Doppler radar quick-looks from 4PM P-3 flight, 2 September 2010

As Earl continues to accelerate northward and weaken as it approached Cape Hatteras (depicted by the black line in the upper left of the images)  NOAA P-3 missions continue to collect airborne Doppler radar data to use in initializing and evaluating model guidance. Included here you will see images of the horizontal winds within the inner core of Hurricane Earl sampled from the tail Doppler radar on the P-3 late on 2 September 2010. These images are at three altitudes, 1km, 5km, and 10km, using a composite of winds from four legs oriented southwest-northeast, northwest-southeast, east-west, and south-north. Wind, temperature and relative humidity from GPS dropsondes dropped from the P-3 are also visible at 1 km altitude. Unlike the previous missions the strongest winds are located on the east side of the storm at 1 km altitude, rotating rapidly clockwise in azimuth with increasing altitude until it is southeast of the center at 10 km. This clockwise rotation of the wind maximum with increasing altitude is similar to that in the three previous missions analyses, suggesting that Earl is encountering vertical shear of the horizontal wind over the vortex from the increasing westerlies aloft impacting the storm as it moves further northward. The major difference between this analysis and the previous few is that the peak winds are much weaker suggesting Earl is weakening as the vertical wind shear over the center increases. Other changes evident are a much more asymmetric wind field with stronger winds on the east and southeast side of the storm and a pretty dramatic increase in the radius of the maximum wind over that in the past analyses. These changes suggest the storm is weakening rapidly and the wind field is more asymmetric projecting more of the structure on to wavenumber 1.