As Hurricane Irene was intensifying into a Category 3 storm over the Bahamas, three scientists from the University of Wisconsin-Madison joined NOAA researchers on a “Hurricane Hunter” aircraft flight into the eye of the storm. Lisha Roubert, Chris Rozoff, and Mathew Sitkowski all conduct hurricane research in Madison, Wisc., and traveled to Tampa, Fla., for the flights.
The NOAA Aircraft Operations Center at MacDill Air Force Base had been conducting flights into 
the eye of Irene every 12 hours since Aug. 23. Flights last about 8 hours each, as they make multiple passes through the eye. These passes are made at alternating angles of approach in order to sample the widest possible area of the storm.
During flights, scientists from the NOAA Hurricane Research Division assist in collecting data that are sent back in real-time to the NOAA National Hurricane Center in Miami, Fla. Onboard radar data, flight-level wind speeds, surface estimated wind speeds, and GPS dropsonde data are all extremely valuable to the NHC to initialize models to help improve track and intensity forecasts.
On the afternoon of Aug. 23, Lisha Roubert, a graduate student in the Department of Atmospheric and Oceanic Sciences, arrived at the air force base to take part in NOAA’s first flight into Hurricane Irene. The flight departed at 2:00 p.m. as Irene, then a Category 2 storm, began to develop an eye. By the end of the flight, the storm seemed to be starting an eyewall replacement cycle. As this process could eventually lead to an intensification of the storm, it was an important feature to keep an ‘eye’ on during the successive flights.
Early the next morning, Aug. 24, graduate student Matthew Sitkowski and research scientist Chris Rozoff, both from the NOAA Cooperative Institute for Meteorological Satellite Studies (CIMSS) arrived at the Aircraft Operations Center and took part in a pre-flight weather briefing. Takeoff was at 4 a.m. It took just over two hours to get to the southeastern Bahamas, where Irene continued to intensify. The flight-level data showed that the storm contained double wind maxima and an eyewall replacement cycle was underway. This proved to be good timing, because this physics and thermodynamics of the eyewall replacement cycle are research topics of Matthew and Chris.
During these flights, the three University of Wisconsin researchers monitored the onboard aircraft instrumentation. With each pass, the wind speed increased and the pressure dropped. It was clear that Irene was intensifying. The cloud-filled eye which Lisha saw during her passes had evolved into to a bright, sunlit eye by the time Chris and Matthew made their fourth pass. At this time Irene had developed into a massive storm. Those onboard knew this was not good news as Irene would soon take aim at the East Coast. 
The data collected on flights like these are used immediately in a number of computer models to help narrow predictions for both the track and intensity of the current storm. Outside of hurricane season, scientists work continually to refine and improve these models in order to improve our forecasting ability. Data collected during these flights will be used for years after the storm has passed in research done at institutions like the University of Wisconsin-Madison. Lisha Roubert’s current research, for example, uses data collected during flights through Hurricane Rita in 2005. Data from this hurricane will help validate model improvements, and suggest additional areas of research and development.
To improve hurricane forecasting, it is essential that data from every hurricane be collected. Models will only improve if the Hurricane Hunters continue their flights through these storms, and researchers gain access to that data.