The Short and Long-term Variability of F2 or Stronger (Significant) Tornadoes in the Central Plains

An analysis of the interannual and interdecadal variability of significant tornado events that occurred over a four state region in the central plains was performed over a 53 year period (1950 - 2002) using the Storm Prediction Center (SPC) archives and simple statistical techniques. A synoptic composite analysis using the National Centers for Environmental Prediction (NCEP) - National Center for Atmospheric Research (NCAR) re-analyses was performed in order to determine whether there was support for the statistical relationships through the large-scale composite dynamics. The results showed that when the 53 year raw annual tornado occurrences are used, there was no statistically significant El Nino-related variability, and El Nino years produced slightly more tornado occurrences. However, when annual tornado occurrences were examined across different phases of the Pacific Decadal Oscillation, there was a likely tendency for more tornado occurrences in El Nino years during PDO2 and no significant interannual variability during PDO1 years. During the 1950 - 1976 period, other studies have found that significant tornado occurrences were overestimated. When a simple correction factor was applied here and the interannual variability re-examined, the strength of the statistical relationships changed such that there was now a likely tendency for fewer tornado occurrences in El Nino years during the PDO1 period, and no statistically significant relationship for PDO2 years. Finally an examination of the composite dynamics during the bulk of tornado season revealed that, out of five years examined, the large-scale flows were of similar dynamic character for four of them. The season which produced the most tornadoes qualitatively was shown to be slightly more conducive to severe weather production when using simple empirical severe weather indexes

Calibrating Human Attention as Indicator: Monitoring #drought in the Twittersphere

State climatologists and other expert drought observers have speculated about the value of monitoring Twitter for #drought and related hashtags. This study statistically examines the relationships between the rate of tweeting using #drought and related hashtags, within states, accounting for drought status and news coverage of drought. We collected and geolocated tweets, 2017–18, and used regression analysis and a diversity statistic to explain expected and identify unexpected volumes of tweets. This provides a quantifiable means to detect state-weeks with a volume of tweets that exceeds the upper limit of the prediction interval. To filter out instances where a high volume of tweets is related to the activities of one person or very few people, a diversity statistic was used to eliminate anomalous state-weeks where the diversity statistic did not exceed the 75th percentile of the range for that state’s diversity statistic. Anomalous stateweeks in a few cases preceded the onset of drought but more often coincided with or lagged increases in drought. Tweets are both a means of sharing original experience and a means of discussing news and other recent events, and anomalous weeks occurred throughout the course of a drought, not just at the beginning. A sum-to-zero contrast coefficient for each state revealed a difference in the propensity of different states to tweet about drought, apparently reflecting recent and long-term experience in those states, and suggesting locales that would be most predisposed to drought policy innovation

3D printed ventricular septal defect patch: a primer for the 2015 Radiological Society of North America (RSNA) hands-on course in 3D printing.

Hand-held three dimensional models of the human anatomy and pathology, tailored-made protheses, and custom-designed implants can be derived from imaging modalities, most commonly Computed Tomography (CT). However, standard DICOM format images cannot be 3D printed; instead, additional image post-processing is required to transform the anatomy of interest into Standard Tessellation Language (STL) format is needed. This conversion, and the subsequent 3D printing of the STL file, requires a series of steps. Initial post-processing involves the segmentation-demarcation of the desired for 3D printing parts and creating of an initial STL file. Then, Computer Aided Design (CAD) software is used, particularly for wrapping, smoothing and trimming. Devices and implants that can also be 3D printed, can be designed using this software environment. The purpose of this article is to provide a tutorial on 3D Printing with the test case of complex congenital heart disease (CHD). While the infant was born with double outlet right ventricle (DORV), this hands-on guide to be featured at the 2015 annual meeting of the Radiological Society of North America Hands-on Course in 3D Printing focused on the additional finding of a ventricular septal defect (VSD). The process of segmenting the heart chambers and the great vessels will be followed by optimization of the model using CAD software. A virtual patch that accurately matches the patient's VSD will be designed and both models will be prepared for 3D printing

Interannual Variability of Snowfall Events Southwest Missouri and Snowfall to- Liquid Water Equivalents at the Springfield WFO

In order to address the difficult issue of forecasting snowfall amounts for the general public, forecasters must be intimately familiar with the climatological behavior of snowfall events, and associated snowfall-to-liquid precipitation (SL) ratios that accompany events impacting the region. In Southwest Missouri, an average of 4 to 5 snowfall events of 3 inches or more occurred every year within the period of 1949 to 2002. These events were associated with an average SL ratio of about 12 inches of snow to one inch of rain (12:1). Past studies have also demonstrated relationships between the synoptic environment and SL ratios for a particular locale. Indeed, while many atmospheric and environmental factors contribute to the observed SL ratios in a particular event, quite often, recurring synoptic patterns are typically associated with similar SL ratios in Southwest Missouri. This study identified four synoptic patterns that bring heavy snowfalls to Southwest Missouri and these are associated predominantly with certain SL ratios. In Southwest Missouri, synoptic disturbances classified as southwest lows or deepening lows, processed large amounts of moisture and produced heavy snow. Sixty-seven percent of these events produced SL ratios of 12:1 or less, and 90% produced SL ratios of 14:1 or less. Snowfall events (progressive troughs and northwest lows) which brought less snowfall were typically associated with higher SL ratios. There was no significant El Nino-Southern Oscillation (ENSO) related difference in the number of snowfalls per winter season. When the study period was stratified to include interdecadal variability, changes in ENSO- related variability did emerge. Additionally, the SL ratios were smaller during El Niño years and there has been no trend in this tendency

The Columbia, Missouri, Heat Island Experiment (COHIX) and the Influence of a Small City on the Local Climatology

The heat island effect is a well known feature in the microclimate of urban areas but only a few studies have addressed the effect for smaller urban areas. We examine here the impact of Columbia, Missouri and the University of Missouri campus on the microclimate (temperature and precipitation) of central Missouri. We purchased twenty Radio Shack® digital Max/Min thermometers and ten standard raised-edge rain gauges and these were given to students, staff, and faculty participants who were chosen for their reliability to provide daily data over the course of a year, site the instrument, and their location (in order to provide reasonable coverage locally). We also included information provided by automated and cooperative weather stations, and the weather station at the regional airport located 11 km (7 miles) southeast of Columbia. Our results indicate that the city has no discernable impact on the distribution of monthly precipitation totals. We found a distinct urban influence on the local surface temperatures, and the inner city region and the urbanized area of south Columbia were approximately 2 - 3 oF (1.0 - 1.5 oC) warmer in the mean than the surrounding environment. This difference grows to 3 - 6 oF (1.5 - 3.5 oC) when comparing the mean of the warmest station in the city to that of coolest station outside Columbia. We also observed a seasonal influence, as the heat island effect was more evident in the mean monthly maximum (minimum) temperatures during the warmest (coldest) months

Interannual and interdecadal variability in the predominant Pacific region SST anomaly patterns and their impact on climate in the mid-Mississippi valley region

Previous research has demonstrated that Pacific Region SSTs and SST anomalies can be separated into seven general synoptic classifications (“clusters”) (A-G). Clusters B and G (C, D, and F) [A and E] were shown to be generally representative of La Niña (El Niño) [neutral] type SST distributions. Further, an analysis of the SST patterns from 1955 - 1993 demonstrated that clusters A - D were prominent from 1955-1977, while types E and F dominated the later period. Type G clusters were comparatively rare, but occurred during both periods. In retrospect, this shift during 1977 corresponds roughly with a change in phase of the Pacific Decadal Oscillation (PDO). After updating the analysis to include the 1994 to 2005 period, there was a corresponding change in the predominant SSTs associated with a change in phase of the PDO during 1999 and 2000. The results show that SST patterns did evolve from predominantly E and F-type anomalies in 1994 to A, B, D, and G-type anomalies through 2005. Thus, these results suggest that A through D-type (C, E, and F-type) SST clusters are characteristic of the negative (positive) phase of the PDO. Also, using a modified technique for generating phase diagrams, it is shown that there are interannual and interdecadal variations in the mid-Mississippi region monthly mean surface temperature and precipitation records that can be associated with the ENSO and PDO. Additionally, an analysis was performed to see if there was any statistical association between temperature and precipitation anomalies in the mid-Mississippi region and prolonged SST regimes. B, D and G anomalies were associated with warmer-than-normal conditions, while C and E type anomalies tended to be associated with cooler-than-normal conditions across the region. C, D, F, and G anomalies were associated with drier than normal conditions

Regional Climate Trends and Scenarios for the U.S. National Climate Assessment Part 4. Climate of the U.S. Great Plains

This document is one of series of regional climate descriptions designed to provide input that can be used in the development of the National Climate Assessment (NCA). As part of a sustained assessment approach, it is intended that these documents will be updated as new and well-vetted model results are available and as new climate scenario needs become clear. It is also hoped that these documents (and associated data and resources) are of direct benefit to decision makers and communities seeking to use this information in developing adaptation plans. There are nine reports in this series, one each for eight regions defined by the NCA, and one for the contiguous U.S. The eight NCA regions are the Northeast, Southeast, Midwest, Great Plains, Northwest, Southwest, Alaska, and Hawai‘i/Pacific Islands. These documents include a description of the observed historical climate conditions for each region and a set of climate scenarios as plausible futures – these components are described in more detail below. While the datasets and simulations in these regional climate documents are not, by themselves, new, (they have been previously published in various sources), these documents represent a more complete and targeted synthesis of historical and plausible future climate conditions around the specific regions of the NCA. There are two components of these descriptions. One component is a description of the historical climate conditions in the region. The other component is a description of the climate conditions associated with two future pathways of greenhouse gas emissions

From Too Much to Too Little: How the central U.S. drought of 2012 evolved out of one of the most devastating floods on record in 2011

Table of Contents Section 1: Introduction....................................................................... 1 Section 2: Regional Drought Perspective................................. 2 Section 3: State Drought Perspectives........................................ 3 Section 3.1: Colorado........................................................................... 20 Section 3.2: Illinois.................................................................. 25 Section 3.3: Indiana................................................. 29 Section 3.4: Iowa...................... 36 Section 3.5: Kansas............................................................... 42 Section 3.6: Kentucky............................................................................ 46 Section 3.7: Michigan.............................. 52 Section 3.8: Minnesota............................................................ 58 Section 3.9: Missouri..................................................... 63 Section 3.10: Nebraska................................................. 67 Section 3.11: North Dakota............................................ 73 Section 3.12: Ohio................................................... 79 Section 3.13: South Dakota..................................... 85 Section 3.14: Wyoming........................................... 96 Section 4: Conclusions.............................................................. 9

The Presentation of Temperature Information in Television Broadcasts: What is Normal?

In a typical weather broadcast, observed daily temperature information such as maximum and minimum temperatures are shown and compared to the daily average or “normal”. Such information, however, does not accurately describe whether or not that particular day is fairly typical for that time of year or truly an unusual occurrence. Thus it is suggested that the presentation of temperature information can be augmented with elementary statistical information in order to give a more meaningful presentation of temperature information without the need to explain the basis of such statistical information. A study of the climatological maximum and minimum temperatures over a 30-year period for Columbia, Missouri is performed in order to provide the rationale for displaying a "typical" temperature range. This information was incorporated into television weather broadcasts at KOMU TV-8, which is the campus television station and local NBC affiliate