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
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.