NOAA completes missions into Major Hurricanes Franklin and Idalia – Hurricane Research Division

NOAA conducted 12 P-3 and 5 G-IV operational and research missions into Hurricanes Franklin and Idalia between 21 and 31 August. The NOAA P-3 conducted operational missions to “fix” (observe the location and intensity of) both systems and also Tail Doppler Radar missions to gather data to improve model initial conditions and forecasts. The NOAA G-IV conducted one Tail Doppler Radar mission and numerous Synoptic Surveillance missions with the goal of improving forecasts.

NOAA scientists, in collaboration with scientists from the Office of Naval Research, were also able to conduct important research into the hurricanes with the aircraft. The aircraft captured the organization and development of both systems before and during the periods they underwent rapid intensification.

They conducted the Vortex Alignment Module that is designed to investigate how intensity is related to the vertical alignment of a storm’s circulation. As tropical cyclones develop, the rate at which they intensify is strongly related to the vertical alignment of its circulation. However, the physical processes responsible for changes in the alignment of the circulation are not well understood. This module aims to improve our understanding of the alignment process through the collection of high-frequency observations of tropical cyclone.

They deployed University of Miami Airborne EXpendable BathyThermographs (AXBTs) to measure ocean surface and sub-surface temperature near the hurricanes and successfully the data to ground servers at the NOAA Aircraft Operations Center.

1. They conducted the Flight-Level Assessment of Intensification in Moderate Shear module to repeatedly sample the region of maximum wind speed of weak, but intensifying systems, in order to assess how both the wind and precipitation changes during intensification.  Weak systems in moderate shear are often asymmetric, and substantial intensification can occur on short time scales (1-2 hours or less).  By focusing on the part of the storm where the strong winds and rain exist, we can to capture changes to understanding how intensification begins.

1. AOML/HRD also collaborated with scientists at the University of Washington to deploy microSWIFT ocean wave buoys from a NOAA P-3 ahead of Idalia’s forecasted storm track.

1. They performed the Surface Wind and Wave Module overflying splash locations of dropsondes to collect data in mature hurricanes to continue improving surface wind speed and rain rate estimates from the Stepped-Frequency Microwave Radiometer (SFMR) and understand how the wind speed observations from the SFMR, flight level, dropsondes, and tail-Doppler radar (TDR) should be averaged and adjusted to estimate hurricane intensity. These can provide more accurate observations to estimate intensity and size along with improved estimates of marine hazards and comparisons with satellite observations, allowing for better watches and warnings for a potential impacts to be provided to emergency managers and the general public.

The aircraft also flew the Stratoform Spiral Module where the P-3 spiraled up to 20,000 ft altitude in precipitation to obtain measurements of ice particles vital in evaluating and improving the representation of clouds, water droplets, ice, and aerosols in computer models. Such an improvement is important in making better rainfall and potentially better hurricane intensity forecasts.

For more information, contact aoml.communications@noaa.gov.