What Was More Important in the Rapid Intensification of Earl (2010): Intense Convection, Widespread Rainfall, Environmental Conditions, or None of the Above?

Between 0600 UTC 29 August 2010 and 1800 UTC 30 August 2010, Hurricane Earl rapidly intensified from a 55-knot tropical storm to a 115-knot hurricane. Earl was one of the best-observed cases of rapid intensification (RI, Kaplan and DeMaria, 2003) ever, with five flights of the NOAA P-3 and two flights of the NASA DC-8. This study focuses on the hours leading up to RI (from 0000 UTC August 28 to 0600 UTC August 29) as well as the RI period. We make use of the data from the tail Doppler radar of the NOAA P-3 and the APR-2 Doppler radar on the NASA DC-8 for quantitative vertical velocity estimates and horizontal and vertical reflectivity profiles. We will also use passive microwave observations to subjectively assess the precipitation structure of Earl and to quantitatively estimate the convective intensity and precipitation coverage within Earl's core. We are particularly interested in determining the relationship of intense convection vs. widespread moderate rainfall to the intensification. Preliminary indications are that intense convective episodes occurred before and during Earl's RI, but it is not yet clear whether these convective events are well-connected with periods of wind-strengthening in the inner core.