PONTE VEDRA BEACH, Fla – Dr. William Gray is famous for the seasonal hurricane predictions he started in 1984 but his legacy extends much earlier as a pioneer in understanding tropical weather.
Several friends honored his 2016 passing through an afternoon symposium highlighting his accomplishments at the 33rd Annual AMS Hurricane Conference.
His wisdom was equaled by a tremendous sense of humor which I fortunately experienced at several weather conferences.
He often said “It’s time to get down and dirty with the data.” This was his forte of looking at all factors in various ways.
Little was known about hurricanes in the 1960s when Dr. Gray published groundbreaking work about updraft behavior in storms. His 1970 paper showed how upward motions increased moisture while drying occurred in sinking processes.
Every meteorology student will understand this concept which Gray famously coined as “Up moist down dry.”
Gray’s research preceded satellite images which just begun showing the structure of hurricanes in the early 1960. Meteorologists didn't’t have forecast models to predict their motion. Yet he discovered how winds at specific levels of the atmosphere are responsible for steering.
Data was hard to find in those days but key to unlocking hurricane mechanics. Dr. Gray traveled to remote islands around the world to collect weather balloon data.
This helped paint a 3D picture of hurricane structure and identified tornado hot spot locations as typically occurring in their right front quadrant.
To this day we see a daily thunderstorm pattern in hurricanes where thunderstorms flair late at night into the morning, and fizzle by afternoon. This he explained, in 1977, was a classic process where low level convergence at night shifts upward into mid levels during the day.
Decades of observations lead to statistical correlations where he pioneered seasonal hurricane forecast activity.
One hallmark being the trend of low hurricane activity in the North Atlantic basin during El Niño years.