TABLE 1. Estimated minimum SLPs and the observations upon which they are based for each time that N43RF flew into the eye of Hurricane Gilbert on 13 September 1988. Flignt-level observations are: UTC, time of observation; z, geopotential altitude in m; T and T_d, Celsius temperature and dewpoint; and P. corrected pressure in hPa. SLPs are estimated as follows: P_j, by statistical extrapolation (Jordan 1958b); P_j, by assuming virtual temperature constant at the flight level value between flight level and sea level; P _is, by assuming linear variation of virtual temperature between flight level and saturation at sea level temperature T_s; and P_it, by assuming a saturated adiabat from 27°C at sea level to P_t and interpolating linearly from P_t to flight level.