The summer of 2022 was very dry across Missouri and the surrounding regions including much of the Great Lakes, Midwest, and southern plains of the USA. A comparison of this summer to the dry summer of 2012 and the relatively wet summers of 2018 and 2021 was carried out using the National Centers for Environmental Prediction/National Centers for Atmospheric Research reanalysis, the Climate Prediction Center teleconnection indexes, and the blocking archive at the University of Missouri. The summer of 2022 was like that of 2012 which was characterized by a strong 500 hPa height anomaly centered over the western US and plains as well as very little blocking in the East Pacific. The summers of 2018 and 2021 were characterized by more zonal flow over the USA and more blocking in the East Pacific, similarly to the results of an earlier study. The teleconnection indexes for the prior spring and summer were largely similar for the two drier years and opposite for the wetter years. The surface conditions for the drier years were more similar while these were opposite for the wetter years. The integrated enstrophy (IE) used in earlier studies identified a change in the large-scale flow regime in early June 2022, which coincided with a decrease in the precipitation over the study region. However, one key difference was that the spring of 2022 was characterized by blocking more consistent with a wetter summer. This would have made the predictability of the drought of summer 2022 less certain.

Drought-related decision-making and policy should go beyond numeric hydrometeorological data to incorporate information on how drought affects people, livelihoods, and ecosystems. The effects of drought are nested within environmental and human systems, and relevant data may not exist in readily accessible form. For example, drought may reduce forage growth, compounded by both late-season freezes and management decisions. An effort to gather crowdsourced drought observations in Missouri in 2018 yielded a much higher number of observations than did previous related efforts. Here we examine 1) the interests, circumstances, history, and recruitment messaging that coincided to produce a high number of reports in a short time; 2) whether and how information from volunteer observers was useful to state decision-makers and to U.S. Drought Monitor (USDM) authors; and 3) potential for complementary use of stakeholder and citizen science reports in assessing trustworthiness of volunteer-provided information. State officials and the Cattlemen's Association made requests for reports, clearly linked to improving the accuracy of the USDM and the related financial benefit. Well-timed requests provided a focus for people's energy and a reason to invest their time. State officials made use of the dense spatial coverage that observers provided. USDM authors were very cautious about a surge of reports coinciding closely with financial incentives linked to the Livestock Forage Disaster program. An after-the-fact comparison between stakeholder reports and parallel citizen science reports suggests that the two could be complementary, with potential for developing protocols to facilitate real-time use.

During the latter part of the 20th century and into the 21st century, research has focused on evaluating how to more effectively utilize upper‐air soundings and satellite analysis of atmospheric water vapour transport pathways typically referred to as “atmospheric rivers” (ARs) in order to better forecast heavy rainfall events. Rainfall associated with ARs may include a significant portion of monthly and seasonal rainfall when they occur within the North‐Central Mississippi Valley Region. A comprehensive analysis of surface and upper‐air maps and upper‐air soundings and the associated vertical wind profiles is conducted to help build a relationship between the intensity and duration of heavy rainfall events during the period 2000–2015. The goal is to develop a proxy by which rainfall events can be predicted more accurately and work towards developing improved operational forecast protocols. In addition, a secondary goal is to evaluate possible connections between AR dynamics as highlighted using Hybrid Single‐Particle Lagrangian Integrated Trajectory (HYSPLIT) backwards trajectories, and the intensity as well as duration of heavy rainfall events. We find that while the synoptic‐scale pattern that produces ARs is similar to other AR studies, there are some differences in the synoptic‐scale environments consistent with the study of inter‐annual variability in this region. Also, while much of the moisture ingested by ARs comes from the Gulf and Caribbean, if moisture comes from the Atlantic region there is a potential for larger rainfall events. Finally, an analysis of upper‐air soundings shows some key differences between warm and cold season ARs, and possibly inter‐annual variations as well.

ABSTRACTMost pesticides applied in the United States have labels that include language prohibiting application during temperature inversions. This restriction, which is well known and is followed by aerial pesticide applicators, has more recently become a focus for ground pesticide applicators. This is partially due to the recent introduction of genetically engineered soybean and cotton with tolerance to dicamba herbicide. Dicamba has been utilized for more than 50 years to control weeds in grain crops, such as corn. In 2017, dicamba was approved for use in dicamba-tolerant soybean and cotton. In 2017 and 2018, dicamba movement onto nontarget plants was substantial. As based on patterns of injury to nontolerant crops and time of applications, some of which occurred during the evening, inversions were likely contributors to off-target movement. Historically, most research on surface temperature inversions and pesticides focused on aerial applications. Research presented here focused on development of inversion profiles at atmospheric heights relevant to ground applications, which typically occur 46–107 cm above ground level (AGL). During the 2015–17 soybean growing seasons, data were collected at three heights AGL (46, 168, and 305 cm) in three soybean-producing regions of Missouri to characterize inversions. Over 600 inversions were characterized; all were nocturnal in nature. Inversions typically lasted overnight at two locations; duration varied at the third. The largest temperature difference recorded was 6°C. This research has resulted in real-time inversion monitoring that is available online to applicators (http://agebb.missouri.edu/weather/realTime/maps/index.php#temp_inversion), and the data generated can be utilized to improve accuracy of low-level inversion forecasting models.

Over the last six to seven decades, there has been a substantial increase in atmospheric research to better understand the dynamics and evolution of atmospheric blocking events. It is well known that atmospheric blocking serves as a catalyst for increasing the frequency of atmospheric flow regime stagnation and forecast unpredictability. This study built upon the results of previous work by expanding upon the findings of various climatologies and case studies. This work analyzes specific trends observed in association with atmospheric blocking predominantly across the central and eastern Pacific Ocean. Such trends include the relationship between the size, duration, and onset position of atmospheric blocking events and the frequency, duration, and intensity of heavy rainfall events across the central United States. A strong focus is placed on examining the duration and spatial extent of atmospheric blocking which has been found to influence the intensity of heavy rainfall events. The goal is to further bridge the gap between the location and duration of blocking highs and the intensity, duration, and frequency of heavy rainfall events which occur downstream of such blocking events.

An analysis of crop yields for the state of Missouri was completed to determine if an interannual or multidecadal variability existed as a result of the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). Corn and soybean yields were recorded in kilograms per hectare for each of the six climate regions of Missouri. An analysis using the Mokhov “method of cycles” demonstrated interannual, interdecadal, and multidecadal variations in crop yields. Cross-spectral analysis was used to determine which region was most impacted by ENSO and PDO influenced seasonal (April–September) temperature and precipitation. Interannual (multidecadal) variations found in the spectral analysis represent a relationship to ENSO (PDO) phase, while interdecadal variations represent a possible interaction between ENSO and PDO. Average crop yields were then calculated for each combination of ENSO and PDO phase, displaying a pronounced increase in corn and soybean yields when ENSO is warm and PDO is positive. Climate regions 1, 2, 4, and 6 displayed significant differences (p value of 0.10 or less) in yields between El Niño and La Niña years, representing 55–70 % of Missouri soybean and corn productivity, respectively. Final results give the opportunity to produce seasonal predictions of corn and soybean yields, specific to each climate region in Missouri, based on the combination of ENSO and PDO phases.

In the Midwestern United States, where a third of the world's maize crop is grown, there are few decision support tools available to help farmers and their advisors plan for an uncertain climatic future. Developing tools that are actually useful and usable to agricultural decision makers necessitates an interdisciplinary team of climate scientists, agronomists, computer scientists, and social scientists: With such diversity come varying levels of engagement (e.g. co-project director, student, technician, etc.) and experience working with farmers and/or serving in an official Extension capacity. Therefore working together to address this challenging issue is not straightforward. This paper reviews how a survey of a large interdisciplinary team working on developing decision support tools to ensure resilient maize production in this region identified differences between team members and helped improve team functioning and communication. Specifically the team survey revealed some important differences in how team members perceive farmers' use of climate information, the types of decisions that should be addressed with a tool, and how such tools should function. These differences can be primarily explained by disciplinary background and project role and have provided valuable opportunities to learn from each other and build consensus on decision support tools developed. The survey as a feed-back tool complements other team communication approaches and reminds the team of the need for continuous communication and frequent discussion of assumptions. (C) 2015 Elsevier B.V. All rights reserved.

Abstract Corn is the most widely grown crop in the Americas, with annual production in the United States of approximately 332 million metric tons. Improved climate forecasts, together with climate-related decision tools for corn producers based on these improved forecasts, could substantially reduce uncertainty and increase profitability for corn producers. The purpose of this paper is to acquaint climate information developers, climate information users, and climate researchers with an overview of weather conditions throughout the year that affect corn production as well as forecast content and timing needed by producers. The authors provide a graphic depicting the climate-informed decision cycle, which they call the climate forecast–decision cycle calendar for corn.

Long-term urban and rural climate data spanning January 1995 through October 2013 were analyzed to investigate the Urban Heat Island (UHI) effect in a representative mid-sized city of the central US. Locally distributed climate data were also collected at nested low density urban, recently developed, and high density urban monitoring sites from June through September 2013 to improve mechanistic understanding of spatial variability of the UHI effect based upon urban land use intensity. Long-term analyses (1995–2013) indicate significant differences (p < 0.001) between average air temperature (13.47 and 12.89 °C, at the urban and rural site respectively), relative humidity (69.11% and 72.51%, urban and rural respectively), and average wind speed (2.05 and 3.15 m/s urban and rural respectively). Significant differences (p < 0.001) between urban monitoring sites indicate an urban microclimate gradient for all climate variables except precipitation. Results of analysis of net radiation and soil heat flux data suggest distinct localized alterations in urban energy budgets due to land use intensity. Study results hold important implications for urban planners and land managers seeking to improve and implement better urban management practices. Results also reinforce the need for distributed urban energy balance investigations.

Widespread frost or freeze events can cause extreme economic losses to the agriculture, horticulture, and nursery industries. Coordinated advance notice of an imminent freeze event can help minimize these losses. Forecasters can issue headlines ahead of these events if damage to susceptible vegetation is possible. Combining expertise among the forecasters and the vegetation specialists can provide a community collaborative opportunity that will inform the risks, susceptibility, and environmental conditions associated with frost and freeze impacts. The Midwestern Regional Climate Center has become the facilitator of this community collaboration effort through the development of the online Vegetation Impact Program and Frost/Freeze Guidance Project. This paper presents the development of these initiatives along with early results and findings.

Abstract This work describes an evaluation of tropical cyclones (TCs) and depressions in order to determine if the El Niño Southern Oscillation (ENSO) may related to the recent rise of TC remnants affecting Missouri or if the variability is more sensitive to a long term Pacific Decadal Cycle. Sea surface temperatures (SST), mean sea level pressure (MSLP), the Pacific Decadal Oscillation (PDO), the Atlantic Multi-decadal Oscillation (AMO), the Quasi-Biennial Oscillation (QBO), and the (ENSO) were studied to determine possible correlations with the frequency of tropical remnants affecting Missouri. The study found a significant positive correlation between the frequencies of Missouri impacts per year to the frequency of Atlantic Ocean TCs. The more active the Atlantic Ocean basin is, the more times Missouri can expect to be impacted. TC paths were classified based on their direction of travel. TC remnants interacting with frontal boundaries took a more southwest to northeast track. Whereas TC remnants that entered a more zonal weather pattern traveled along a south to north path. Results found that the positive PDO (PDO one) 1938–1946 and 1977–1998 involved a total of 10 TCs affecting Missouri, an average of 0.32 events per year. The negative PDO (PDO two) 1947–1976 and 1999–present involved a combined result of 25 TCs affecting Missouri, an average of 0.57 events per year. A similar result is found for the AMO. A 2005 case study shows how the rare combination of elevated SSTs in the Gulf of Mexico, anomalously low MSLP, and the negative phase QBO led to increased TC activity in the tropical Atlantic Ocean. Also, the frequency of TC affecting Missouri since 1938 was compared to the type of ENSO cycle. La Niña periods produced an average of 0.37, El Niño produced 0.31, and Neutral periods produced 0.58 TC per year. The frequency of Missouri impacts was separated by month during each respective ENSO cycle. Chi-squared tests show - with four degrees of freedom and a value of 0.99 - that the distributions of TC per month versus ENSO cycle are not significantly different. Thus, Missouri is impacted more often by TCs during August and September regardless of ENSO phase. The conclusions suggest that Missouri TC climatology is more sensitive to long term PDO cycle fluctuations, and the resulting frequency of TC in the Atlantic Ocean, than to short term ENSO variability.

On 1 March 2006, Missouri became the 11th state to join the Community Collaborative Rain, Hail, and Snow Network (CoCoRaHS). CoCoRaHS is a national volunteer network of individuals who have agreed to measure and report precipitation observations daily. This program was established in 1998 by the Colorado State Climate Office. On 12 March, 2006 CoCoRaHs quickly demonstrated its usefulness during the severe weather events of that day when there were several reports of large hail. Since then, Missouri CoCoRaHS network receives about 250 reports per day. This data can be used to study severe weather events such as the passage of Tropical Depression Gustav and Tropical Storm Ike through Missouri over a 10 day period bookended by 4 and 14 September 2008. Here we will compare the CoCoRaHS volunteer rainfall totals to RADAR derived estimates taken from the National Weather Service (NWS) as well as the Cooperative Site measurements. CoCoRaHS data was even incorporated by the local NWS to summarize these events. CoCoRaHS data is currently used by all six NWS offices and the four River Forecast Centers that serve the state of Missouri as well as by other state and federal agencies and several television stations. The data have been used to dispatch flash flood information to the NWS and to make flood and drought assessments for the Missouri departments of Agriculture and Natural Resources. Public works departments, insurance companies, contractors and farmers have also used the data for documentation and management decisions. The Missouri CoCoRaHS network has proven to be a very valuable tool for precipitation measurement, and here we demonstrate this by comparing the CoCoRaHS data to different types of precipitation graphics provided by the NWS.

In a typical weather broadcast, observed precipitation information such as the daily amount that fell and the accumulated monthly total are shown and compared to the mean monthly average or “normal” precipitation. Such information, however, may not adequately describe whether or not that particular month is fairly typical for the time of year or truly an unusual occurrence. Here it is shown that monthly average precipitation may not be representative of the typical value for a particular month at all. Thus it is suggested that the presentation of precipitation information can be augmented with elementary statistical information in order to give a more meaningful presentation of precipitation information without the need to explain the basis of such statistical information. A study of the climatological behavior of monthly precipitation values over a 118-year period for Columbia, Missouri is performed in order to provide the rationale for displaying "typical" precipitation ranges.

Recent studies have attempted to link variations in global circulation (e.g., Wallace and Gutzler, 1981; Gershanov and Barnett, 1998; Wiedenmann et al. 2002), or local (and regional) climate variations (e.g., Kung and Chern, 1995 [hereafter KC95]; Kunkel and Angel, 1999; Lupo et al., 2007) with interannual and interdecadal variations in sea surface temperatures (SSTs) and pressures in the Pacific Ocean basin and/or the changes in the character of the atmospheric and oceanic circulations in the Atlantic Ocean Basin (e.g., Hu et al., 1998). The interactions between the atmosphere and oceans are important processes to consider when attempting to either understand the relevant physics of the earth’s climate system or to make long-range forecasts (e.g, Anderson et al., 1999; Barnston et al., 2005). The dominant interannual variations in global and regional climate characteristics are largely influenced by El Nino and Southern Oscillation (ENSO) modes (e.g., Mokhov et al., 2000, 2004). It is known that tropical SST distributions and “anomalous” SST distributions have a large impact on the weather and climate by changing heat and mass distributions of the troposphere. Through this influence, SSTs can ultimately alter the prevailing wind patterns over a large portion of the globe (e.g., Namias 1982, 1983; Enfield and Mestas-Nunez, 1999; Mestas-Nunez and Enfield, 1999, 2001; Wiedenmann et al., 2002). This in turn can impact the frequency, occurrence, and intensity of such phenomena as mid-latitude cyclones (e.g., Key and Chan, 1999), tropical cyclones (e.g., Gray, 1984) and blocking anticyclones (e.g., Wiedenmann et al., 2002). However, there are studies (e.g, Enfield and Mestas-Nunez, 1999; Mestas-Nunez and Enfield, 1999, 2001; Kushnir et al., 2002) that point out that midlatitude SSTs may not be very influential on mid-latitude circulations. Nonetheless, the influence of tropical SSTs on the mid-Missouri area regional climate have been demonstrated, albeit indirectly, via the impacts on snowfall regimes (e.g., Lupo et al., 2005), tornado occurrences (Akyuz et al., 2004), and temperature and precipitation regimes (e.g., Hu et al., 1998; Lupo et al., 2007). KC95 used principal component analysis to extract the __________________________________________________ *Corresponding author address: Anthony R. Lupo, Department of Soil, Environmental, and Atmospheric Science, 302 E ABNR Building, University of Missouri, Columbia, MO 65211. E-mail: LupoA@missouri.edu. large-scale modes of monthly mean global SST anomalies and the Northern Hemisphere tropospheric circulation anomalies during the period 1955 – 1993. The KC95 study provided an archive which can be used as guidance for long-range forecasting applications (e.g., forecasting by the use of analogs and/or contingency tables). This analysis was then extended to 2005 by Lupo et al. (2007). A by-product of these analyses demonstrate that global SST anomalies could be classified into one of seven distinct pattern types (A – G). Each of these was correlated with corresponding Northern Hemisphere tropospheric mass distributions or flow anomalies, and in subsequent work, correlated with surface climatic characteristics in mid-Missouri (Lee and Kung, 2000). KC95 and Lupo et al. (2007) also noted that anomaly types (clusters) A, B, E, and G (C, D, and F) are representative of La Nina or neutral (El Nino) type SST distributions within the Pacific Ocean basin. They also demonstrated that clusters A-D dominated the negative phase of the Pacific Decadal Oscillation (PDO) (1955 – 1977, and 1999-present), while E and F type clusters dominated the middle portion (1977-1998). Thus, this work has two primary objectives. First, the work of Lupo et al. (2007) will be discussed (section 2 and 3) and this includes an analysis of SST anomaly types and their correlation to monthly temperatures and precipitation in the mid-Mississippi valley region as represented by a time series from the Columbia regional Airport. Their work is then extended here (section 4) to discuss the synoptic-scale flow regimes associated with prolonged SST anomaly distributions of each of the seven types discussed above. This work then examines the usefulness of these results in making long range forecasts made by the long range prediction group at the University of Missouri – Columbia, and the verification of these forecasts (section 5). This includes a discussion of summer season blocking in the East Pacific and the relationship to temperatures and precipitation in our study region. We will demonstrate that these forecasts are better than a commonly used baseline forecast (climatology).

Sixteen years ago, the University of Missouri's Extension Commercial Agriculture Program established a small mesonet in Missouri named the Extension Commercial Agriculture Automated Weather Station Network. Environmental variables including temperature, relative humidity, wind speed, wind direction, solar radiation, soil temperature and precipitation were collected on an hourly and daily basis. The vision for these weather stations was to support high technology agriculture and preservation of the environment. Today, the mesonet has grown to 27 weather stations across the Show-Me state (Figure1.1) and the vision has exceeded all its expectations. In hindsight, the network has not only been successful in the agricultural realm, but its application has transcended numerous other vocations and interests and has become an important environmental data resource for the citizens of Missouri.

An unprecedented freeze occurred between 4 and 10 Apr. 2007, causing extensive crop loss across a large area of the United States. This event occurred late in the spring and temperatures were unusually low for an extended period. Low-temperature injury on small fruit plants was reported in 21 states. Missouri and Arkansas experienced the highest estimated percentages of crop loss of grape (Vitis spp.), strawberry (Fragraria xananassa Duch.), blueberry (Vaccinium spp.), and blackberry (Rubus subgenus Rubus Watson). Kentucky and Tennessee also reported high percentages of small fruit crop loss. Temperatures preceding the freeze event in the affected region were unusually warm and many of the crops were at a more advanced stage of growth than they would have been under more usual conditions. Although frost/freeze warnings were issued, the terminology used by different weather forecasters was inconsistent. Growers used various cold protection methods, but these were generally ineffective because of the stage of plant development and/or the advective nature of the freeze. Actual grape and blueberry crop losses may not be known for several years because of secondary injury to plant tissues from various pathogens.

The effect of urban environments on local temperature and precipitation distributions have been examined in the past (e.g., Changnon, 1981; Segal and Arritt, 1992; Melhuish and Pedder, 1998). These studies have usually focused on cities that have very large populations. The "heat-island effect" produced by such cities can have profound impact, sometimes adversely, on the well-being of its residents (e.g., Karl and Knight, 1997). Studies have also examined the impact of agricultural practices on local environments (e.g., Raymond et al. 1994). The study of regional heat islands is a topic that has enjoyed renewed interest lately, especially within the context of global climate change (e.g., Gaffen and Ross, 1998; NAS, 2000; IPCC, 2001). Additionally, there are many examples of studies that explore the impact on local atmospheric phenomena by the unique distribution of regional geography (e.g., Colle and Mass, 1996; Doeskin and Weaver, 2000). There is published work (e.g., Melhuish and Pedder, 1998; Pinho and Manso-Orgaz, 2000) that demonstrating that medium-sized and small urban areas may also be responsible for heat-island effects, although these would not be expected to be as pronounced as those of larger cities. There is also anecdotal evidence available to suggest that Columbia, MO, is responsible for a detectable heat-island effect. Columbia would be at the smaller end of the spectrum of urbanized areas and is composed of a downtown area and the University of Missouri campus. Intensive residential and retail development flank these two core regions. There are two main objectives for the COlumbia Heat Island eXperiment (COHIX). The first was to determine the extent of the heat-island effect produced by Columbia, MO. Thermometers and rain gauges were deployed in and around the city to measure this effect and the variation in the strength of the heat-island with respect to seasonal variations. Additionally, precipitation was measured in order to determine whether there is an impact on local precipitation fields. The second was to provide undergraduate students in the Atmospheric Sciences Program at the University of Missouri with an opportunity to participate in the process of scientific discovery and research and to expose them to the principles of meteorological instrumentation and research. The experiment then served as a starting point for developing an experimentation/instrumentation course in the program. _________________________________________________ *Corresponding author address: Anthony R. Lupo, Department of Soil and Atmospheric Sciences, 112 Gentry Hall, University of Missouri-Columbia, Columbia, MO 65211. E-mail: LupoA@missouri.edu. 2. DATA AND METHODOLOGY