Update: Tropical Cloud Systems and Processes (TCSP) Mission

From Scott Braun: Image removed.Vertical slice showing rain structure across hurricane Emily - 1:30 - 2:00 AM CST July 17, 2005

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From July 14-16, missions were flown both night and day in the Eastern Pacific to survey the large-scale flow and precipitation associated with two tropical disturbances that exhibited some potential for genesis into one or two tropical cyclones. On July 14th, a NOAA P-3 aircraft sampled the westernmost disturbance and found a broad low-level shear zone associated with the ITCZ. On July 15-16, a single NOAA P-3 generally flew during the day and a P-3 and the NASA ER-2 flew at night as a mid-level cyclonic circulation developed in the easternmost system. Much of the precipitation was stratiform in nature. By the end of the last flight on Saturday afternoon, the circulation appeared to be extending down to lowers levels. Unfortunately, three consecutive days of flights, a damaged windshield on one of the P-3’s, and the approach of Hurricane Emily, lead to the NOAA aircraft being unavailable for further flights into the Pacific disturbances. Over the next several days, the westernmost disturbance developed into Tropical Storm Eugene while the easternmost one dissipated. Consequently, the 3 days of flights sampled the very early stages of both a developing and non-developing system. The later stages of development will be studied using satellite remote sensing data, including Quikscat, Aqua, TRMM, and GOES. With the P-3's unavailable Saturday night, the ER-2 was sent to overfly Hurricane Emily, which was just shy of Category-5 intensity, as it passed south of Jamaica and was headed in a direction toward the Yucatan peninsula and eventually the Texas-Mexico border. The pilot made several crossings of the eye before deciding that the turbulence above the storm was too severe. The remainder of the flight involved flying box formations just outside the eyewall. Data collected by the ER-2 Doppler Radar during this flight showed a compact eye about 20 miles across with the most impressive evidence thus far of intense strong convection in the eyewall of a hurricane. This convection extended up to nearly 58,000 feet altitude. There have been theories that intense eyewall convection with extremely strong vertical air currents is important in intensifying a tropical storm. Intense convection in mature hurricanes is infrequent and its role on hurricane intensity is still uncertain. These observations are the first step in documenting this convection and understanding its role in the most powerful hurricanes. The Tropical Rain Measuring Mission (TRMM) satellite has documented similar cases of this intense convection, but this is the first time we have been able to obtain close-up measurements of such a storm. One of the P-3s returned to Florida on Sunday to have its windshield repaired. The second P-3 left Costa Rica to fly within Emily as it entered the Gulf of Mexico on Monday. It will return to Florida for a day and is then expected to be able to participate in potential flights beginning Thursday, July 21st, for up to three days.