The 2017 NOAA Intensity Forecasting Experiment (IFEX)

The Intensity Forecasting Experiment (IFEX) is a multiyear field campaign conducted by NOAA’s Hurricane Research Division, part of the Atlantic Oceanographic and Meteorological Laboratory (AOML), with the aim of improving prediction of hurricane intensity. The goals of IFEX focus on using observations to improve numerical forecasts, developing and refining measurement technologies, and improving understanding of the physical processes involved in intensity change. This talk summarizes IFEX field activities during the 2017 Atlantic hurricane season. As of early October, a total of 6 hurricanes were sampled, 4 of which (Harvey, Irma, Maria and Nate) had significant U.S. impacts.

A primary objective of the 2017 IFEX field campaign was to carry out the newly-designed Analysis of Intensification Processes Experiment (AIPEX) targeting tropical depressions and storms with the potential for intensification, especially systems with the potential for rapid intensification (RI) in moderate vertical wind shear environments. Three storms (Franklin, Harvey and Nate) were sampled near the onset of RI, the former two in coordination with the high-altitude Global Hawk UAS. Various stages of eyewall replacement cycles were also sampled in two of the major hurricane cases (Harvey and Irma). As part of the field efforts during the 2017 season, developing measurement technologies were highlighted, including: NOAA/AOML hurricane underwater gliders, Coyote small UAS (Maria), Doppler Wind Lidar (Maria and Nate), and dual downward-pointing SFMR (Nate). In addition, a new tail-Doppler radar system was employed with 3 times the along-flight-track resolution as in prior seasons. In all cases, standard reconnaissance data (including winds from the WP-3D tail-Doppler radar) were transmitted in real time to NOAA’s Environmental Modeling Center for assimilation into the operational Hurricane Weather Research and Forecasting Model.