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Over the past 20 years, improvements in hurricane computer modeling, observational instrumentation, and forecaster training have greatly increased forecast accuracy. The many complex interactions that occur within the atmosphere remain to be fully understood, especially at the small scales associated with tropical cyclones. However, these milestones mark critical advances in numerical weather prediction that are paving the way to the next generation of NOAA models. While hurricanes cannot be controlled, vulnerability to these complex storms can be reduced through preparedness. Early warning and improved accuracy of forecasts can help save lives and reduce property damages caused by hurricanes.

AOML is currently in the midst of a multi-year effort called the Intensity Forecasting Experiment (IFEX). IFEX aims to improve the understanding and prediction of intensity change by collecting observations from all stages of a tropical cyclone life cycle—genesis to decay—to enhance current observational models. By building on years of observational expertise and cutting-edge approaches to data integration and model development, hurricane scientists at AOML lead advancements in observations and modeling that have improved intensity forecasts by 20% in recent years.

NOAA Hurricane Hunters are flying back-to-back missions to study the newly developed Tropical Storm Hermine in the Gulf of Mexico, capturing its evolution from a cluster of thunderstorms into a tropical storm. Getting data during such transitions can help improve hurricane models which currently don’t predict transitions well. Our understanding of the physical processes of early storm development remains limited, largely because there are few observations. 

As a hurricane approaches landfall, citizens are hoping that they are adequately prepared for the potential damage from strong winds and rising oceans. NOAA’s job is to forecast the storm location and strength, or intensity, to help communities make the best informed decisions. For many scientists, predicting intensity is a challenge at the forefront of hurricane research, and in recent years advancements in observations and modeling have improved NOAA’s forecasts of intensity by 20%. We are now at the point where scientists can observe and predict with very fine detail what is happening in the inner core of the storm.

Early on the morning of August 29th, 2005, Hurricane Katrina made landfall on the Louisiana delta region and the Mississippi coast.  The storm surge brought enormous damage to the Gulf Coast and, when the levees around New Orleans failed, a great number of fatalities.  Coming amidst the very busy 2005 hurricane season, Katrina brought death and destruction not seen in a U.S. land-falling hurricane in decades.

AOML’s hurricane researchers conducted a number of field activities in August that provided data and critical insights into two Atlantic tropical cyclones, Danny and Erika. The two storms enabled researchers to test new instruments in support of the 2015 Hurricane Field Program and conduct research that will benefit future forecasts. Among the highlights were more than 15 successful manned and unmanned aircraft missions into Danny and Erika to collect and provide real-time data to the National Hurricane Center (NHC), as well as evaluate forecast models.

A geo-referenced radar image taken during Hurricane Danny with the P-3’s lower-fuselage radar on Friday, August 21, 2015. Image credit: NOAA

NOAA flew five P-3 aircraft missions and two G-IV jet missions into Hurricane Danny, the first major hurricane of the 2015 season. For Tropical Storm Erika, NOAA flew five P-3 missions and three G-IV missions as the storm impacted the Caribbean. The P-3 missions into Danny marked the first real-time transmission of geo-referenced imagery from the P-3’s lower-fuselage radar to NHC forecasters. This imagery provided valuable information about the structure of Danny as the storm churned in the Atlantic far from land.

The P-3 flights also measured the wind structure of Danny and Erika and the wind shear environment surrounding them. Using the Tail Doppler Radar aboard the P-3, researchers documented high levels of wind shear across the Caribbean, the product of a strong El Nino and a major factor contributing to the dissipation of both storms.

During missions into Danny and Erika, scientists gathered observations for the first time with a Doppler wind lidar instrument mounted on the side of the P-3 fuselage that measures wind velocity in regions without rain. The lidar data will be processed and evaluated for possible inclusion in the HWRF research model to improve wind speed estimates in model guidance.

NOAA’s P-3 aircraft flew multiple missions into Hurricane Danny & Tropical Storm Erika. Image credit: NOAA

NASA’s Global Hawk unmanned aircraft completed the first two flights of its 2015 NOAA campaign when it flew above Tropical Storm Erika on August 26th and 29th. The Global Hawk used onboard instruments to profile the inner workings of Erika and released dropsondes to collect temperature, moisture, wind speed, and wind direction data. The real-time data were transmitted for the first time and incorporated into operational forecast models.

Other instruments aboard the Global Hawk, such as the microwave sounder from NASA’s Jet Propulsion Laboratory, gathered vertical profiles of temperature and humidity and was able to provide a unique view of Erika’s interaction with the Saharan Air Layer, a mass of dry air that inhibited Erika’s growth.

The Global Hawk, managed by NASA’s Armstrong Flight Research Center in California, provided a unique vantage point of Erika at 60,000 feet altitude, flying about 15,000 feet higher than NOAA’s G-IV jet. Both of its flights were 24 hours in length, nearly three times as long as that of the manned aircraft. The Global Hawk is part of NOAA’s Sensing Hazards with Operational Unmanned Technology (SHOUT) project, which seeks to improve hurricane forecasts of track and intensity using data collected by the unmanned aircraft from high in the stratosphere down to the ocean’s surface.

Below the ocean’s surface, another type of unmanned vehicle was in place, collecting data on Erika’s interaction with the upper level of the ocean as the storm passed through the Caribbean. AOML’s two underwater gliders traversed the waters off Puerto Rico, gathering temperature measurements that are critical to understanding the ocean’s role in how storms form, evolve, and change in intensity. These data should also provide researchers with a better understanding of the ocean’s response to the passage of storms which, in turn, will improve ocean models used in hurricane forecasts.

Data collected by NOAA’s hurricane hunter aircraft and the Global Hawk were uploaded in real-time to the Global Telecommunications System for inclusion in environmental models, better enabling researchers to predict the future activity and intensity of Danny and Erika.