The flight will leave MacDill AFB, FL at 8:00 AM EDT and recover at 6:00 PM EDT at MacDill AFB, FL. It is executing a Landfall experiment as Hurricane Isabel comes ashore.

The research flight plan was designed to accomplish two goals:

1. Collect data over the ocean in high wind regimes for the Ocean Winds project, and
2. Collect data during the landfall of the hurricane in support of HRD's Tropical Cyclone Windfields at Landfall.

An incredible array of portable wind towers and Doppler radars were deployed in eastern North Carolina: 4 towers from a combined Clemson University - University of Florida team were erected right at the coast (CUUF T0-T3), 3 Portable radars from the Center for Severe Weather Research (DOWs) were located with a Texas Tech WEMITE wind tower on a small spit of land in Pamlico Sound, TTU and University of Oklahoma teams set up SMART-R radars at two inland locations to examine mesoscale and convective scale features. TTU also deployed other towers in a grid to examine coherent structures in the boundary layer.

Mission Summary :

Four radar composites were transmitted which showed evidence of an inner eyewall trying to form before the storm made landfall. There were also about 32 dropsondes released during the flight.

NOAA 42 left Tampa at 1202 UTC, 18 September 2003, and reached our IP at ~1350 UTC, near buoy 41002. Figure 2 shows the flight track and figure 3 shows the GPS sonde splash locations. The aircraft descended to 7,000 ft and remained at that altitude until the over land portion of the flight. The eyewall was already on the coast (Figure 4a) so the eyewall pattern was truncated. We then flew several short legs in and out of the eyewall to collect IWRAP and sonde data in the higher winds. During this time the remnants of the inner eyewall seemed to develop a crescent shaped region of convection, as if the inner eyewall was reforming.

Numerous sondes were deployed in near Diamond Shoals which should be compared with the data collected at the T3 CUUF tower on Cape Hatteras. At 1710 we made a run up the coast to DUCN7 to investigate the transition in the windfield as the wind moved on shore. In hindsight we should have planned our track to be more parallel to the surface wind but these sonde data should still be valuable to describe the changes in this region, especially when combined with the T0 tower data.

After turning to head South after dropping a GPS sonde at buoy 44014, at 1758 we climbed to 12,000 ft to begin an over land pattern. By this time the center of the storm was about equidistant from the two SMART-R radars. We flew an upwind pattern starting at CLKN7 then passing over the two SMART-R radars, then back to the coast to tower T3. During that eastern leg we passed right through the inner convective feature (Figure 4b). The research portion of the flight finished by passing near the DOWs and other TTU tower. We left the storm at 1937 and landed at MacDill at 2150 UTC.

Evaluation :

This hybrid mission went well. Most of the sondes worked and the radar functioned well. We had some confusion in the second part of the flight while planning the overland portion, but once everyone got on the same page things went well. In future landfall flights we must make sure that everyone has a list and map of all the surface stations so that communications go smoothly between LPS, Flight Director and the Flight Crew.

Acknowledgments :

Paul Flaherty, Tom Shepherd John Adler, and the flight crew flew a complicated pattern with their usual dedication and attention to detail. Sean McMillan kept the radar running, while Mark Rogers and Bobby Peek managed to keep up with our evolving plans for AXBT and GPS sonde drops.

Problems :

When the Lower Fuselage radar is operated in sector mode, to avoid interference with the IWRAP, the LF display and data archival are degraded significantly. The IWRAP should be modified to avoid this problem, as the LF is an important instrument during landfall flights.

Peter Dodge
Lead Scientist

Mission Data :

Figures

Tables

• WL150 wind in lowest 150 m
• DLM: wind dir and speed, max min pr of layer
• MBL: Mean bdry layer wind dir, speed
• LST: Height of last wind
• RAINBAND, EYE, EYEWALL: environment (eyewall is followed by nav octant)