Microbursts and Null Events Near Cape Canaveral, FL
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Authors
White, Danielle
Date
2023-05
Type
Thesis
Language
en
Keywords
Alternative Title
Abstract
Abstract
MASTER OF SCIENCE IN APPLIED METEOROLOGY
By
Danielle White
Plymouth State University, May, 2023
Microbursts are thunderstorm downdrafts that produce localized damaging wind,
no larger than 4 km in diameter (Bringi et al. 1996). These storms, which typically contain
hail in the early stages of development may not produce rain and can occur in any
geographic region (Amiot et al. 2019). In Florida, wet microbursts commonly pose a major
risk to operations at Cape Canaveral Air Force Base. To improve forecasting microbursts,
six variables were derived from sounding data provided by the University of Wyoming,
valid no more than 4 hours before thunderstorm formation, and including CAPE, KI, TT,
∆𝜃! , mid-level relative humidity, and sub-cloud humidity. Peak wind speeds provided by
Kennedy Space Center were recorded where the reflectivity is at least 45 dBZ occurring
above the freezing level. Comparisons of null and microburst events with this data were
used in analysis to determine how well each of the six variables do in microburst detection.
The relative humidity variables proved to be the best indicators. Ideal humidity values may
vary based on location but should be low enough for hail to melt and evaporate to induce
negative buoyancy, but not so low that the thunderstorm begins to lose moisture and
structure. A similar explanation can be applied to the ∆𝜃! , which was also found to be
helpful in forecasting microbursts. New thresholds for each variable were determined to
maximize the performance of forecasting guidance.