Although it did not make landfall in Florida, Ivan's radius of maximum wind
spread well inside Florida's borders.
We tested the hypothesis that inner-core (0-100 km from TC center) lightning bursts produce different signs of TC intensity change based on 1) the intensity change 24 h prior to the burst, 2) the azimuthal location relative to the deep-layer (850-200 hPa) vertical wind shear, and 3) the radial location relative to the radius of maximum wind
The assimilation of observed surface wind data during an eyewall replacement cycle just before Hurricane Maria's Puerto Rico landfall allowed our model to capture the anomalous and rapid increase in the radius of maximum wind
. Hurricane Harvey's rapid intensification before landfall in Texas also provided an opportunity to explore the model's ability to represent the impact of intensity forecast uncertainties on the full wind field.
Structural metrics evaluated include the 2-km radius of maximum wind
(RM W), slope of the RM W, depth of the TC vortex, and horizontal vortex decay rate (a measure of TC size).
The database of synthetic events was made up of 2-hourly information for date (year, month, day, and hour), position (latitude, longitude), maximum wind speed, radius of maximum wind
speed, atmospheric pressure in the hurricane eye, and neutral atmospheric pressure.
These high echo tops, indicative of deep convection, were located at and inside the radius of maximum wind
speed (RMW) at 2-km altitude, a location often associated with intensifying TCs (e.g., Rogers et al.
These include the maximum sustained wind (MSW), defined as the maximum 1-min-average wind speed at the altitude of 10 m; the radius of maximum wind
(RMW); and the maximum radial extent of significant wind speed thresholds.
The secondary eyewall formation led to a larger radius of maximum winds
that was more favorable for withstanding the detrimental effects of strong vertical wind shear over the two-day period encompassing these events.
Matthew's radius of maximum winds
is only about 10 miles, which makes it an extremely tight storm and the impact it will have will depend on how close it comes to the coast.
Hurricanes lay down their windfield based on very specific parameters, including, for example, the central pressure and the radius of maximum winds
. "We always calibrate modeled physics to what has been observed historically," Dailey said.
Similarly for hurricanes, data on central barometric pressure, radius of maximum winds
, track angle at landfall and forward speed must be collected and analyzed.
In addition to its small radius of maximum winds
, the impact of the storm was tempered by the Sierra Madre Occidental Mountains, which shielded the more densely populated coastal exposures from widespread destruction that could have otherwise resulted from a strong Category 5 hurricane.