trying to deal with information real-time, we were able to see the ingredients involved and the situations at a slower pace, with time to reflect and learn what to look for next time. He also went into depth on the synoptic-scale features that could produce severe weather, specifically shear and instability. On top of the lessons from Jack Hales, I accompanied Jerry and then John to two different SKYWARN spotter training sessions. The sessions taught the general public all about thunderstorms and how they formed, and I learned a lot just from these presentations. The added bonus was getting certified as a storm spotter for the first time.
Computers in the National Weather Service
Computers in the National Weather Service
While severe weather may have dominated the summertime, there was always plenty to do and plenty to learn the twenty other times I was there. Definitely one of the most important parts was the "computing" part of the business: how they got their resources, the tools they used to make their analysis and the evolution of the technology involved. The greatest tool they have at their disposal is AWIPS, a program which integrates everything from current lightning data to 72-hour ETA 500mb vorticity maps to a vertical cross-section of thunderstorms. To bring it into perspective, it's like GARP on steroids. While quite a few words were directed at the system's speed, or rather lack thereof during a crisis, the integration of all of the available tools was certainly a distinct advantage. AWIPS was running on five UNIX-based computers, each with three displays, one for text products and the other two to bring up graphical products. By the time I left, another new software program was in the process of being implemented. IFPS, which stood for Interactive Forecast Preparation System, was undergoing changes in preparation for use. The new software promised to revolutionize the weather service and the way they forecast; however, it looked like it would take a long time before it was second-nature to the forecasters. Meanwhile, two personal computers were running LINUX, a variant of UNIX. One of the lead forecasters, interestingly enough, had one of the computers running its own model and producing output that could be viewed in AWIPS. "Workstation ETA" as it was affectionately called, ran a mesoscale version of the popular model that, theoretically, could focus on the terrain and peculiarities specific to Middle Tennessee.
Web Verification Project
Web Verification Project
While I may have been awed by AWIPS and the Workstation ETA, it was a different and much simpler programming project entirely that captured the attention of the people I worked with. Often, in times of crisis, the emergency management personnel and sheriffs' deputies at the county government level are unwilling or unable to worry about damage reports related to weather. Reports from trained spotters were sometimes also difficult to get on demand. The idea, then, was to come up with a list of additional contacts and try to spread them out in an equidistant fashion over the warning area; this way, it would be easier to verify the warnings or get vital information that might be necessary to issue new ones. The project team started compiling lists of "outdoor-related" businesses such as golf courses and orchards.
An even bigger challenge was coming up with a format that would make the database attractive to use. Scott, one of the original minds behind the project, had assigned numbers to hundreds of communities and cities across the northern part of the region. These numbers were on a map that could be easily referenced; for example, if a storm were entering the northwest tip of Williamson County, the forecaster would check the map, see the number 2, check under that number, and have a list of contacts he could call. My role in the project was to make the map interactive. While the project was simple enough, it was quite time-consuming. We decided that the easiest way to get the interactivity was through a local web page, one that only computers in the office could access. So I made a county map for each of the forty-two counties in the warning area and matched up numbers to communities for each county. The HTML allowed the forecaster to click a county and then click the number of the community for the contacts he wanted. Unfortunately, the HTML for forty-two counties with ten or more communities per county was too much for me to handle alone; the project is still in-progress.
Upper-Air and Hydrology
Upper-Air and Hydrology
In addition to all of the meteorology and computer work, Nashville serves as an upper-air station. In accordance with the standard 00Z and 12Z release times, preparation for the balloon launch would begin a few hours before 7pm central daylight time. The hydrometeorological technician (HMT) would prepare the battery, prepare and check the instruments, set up the radio antenna to track the rawinsonde, and enter data into the computer before launching at 6pm central time. The data then had time to accumulate and get into the system before the clock struck 00Z. I feel lucky to have worked at a site that launches a balloon; since only one or two stations per state launch a balloon in the United States, not many people have gotten to watch, let alone help prepare for a rawinsonde launch. I also got to work a limited amount with Mike, the service hydrologist. Ranking right up there with the lesser-appreciated parts of the weather service, Mike's job was to watch the levels of navigable rivers in Middle Tennessee. The forecasters provided the forecasts for rain; in turn, the hydrologist, in concert with the river forecast centers, ran hydrological models to determine the rain and runoff's effect on river levels. Summer isn't a prime season for rain or for river flooding, so my work with Mike was limited.
Finally, last but not least came the forecasting, the aspect of the NWS I thought about first coming in. Interestingly enough, it wasn't even the zone forecasting that made the bigger impact on me, it was the aviation forecasting. Few people in the public would ever realize that the NWS makes specific, coded forecasts for private pilots. In fact, most of the meteorology students aspiring to be forecasters wouldn't think about aviation forecasting either.
Nashville's NWS office prepared two Terminal Aerodrome Forecasts (TAF's) for the Nashville and Crossville airports. Compared to other offices, this was a relatively small number (even State College has four to prepare). The TAF's contain wind speeds, cloud ceilings, and visibilities for a twenty-four hour period. It's these different parameters that required a whole new outlook on forecasting for the person preparing the TAF's for the day. Instead of just looking at 700mb relative humidity fields to get a general feel for how much cloud cover there might be, the aviation forecaster had to get specific about where the clouds would be, how thick they were, and exactly how long they would last. As a result, the forecaster looked at a variety of different products from the models.
I spent much of the summer watching forecasters prepare TAF's, short-term forecasts, and all of the other products. It was all the more fitting, then, that I waited until my last day to get in on the public zone forecasting. The zone forecasts were submitted by 4am and 4pm daily, along with updates around 10am and 8pm. For the 4pm "package" as it was called, I went in earlier than usual, around noon, and prepared for a blitz of models and forecasts. John, the lead forecaster for the day, told me to "strap in."
The most interesting thing about the forecasting process was that it wasn't much different from anything I'd ever done before. Start with the current conditions: satellite loops, radar loops, updated observations for the area, and so on. The big story for that day was the front that had just passed through; instead of the usual dewpoints in the 60's and 70's, dewpoints had dropped into the 50's and precipitable water measurements from the morning balloon sounding had dropped below an inch. From the current conditions, it was onto the usual model output: 500mb heights/vorticity and sea-level pressure to see the general patterns, 700mb relative humidity for cloud cover, 12-hour precipitation, and so on.
At this point, it was John's lunchtime, and he gave me an assignment: begin writing the "AFD," commonly known as the area forecast discussion. The request made me nervous; while the forecast process hadn't been terribly earth-shattering to me, the premise of the AFD was to let surrounding forecast offices know what we were thinking. My nerves came from the fact that my words were going to be read by more people than your normal Campus Weather Service shift notes. Nevertheless, I started writing, starting with the current conditions and then moving on to what the big "forecast concern" was for the day. John came back, and we used a few more varied tools: cross sections to determine where the cloud cover would be at specific times, a model skew-T to determine whether an incoming front would produce thunderstorms. John went over my discussion, adding some things, changing others, and then adding a line at the very end that made me proud: "CARCIONE/GORDON."
My second task as public forecaster was perhaps the most daunting. The meteorologist-in-charge (MIC) had requested a map discussion, and it was my job to provide it. Feeling like a lecturer at Penn State with my laser pointer and computer projector, I took the staff through the satellite and dewpoint plots, then through the ETA model's portrayal of the next few days. A few times I was at a loss for something to say; fortunately, John was there to help pick up the slack. What seemed like an eternity probably lasted only 5-10 minutes, but when I was done, I got a round of applause. Since it was my last day, the event was an opportunity to thank everyone. The MIC, as a gesture of their appreciation, presented me with a "brief-bag" that I will always treasure.
The final task of my time at the weather service was quickly approaching: the 4pm deadline for the zone forecast was near, and it was time to write it all out. We broke up the forty-two county area of responsibility into three groups: one for the main metropolitan area, one for the elevated Cumberland Plateau and its cooler temps, and a final one to delay the effects of the front that was to pass through on Thursday. From there, it was just a matter of rewording forecasts to adjust temperatures and timing; partly cloudy in the southeast part of the area meant that it would be cloudy with showers in Nashville. While this was no small task, John and I finished with time left to spare, and with another end line of "CARCIONE/GORDON," the zone forecast product was issued to the world.
Despite all of the uncertainty and nervousness about the quality of my forecast, the process reinforced what I already knew while adding to my experience. When later shifts wrote in their discussions that "no major changes are needed to current forecast," my confidence in my forecasting grew. The experience made me rethink my stance on whether I was meant to forecast or not. I came back to Penn State at the beginning of the fall semester a changed man, confident in my abilities and ready to take on the responsibility of shift managing for the Campus Weather Service. An added bonus was the pride I took in every product that had my initials or last name at the bottom, whether it was a short term forecast, flash flood statement, local storm report, or the "holy grail" zone forecast. Somewhere, someone was looking at our statements and seeing "BC" at the bottom, and that thought gave me a rush every time.
Through all the forecasting, all the computer work, and all of the severe weather, there were two themes: education and fun. The learning part was easy; I filled a few pages of notes every day I worked. The fun was an added bonus, because it reaffirmed that the fun we were having as students wouldn't suddenly stop as we entered the workforce. Even in the face of storms on that July 5, there were jokes and laughter. As the forecast was being produced on that last day in August, the distinct sound of a Ross Perot imitation was heard. If anything, working at the NWS reminded me that laughter and camaraderie were among the most important parts of the job'not to mention one forecaster's apparent obsession with chili-cheese fries.
All in all, my 150 hours' worth of work at the National Weather Service in Nashville may have been one of the most valuable experiences of my short life. Most importantly, I learned a lot. It was also valuable having a weekly routine and a purpose in an otherwise boring and uneventful summer. I would love to do it all over again.
Finally, I would like to thank everyone I worked with: meteorologist-in-charge Derrel Martin; warning coordination meteorologist Jerry Orchanian; science and operations officer Henry Steigerwaldt, lead forecasters Jim Moser, Darrell Massie, John Gordon, Mike Girodo, and Mark Richards; journeyman forecasters Scott Dickson, Sam Herron, Mark Rose, Jason Wright, and Bobby Boyd; hydrologist Mike Murphy; Mike Davis; hydrometeorological technicians Nick Parrish, Earl King, Fred Hellwagner, and Colin Blackburn. Without their willingness to talk, explain, and teach, this paper would have been a lot shorter'and the summer a lot longer.