Mission Plan :

This mission was planned to be one of several back-to-back missions into Richard to study air-sea interaction and, possibly, rapid intensification. The G-IV had flown a pattern around Richard and in the western Caribbean and Se Gulf of Mexico earlier in the day. A 6-radial leg butterfly pattern with 100 nmi leg lengths was planned. Also, an extended leg, coming on from the west was planned to drop AXBTS and sondes along the forecast track of Richard. (Fig. 1). We would fly at 12,00 feet for most of the pattern. N43 would descend to 5,00-0 ft for our last SE-NW pass through the center, deploying a sequence of 12 AXBT/Dropsondes combos as a boundary layer flux module.

Fig. 1: Planned flight track into Richard. Combination AXBT/Dropsonde locations are indicated by circles.

Fig. 2: IR satellite imagery of TS Richard at 0215 UTC, 23 October 2010.

Richard was a minimum (35 kt) tropical storm (TS) prior to takeoff. It was located about 150 miles from the SW tip of Honduras. Prior to takeoff, the IR imagery look impressive, with active deep convection and not much apparent shear (Fig. 2). Microwave imagery (Fig. 3) suggested that the center of Richard was far enough off the Central America coast for N43 to operate in. Richard was forecast to slowly intensify and to track to the WNW just north of Honduras before making landfall in Belize or the Yucatan in a few days.

Fig. 3: SSMI microwave satellite imagery of TS Richard at 2215 UTC 22 October.

Mission Summary :

Fig. 4: Actual flight track into Richard.

Takeoff from San Jose was at 0205 UTC from MacDill and NOAA43 headed sooth for the Initial Point (IP) . about 240 nmi WNW of the projected center of Richard. N43 then headed east toward the center, releasing 4 AXBTs and dropsondes before reaching the IP of the butterfly patter, 100 nmi west of Richard's center at 0513 UTC. Tracking to the east, the winds suggested that the center was further west than anticipated but flight-level winds never indicated a well-defined center. After passing to the east side of Richard, we encountered vigorous convection with active lightning and the aircraft experienced large amounts of graupel. At 0550 UTC, we decided to descend to 11,000 feet to reduce the chances of flying through graupel again. We reached our East and NE points at 0554 and 0613 UTC, respectively and headed to the SW to try and find the flight-level center. As we approached the anticipated center, the winds were indicating that a possible center was to our south, very near the NE tip of Honduras, in an area where we did not have clearance to fly. At that point, we knew we had to abandon our planned butterfly pattern an we turned around to the NW, then SE to try again to find a wind center. We did not. Finally, we descended to 5,000 ft in the hope that a low-level center might be more well defined there and, if we could locate a center, to try the AXBT/Sonde sequence from near the RMW to the center. From a point about 60 miles east of the center, we attempted to track toward the center but realized that it was to close to the coast to fly and a very vigorous MCS was just outside of our no-fly zone and we could not maneuver safely around it. We turned around to the east, away form the MCs and made a final run from the SE to the NW, releasing our final AXBT/Sonde combos along the way. Figure 4 shows the actual flight track the N43 completed.

Fig. 5: Doppler wind analysis with dropsonde observation at 3.5 km for the west to East .

A real-time Doppler wind-analyses showed that Richard had a well-defined mid-upper level center (Fig. 5). This was in good agreement with the IR satellite image of Richard (Fig 6) that showed the main areas of convection still offshore. We headed back around the western tip of Cuba and landed back at Macdill at 1010 UTC.

Fig. 6: IR satellite imagery of TS Richard at 0745 UTC, 23 October 2010.

Problems :

Equipment and Expendables: A total of 18 AXBTs were deployed and all worked well. Of the 19 GPS sondes that were released, one failed. Three Doppler wind analyses were performed. The radar and flight-level systems performed well with only the radar system freezing up for very brief periods 3 times.

Michael Black
10/27/10

Page last updated June 21, 2011
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