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Mission Summary
Hurricane Floyd
Winds At Landfall

990916H Aircraft: N42RF

Scientific Crew
Chief ScientistsSam Houston
Peter Dodge
Cloud PhysicsMark Croxford
RadarPeter Dodge
WorkstationPaul Leighton
Air-Sea InteractionMark Croxford
ScatterometerJim Carswell

Aircraft Crew
CockpitCAPT Dave Tennesen
LCDR Brian Taggart,
LCDR Tim O'Mara
Flight EngineersGreg Bast
Rock Torrey
NavigatorLT Carl Newman
Flight DirectorStan Czyzyk
EngineersJim Roles
Sean McMillan
Juan Carlos Prada-Bergnes
Mark Rogers
ObserverVince Cappella (USA Today)

Mission Briefing: Initial planning for a Winds Near Landfall mission into Hurricane Floyd began when Florida's central east coast was considered a likely target for landfall. It later became evident that a large trough approaching from the west would likely cause Floyd to turn northward away from Florida. The Carolinas were threatened by Floyd nearly two weeks after Hurricane Dennis (Dennis turned out to sea after closely approaching the southeast coast; Dennis later made landfall in North Carolina as a tropical storm after it had meandered offshore for several days).

The advanced planning for the Floyd landfall mission was no less diff~cult than in previous cases. The fact that Dade County was in a hurricane warning and AOML was evacuated made this task even more diff~cult. Nearly all planing had to be done from NHC and Tampa. The NOAA P3's were put on alert for potential landfall missions to take place on the afternoon of 15 September or the morning of 16 September. It became evident on the morning of 15 September that Floyd would remain offshore until very early on 16 September. Therefore, N43RF was used in an Air-Sea experiment in Floyd offshore from South Carolina near the Gulf Stream. At the end of this experiment, some Winds Near Landfall segments were also flown along the North and South Carolina coastline. This mission complemented closely the tasks of our NOAA 42 flight as Floyd made landfall.

Ground-based teams from Texas Tech, NSSL, and the University of Oklahoma deployed three 10 m meteorological towers, three mo bile mesonets, and a single Doppler on Wheels (DOW) to study the wind field of Floyd as it made landfall (Table 1). The mobile mesonet teams were able to gather near surface measurements in Floyd's eye and eyewall. All of these field teams had been located in central Florida when that area was threatened the day before. They made an early exit northward, but ran into problems obtaining fuel for their vehicles, especially in Georgia, which was under a hurricane warning (a team from Clemson University, which was in south Florida, was unable to reach North Carolina in time to set up for Floyd's landfall).

Mission Synopsis: When it became evident the morning of 15 September that Floyd was accelerating northward and would likely make landfall in the Carolinas early on 16 September, the scheduled take off time for N42RF's mission was moved from 0400 UTC to 0300 UTC. Sam Houston and Mark Croxford drove to Tampa from the TPC to meet the other HRD crew members, Peter Dodge and Paul Leighton. The mission briefing took place at 0100 UTC 16 September at Tampa International airport where N42RF was located. At that time, the pilots expressed concern about operating over land where mesovortex signatures had earlier been reported north of Floyd. A tornado watch box extended along the coast from Charleston to Morehead City, and tornados had been reported on the Outer Banks that afternoon. Therefore, the over land portion of the flight plan was eliminated. The remaining portions of the landfall experiment were briefed, which included an initial "figure 4", a series of coastal patrols and a box pattern. The flight legs had radials in conjunction with the KLTX and KMHX WSR-88D's and the DOW. In addition, GPS dropwindsondes (hereafter referred to as sondes) were launched near university tower sites and NDBC platforms and AXBT deployments were made. The proposed flight track provided to the Flight Director, Stan Czyzyk, is shown in Fig. 1. The flight-level chosen was 8000 ft and the Air Force Reserves WC-130 operating in the area was flying at 10,000 ft.

We took off from Tampa International airport at 0316 UTC and arrived at our IP at 0433 UTC. Enroute, Frank Marks hailed us on the radio from N43RF and provided a useful summary of details about his mission, which had been quite successful. He indicated that Floyd's center was still offshore, so our proposed flight pattern appeared to be on target (see the actual flight track in Fig. 2). We made our first sonde drop near NDBC buoy 41004 at 0441 UTC, where winds were near 34 m s~l at the surface (see Table 2 for a list of sondes dropped). As we arrived from the south of Floyd, the radar reflectivities indicated an ill-defined and "ragged" south eyewall ( Fig.3) even though the infrared satellite image near landfall still looked impressive (Fig. 4). We passed through the flight-level circulation center at 0506 UTC (see Table 2 for center fixes) and could see more vigorous convection in the northern eyewall on radar. We proceeded northeast through this convection on a radial toward the KMRX radar site. In addition to the sonde drops between buoy 41004 and the turn near KMRX, we dropped 4 AXBT's with good data (see Table 4 for AXBT drop locations). After this, we turned to the left at the beach and flew a coastal patrol from near KMRX to Cape Fear. We dropped sondes at 4 locations in the onshore flow along this course, including near the DOW site at Topsail Beach. We made another pass through Floyd's center while it was still a few miles south of Cape Fear at 0556 UTC before circling in the eye and returning on a course that would take us into a coastal patrol from Cape Fear to Myrtle Beach, SC. Three good sondes were dropped in the offshore flow during this portion of the coastal patrol (these were offshore from the TTU tower near Holden Beach, Grand Strand General Airport, and the Myrtle Beach Jetport). By the time we had returned to Floyd's eye at 0630 UTC, it's circulation center was over Bald Head Island at Cape Fear, NC (this was landfall).

We then flew the beginning of the first box east of Floyd over the FPSN7 C-MAN site where we dropped a sonde and then east toward our next turning point near 33.5°N 76.5°W at 0700 UTC (see Fig. 2). We proceeded north from there toward the Cape Lookout (i.e., CLKN7) to drop a sonde at 0710 UTC. Unfortunately, all of the AXBT's we dropped along the east and northbound legs of the box failed. We flew toward the DOW location and dropped a sonde before passing through the eye, which was 3 miles inland from Wrightsville Beach, NC at 0728 UTC. We then returned to FPSN7 to start the new box (no sonde winds). Our next AXBT drop near our turning point 33.5°N 76.5°W failed again, but we had a good sonde drop here at 0751 UTC. Our next leg to CLKN7 was uneventful and we dropped a sonde here at 0808 UTC. As we approached the DOW site again, the eyewall appeared on radar as a southwest to northeast oriented feature with its cells appearing to be more convectively active than earlier. Prior to the fifth pass through Floyd's eye at 0823 UTC, we dropped two more sondes. The last box began after we left the eye and dropped our last sonde at FPSN7 and CLKN7 during this box. We also launched a successful AXBT during this box. We were also fortunate to have a good AXBT drop this time near our turning point. Our last portion of the box after CLKN7 involved two more sonde drops in the onshore peak winds region and two more south of the eye in the offshore winds region. We made two more penetrations into Floyd and then proceeded home via Buoy 41004. Our landing after a very successful mission was at MacDill AFB at 1136 UTC.


The mission was very successful and met nearly all of our objectives. We had good luck with Floyd's eye being located offshore for our first two penetrations. This gave us time to complete most of the legs of a mod)fied "figure 4" and a coastal patrol before the circulation center crossed the coastline. The real-time flight-level data adjusted to the surface plus the SFMR data from the previous mission by N43RF were used in the HRD surface wind analysis provided to the forecasters at NHC for 0700 UTC ( Fig. 5) The sondes dropped in the storm are plotted in Fig. 6 and listed in Table 3. The boundary layer measurements from the sondes appear to have been good in most cases, especially near the coast and C-MAN stations. It is believed that we will have an excellent data set for analysis using the flight-level winds from N42RF, the Air Force reconnaissance flight, and the sondes. The near surface and surface winds should also be available from sondes, the SFMR, and the scatterometer for documenting Floyd's winds in the offshore and onshore flow near the coast.


Paul Leighton was very helpful in assisting Peter Dodge with drawing up the flight plan to meet the FAA deadline. Mark Croxford provided excellent notes from the mission and was a valuable asset on board. Special thanks to Hugh Willoughby, Peter Black, and Steve Feuer for providing guidance on Floyd's whereabouts and projected track prior to our mission. The AOC crew also very helpful during our mission despite the late hours it required us to be flying and working. We especially appreciate the early start (shortly after 0300 UTC instead of 0400 UTC) take off that allowed us enough time to arrive on station for our missi on before Floyd moved inland. Sam Houston was contacted by Steve Delgreco of NCDC and Rainer Dombrowsky of the ASOS Program Office about turning on hi-res ASOS data for states which might be affected: Florida, Georgia, and South Carolina were requested (unfortunately North Carolina was later put under a warning and the hi-res data retrieval may not have happened at all such sites here). Reid Hawkins, SOO at the Wilmington NWSO provided hi-res ASOS data for ILM and CRE.


The radar system froze briefly a few times during the flight, but not in mission critical regions. Three of the AXBT's failed in the box pattern east of Floyd, but our last one provided good data. A few sonde failures occurred, but there did not seem to be an unusually large percentage of failures. No known problems with data gathered by existing or special platforms in North and South Carolina were reported at the time of this writing.

Sam Houston and Peter Dodge

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