Non-Convective Wind Climatology and Synoptic Overview
for Selected Cities in the Mid Mississippi Valley (14)
Alyssa Otten, Saint
Louis University, St. Louis, MO
Fred Glass, NOAA
Mark Britt, NOAA
Charles Graves, Saint
Louis University
Abstract:
The accurate forecasting of
strong non-convective wind is essential, as these events are often responsible
for significant damage to property. This study seeks to meet operational
forecasters' need to better understand the nature of non-convective winds in
NWS St. Louis's County Warning Area(CWA) by gaining a pattern recognition of event
signatures to aid in forecasting future events. In order to accomplish this, a
non-convective wind climatology was built with observational wind data from
five cities in the Mid Mississippi Valley. Additionally, synoptic composites of
non-convective wind events were prepared for various meteorological fields.
Non-convective wind
observations from 1973-2016 were analyzed for five cities within the Mid
Mississippi Valley Region. Three cities in Missouri: St. Louis, Cape Girardeau,
and Columbia. Two cities in Illinois: Quincy, and Mt. Vernon. Observations
meeting NWS Advisory and Warning criteria were identified, and a climatological
analysis was performed to look at distribution of observations by month, wind
direction, and time of day. The data was then parsed to determine the number of
advisory/warning hours observed for each event this distribution was visualized
in a box and whisker format. Synoptic composites were also generated for each
city using the six-hour North American Regional Reanalysis(NARR) dataset. Seven
synoptic fields were deemed useful in developing an understanding of
non-convective wind patterns: 500mb and 700mb heights and vorticity, 850mb and
925mb geopotential heights, temperature advection, and temperature, Mean Sea
Level Pressure, Mid-level and low-level lapse rates.
After analysis, distinct
patterns were found for monthly, directional, diurnal, and event day data. From
synoptic composites, trough placement and amplitude over the Mid Mississippi
Valley were consistent for all cities in the CWA. An increased area of cold air
advection was also consistent throughout all cities in the database.