scholarly journals An Objective High-Resolution Hail Climatology of the Contiguous United States

2012 ◽  
Vol 27 (5) ◽  
pp. 1235-1248 ◽  
Author(s):  
John L. Cintineo ◽  
Travis M. Smith ◽  
Valliappa Lakshmanan ◽  
Harold E. Brooks ◽  
Kiel L. Ortega
Keyword(s):  
United States ◽  
High Resolution ◽  
Spatial Resolution ◽  
Great Plains ◽  
Economic Losses ◽  
Climatic Data ◽  
Southeast United States ◽  
Severe Storms ◽  
Severe Thunderstorms ◽  
Spatial And Temporal Characteristics

Abstract The threat of damaging hail from severe thunderstorms affects many communities and industries on a yearly basis, with annual economic losses in excess of $1 billion (U.S. dollars). Past hail climatology has typically relied on the National Oceanic and Atmospheric Administration/National Climatic Data Center’s (NOAA/NCDC) Storm Data publication, which has numerous reporting biases and nonmeteorological artifacts. This research seeks to quantify the spatial and temporal characteristics of contiguous United States (CONUS) hail fall, derived from multiradar multisensor (MRMS) algorithms for several years during the Next-Generation Weather Radar (NEXRAD) era, leveraging the Multiyear Reanalysis of Remotely Sensed Storms (MYRORSS) dataset at NOAA’s National Severe Storms Laboratory (NSSL). The primary MRMS product used in this study is the maximum expected size of hail (MESH). The preliminary climatology includes 42 months of quality controlled and reprocessed MESH grids, which spans the warm seasons for four years (2007–10), covering 98% of all Storm Data hail reports during that time. The dataset has 0.01° latitude × 0.01° longitude × 31 vertical levels spatial resolution, and 5-min temporal resolution. Radar-based and reports-based methods of hail climatology are compared. MRMS MESH demonstrates superior coverage and resolution over Storm Data hail reports, and is largely unbiased. The results reveal a broad maximum of annual hail fall in the Great Plains and a diminished secondary maximum in the Southeast United States. Potential explanations for the differences in the two methods of hail climatology are also discussed.

scholarly journals Characterizing severe weather potential in synoptically weakly forced thunderstorm environments

2017 ◽  
Author(s):  
Paul W. Miller ◽  
Thomas L. Mote
Keyword(s):  
United States ◽  
High Resolution ◽  
Numerical Model ◽  
Model Error ◽  
Severe Weather ◽  
Forecasting Model ◽  
Weather Event ◽  
Southeast United States ◽  
Accurate Representation ◽  
Severe Weather Event

Abstract. Weakly forced thunderstorms (WFTs), short-lived convection forming in synoptically quiescent regimes, are a contemporary forecasting challenge. The convective environments that support severe WFTs are often similar to those that yield only nonsevere WFTs, and additionally, only a small proportion individual WFTs will ultimately produce severe weather. The purpose of this study is to better characterize the relative severe weather potential in these settings as a function of the convective environment. Thirty near-storm convective parameters for > 200 000 WFTs in the Southeast United States are calculated from a high-resolution numerical forecasting model, the Rapid Refresh (RAP). For each parameter, the relative likelihood of WFT days with at least one severe weather event is assessed along a moving threshold. Parameters (and the values of them) that reliably separate severe-weather-supporting from nonsevere WFT days are highlighted. Only two convective parameters, vertical totals (VT) and total totals (TT), appreciably differentiate severe-wind-supporting and severe-hail-supporting days from nonsevere WFT days. When VTs exceeded values between 24.6–25.1 °C or TTs between 46.5–47.3 °C, severe-wind days were roughly 5 × more likely. Meanwhile, severe-hail days became roughly 10 × more likely when VTs exceeded 24.4–26.0 °C or TTs exceeded 46.3–49.2 °C. The stronger performance of VT and TT is partly attributed to the more accurate representation of these parameters in the numerical model. Under-reporting of severe weather and model error are posited to exacerbate the forecasting challenge by obscuring the subtle convective environmental differences enhancing storm severity.

A remote sensing approach for evaluating regional-scale topsoil loss in the Midwestern United States

2020 ◽  
Author(s):  
Isaac Larsen ◽  
Evan Thaler ◽  
Qian Yu
Keyword(s):  
United States ◽  
Remote Sensing ◽  
High Resolution ◽  
Soil Erosion ◽  
Carbon Cycle ◽  
Soil Loss ◽  
Agricultural Landscapes ◽  
Economic Losses ◽  
Corn Belt ◽  
Midwestern United States

<p>Soil erosion in agricultural landscapes reduces crop yields and influences the global carbon cycle. However, the magnitude of historical topsoil loss remains poorly quantified at large, regional spatial scales, hindering predictions of economic losses to farmers and quantification of the role soil erosion plays in the carbon cycle. We focus on one of the world’s most productive agricultural regions, the Corn Belt of the Midwestern United States and use a novel spectral remote sensing method to map areas of complete topsoil loss in agricultural fields. Using high-resolution satellite images and the association between topsoil loss and topographic curvature, we use high resolution LiDAR topographic data to scale-up soil loss predictions to 3.7x10<sup>5</sup> km<sup>2</sup> of the Corn Belt. Our results indicate 34±12% of the region has completely lost topsoil as a result of agriculturally-accelerated erosion. Soil loss is most prevalent on convex slopes, and hilltops throughout the region are often completely denuded of topsoil indicating that tillage is a major driver of erosion, yet tillage erosion is not simulated in models used to assess soil loss trends in the U.S. We estimate that soil regenerative farming practices could restore 16±4.4 Pg of carbon to the exposed subsoil in the region. Soil regeneration would offset at least $2.5±0.3 billion in annual economic losses to farmers while generating a carbon sink equivalent to 8±3 years of U.S. CO<sub>2</sub> emissions, or ~14% of the global soil carbon lost since the advent of agriculture.  </p>

scholarly journals NOAA’s 1981–2010 U.S. Climate Normals: Monthly Precipitation, Snowfall, and Snow Depth

2013 ◽  
Vol 52 (11) ◽  
pp. 2377-2395 ◽  
Author(s):  
Imke Durre ◽  
Michael F. Squires ◽  
Russell S. Vose ◽  
Xungang Yin ◽  
Anthony Arguez ◽  
...  
Keyword(s):  
United States ◽  
Pacific Northwest ◽  
Great Plains ◽  
Snow Depth ◽  
State Of The Art ◽  
The United States ◽  
Climatic Data ◽  
Monthly Precipitation ◽  
National Climatic Data Center ◽  
The Caribbean

AbstractThe 1981–2010 “U.S. Climate Normals” released by the National Oceanic and Atmospheric Administration’s (NOAA) National Climatic Data Center include a suite of monthly, seasonal, and annual statistics that are based on precipitation, snowfall, and snow-depth measurements. This paper describes the procedures used to calculate the average totals, frequencies of occurrence, and percentiles that constitute these normals. All parameters were calculated from a single, state-of-the-art dataset of daily observations, taking care to produce normals that were as representative as possible of the full 1981–2010 period, even when the underlying data records were incomplete. In the resulting product, average precipitation totals are available at approximately 9300 stations across the United States and parts of the Caribbean Sea and Pacific Ocean islands. Snowfall and snow-depth statistics are provided for approximately 5300 of those stations, as compared with several hundred stations in the 1971–2000 normals. The 1981–2010 statistics exhibit the familiar climatological patterns across the contiguous United States. When compared with the same calculations for 1971–2000, the later period is characterized by a smaller number of days with snow on the ground and less total annual snowfall across much of the contiguous United States; wetter conditions over much of the Great Plains, Midwest, and northern California; and drier conditions over much of the Southeast and Pacific Northwest. These differences are a reflection of the removal of the 1970s and the addition of the 2000s to the 30-yr-normals period as part of this latest revision of the normals.

scholarly journals Tornado Damage Rating Probabilities Derived from WSR-88D Data

2017 ◽  
Vol 32 (4) ◽  
pp. 1509-1528 ◽  
Author(s):  
Richard L. Thompson ◽  
Bryan T. Smith ◽  
Jeremy S. Grams ◽  
Andrew R. Dean ◽  
Joseph C. Picca ◽  
...  
Keyword(s):  
United States ◽  
Great Plains ◽  
Probability Distributions ◽  
Rotational Velocity ◽  
The United States ◽  
Low Level ◽  
Convective Systems ◽  
Severe Thunderstorms ◽  
Damage Indicators ◽  
Tornado Damage

Abstract Previous work with observations from the NEXRAD (WSR-88D) network in the United States has shown that the probability of damage from a tornado, as represented by EF-scale ratings, increases as low-level rotational velocity increases. This work expands on previous studies by including reported tornadoes from 2014 to 2015, as well as a robust sample of nontornadic severe thunderstorms [≥1-in.- (2.54 cm) diameter hail, thunderstorm wind gusts ≥ 50 kt (25 m s−1), or reported wind damage] with low-level cyclonic rotation. The addition of the nontornadic sample allows the computation of tornado damage rating probabilities across a spectrum of organized severe thunderstorms represented by right-moving supercells and quasi-linear convective systems. Dual-polarization variables are used to ensure proper use of velocity data in the identification of tornadic and nontornadic cases. Tornado damage rating probabilities increase as low-level rotational velocity Vrot increases and circulation diameter decreases. The influence of height above radar level (or range from radar) is less obvious, with a muted tendency for tornado damage rating probabilities to increase as rotation (of the same Vrot magnitude) is observed closer to the ground. Consistent with previous work on gate-to-gate shear signatures such as the tornadic vortex signature, easily identifiable rotation poses a greater tornado risk compared to more nebulous areas of cyclonic azimuthal shear. Additionally, tornado probability distributions vary substantially (for similar sample sizes) when comparing the southeast United States, which has a high density of damage indicators, to the Great Plains, where damage indicators are more sparse.

Convective Modes for Significant Severe Thunderstorms in the Contiguous United States. Part I: Storm Classification and Climatology

2012 ◽  
Vol 27 (5) ◽  
pp. 1114-1135 ◽  
Author(s):  
Bryan T. Smith ◽  
Richard L. Thompson ◽  
Jeremy S. Grams ◽  
Chris Broyles ◽  
Harold E. Brooks
Keyword(s):  
United States ◽  
Great Plains ◽  
Radar Data ◽  
High Plains ◽  
Deep South ◽  
Southern Great Plains ◽  
Convective Systems ◽  
Severe Thunderstorms ◽  
Wind Events ◽  
Convective Mode

Abstract Radar-based convective modes were assigned to a sample of tornadoes and significant severe thunderstorms reported in the contiguous United States (CONUS) during 2003–11. The significant hail (≥2-in. diameter), significant wind (≥65-kt thunderstorm gusts), and tornadoes were filtered by the maximum event magnitude per hour on a 40-km Rapid Update Cycle model horizontal grid. The filtering process produced 22 901 tornado and significant severe thunderstorm events, representing 78.5% of all such reports in the CONUS during the sample period. The convective mode scheme presented herein begins with three radar-based storm categories: 1) discrete cells, 2) clusters of cells, and 3) quasi-linear convective systems (QLCSs). Volumetric radar data were examined for right-moving supercell (RM) and left-moving supercell characteristics within the three radar reflectivity designations. Additional categories included storms with marginal supercell characteristics and linear hybrids with a mix of supercell and QLCS structures. Smoothed kernel density estimates of events per decade revealed clear geographic and seasonal patterns of convective modes with tornadoes. Discrete and cluster RMs are the favored convective mode with southern Great Plains tornadoes during the spring, while the Deep South displayed the greatest variability in tornadic convective modes in the fall, winter, and spring. The Ohio Valley favored a higher frequency of QLCS tornadoes and a lower frequency of RM compared to the Deep South and the Great Plains. Tornadoes with nonsupercellular/non-QLCS storms were more common across Florida and the high plains in the summer. Significant hail events were dominated by Great Plains supercells, while variations in convective modes were largest for significant wind events.

scholarly journals Monitoring Drought over the Conterminous United States Using MODIS and NCEP Reanalysis-2 Data

2010 ◽  
Vol 49 (8) ◽  
pp. 1665-1680 ◽  
Author(s):  
Yunjun Yao ◽  
Shunlin Liang ◽  
Qiming Qin ◽  
Kaicun Wang
Keyword(s):  
United States ◽  
Spatial Resolution ◽  
Great Plains ◽  
Land Surface ◽  
Remote Sensing Data ◽  
Moisture Stress ◽  
Ncep Reanalysis ◽  
Southern Great Plains ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract Monitoring land surface drought using remote sensing data is a challenge, although a few methods are available. Evapotranspiration (ET) is a valuable indicator linked to land drought status and plays an important role in surface drought detection at continental and global scales. In this study, the evaporative drought index (EDI), based on the estimated actual ET and potential ET (PET), is described to characterize the surface drought conditions. Daily actual ET at 4-km resolution for April–September 2003–05 across the continental United States is estimated using a simple improved ET model with input solar radiation acquired by Moderate-Resolution Imaging Spectroradiometer (MODIS) at a spatial resolution of 4 km and input meteorological parameters from NCEP Reanalysis-2 data at a spatial resolution of 32 km. The PET is also calculated using some of these data. The estimated actual ET has been rigorously validated with ground-measured ET at six Enhanced Facility sites in the Southern Great Plains (SGP) of the Atmosphere Radiation Measurement Program (ARM) and four AmeriFlux sites. The validation results show that the bias varies from −11.35 to 27.62 W m−2 and the correlation coefficient varies from 0.65 to 0.86. The monthly composites of EDI at 4-km resolution during April–September 2003–05 are found to be in good agreement with the Palmer Z index anomalies, but the advantage of EDI is its finer spatial resolution. The EDI described in this paper incorporates information about energy fluxes in response to soil moisture stress without requiring too many meteorological input parameters, and performs well in assessing drought at continental scales.

scholarly journals Severe Convective Storms across Europe and the United States. Part II: ERA5 Environments Associated with Lightning, Large Hail, Severe Wind, and Tornadoes

2020 ◽  
Vol 33 (23) ◽  
pp. 10263-10286 ◽  
Author(s):  
Mateusz Taszarek ◽  
John T. Allen ◽  
Tomáš Púčik ◽  
Kimberly A. Hoogewind ◽  
Harold E. Brooks
Keyword(s):  
United States ◽  
Great Plains ◽  
Wind Shear ◽  
The United States ◽  
Severe Weather ◽  
Convective Initiation ◽  
Local Maxima ◽  
Severe Thunderstorms ◽  
Lightning Detection ◽  
Lapse Rates

AbstractIn this study we investigate convective environments and their corresponding climatological features over Europe and the United States. For this purpose, National Lightning Detection Network (NLDN) and Arrival Time Difference long-range lightning detection network (ATDnet) data, ERA5 hybrid-sigma levels, and severe weather reports from the European Severe Weather Database (ESWD) and Storm Prediction Center (SPC) Storm Data were combined on a common grid of 0.25° and 1-h steps over the period 1979–2018. The severity of convective hazards increases with increasing instability and wind shear (WMAXSHEAR), but climatological aspects of these features differ over both domains. Environments over the United States are characterized by higher moisture, CAPE, CIN, wind shear, and midtropospheric lapse rates. Conversely, 0–3-km CAPE and low-level lapse rates are higher over Europe. From the climatological perspective severe thunderstorm environments (hours) are around 3–4 times more frequent over the United States with peaks across the Great Plains, Midwest, and Southeast. Over Europe severe environments are the most common over the south with local maxima in northern Italy. Despite having lower CAPE (tail distribution of 3000–4000 J kg−1 compared to 6000–8000 J kg−1 over the United States), thunderstorms over Europe have a higher probability for convective initiation given a favorable environment. Conversely, the lowest probability for initiation is observed over the Great Plains, but, once a thunderstorm develops, the probability that it will become severe is much higher compared to Europe. Prime conditions for severe thunderstorms over the United States are between April and June, typically from 1200 to 2200 central standard time (CST), while across Europe favorable environments are observed from June to August, usually between 1400 and 2100 UTC.

scholarly journals An Analysis of the Warm-Season Diurnal Cycle over the Continental United States and Northern Mexico in General Circulation Models

2007 ◽  
Vol 8 (3) ◽  
pp. 344-366 ◽  
Author(s):  
Myong-In Lee ◽  
Siegfried D. Schubert ◽  
Max J. Suarez ◽  
Isaac M. Held ◽  
Ngar-Cheung Lau ◽  
...  
Keyword(s):  
United States ◽  
Great Plains ◽  
Diurnal Cycle ◽  
Rocky Mountains ◽  
General Circulation ◽  
Warm Season ◽  
General Circulation Models ◽  
Surface Boundary ◽  
Southeast United States ◽  
Northern Mexico

Abstract The diurnal cycle of warm-season rainfall over the continental United States and northern Mexico is analyzed in three global atmospheric general circulation models (AGCMs) from NCEP, GFDL, and the NASA Global Modeling Assimilation Office (GMAO). The results for each model are based on an ensemble of five summer simulations forced with climatological sea surface temperatures. Although the overall patterns of time-mean (summer) rainfall and low-level winds are reasonably well simulated, all three models exhibit substantial regional deficiencies that appear to be related to problems with the diurnal cycle. Especially prominent are the discrepancies in the diurnal cycle of precipitation over the eastern slopes of the Rocky Mountains and adjacent Great Plains, including the failure to adequately capture the observed nocturnal peak. Moreover, the observed late afternoon–early evening eastward propagation of convection from the mountains into the Great Plains is not adequately simulated, contributing to the deficiencies in the diurnal cycle in the Great Plains. In the southeast United States, the models show a general tendency to rain in the early afternoon—several hours earlier than observed. Over the North American monsoon region in the southwest United States and northern Mexico, the phase of the broad-scale diurnal convection appears to be reasonably well simulated, though the coarse resolution of the runs precludes the simulation of key regional phenomena. All three models employ deep convection schemes that assume fundamentally the same buoyancy closure based on simplified versions of the Arakawa–Schubert scheme. Nevertheless, substantial differences between the models in the diurnal cycle of convection highlight the important differences in their implementations and interactions with the boundary layer scheme. An analysis of local diurnal variations of convective available potential energy (CAPE) shows an overall tendency for an afternoon peak—a feature well simulated by the models. The simulated diurnal cycle of rainfall is in phase with the local CAPE variation over the southeast United States and the Rocky Mountains where the local surface boundary forcing is important in regulating the diurnal cycle of convection. On the other hand, the simulated diurnal cycle of rainfall tends to be too strongly tied to CAPE over the Great Plains, where the observed precipitation and CAPE are out of phase, implying that free atmospheric large-scale forcing plays a more important role than surface heat fluxes in initiating or inhibiting convection.

scholarly journals A Climatology of Weakly Forced and Pulse Thunderstorms in the Southeast United States

2017 ◽  
Vol 56 (11) ◽  
pp. 3017-3033 ◽  
Author(s):  
Paul W. Miller ◽  
Thomas L. Mote
Keyword(s):  
United States ◽  
Great Plains ◽  
Gulf Coast ◽  
Warm Season ◽  
Large Sample Size ◽  
Southeast United States ◽  
Modes Of Variability ◽  
Blue Ridge Mountains ◽  
Fall Line ◽  
River Valleys

AbstractWeakly forced thunderstorms (WFTs), convection forming in the absence of a synoptic forcing mechanism and its associated shear regime, are the dominant convective mode during the warm season in the southeast United States. This study uses 15 yr (2001–15) of warm-season (May–September) composite reflectivity images from 30 WSR-88D sites in the southeastern United States to detect WFTs and pulse thunderstorms, defined as WFTs associated with a severe weather event. Thunderstorms were identified as regions of contiguous reflectivities greater than or equal to 40 dBZ using connected neighborhoods labeling. Ward’s clustering was then performed upon the duration, size, strength, initiation time, and solidity of the approximately 1 900 000 thunderstorms. Of the 10 clusters of morphologically similar storms, five groups, containing 885 496 thunderstorms, were designated as WFTs. In line with previous work, WFT development mirrors landscape features, such as the Appalachian Mountains and Mississippi Delta. However, the large sample size also reveals more subtle nuances to the spatial distribution, such as decreases over river valleys and increases along the Atlantic fall line. The most active pulse thunderstorm region, the Blue Ridge Mountains, was displaced from the overall WFT maximum: the Florida Peninsula and Gulf Coast. Most pulse thunderstorms were associated with larger moisture values, particularly in the midlevels, which supported larger and longer-lasting WFT complexes. Synoptically, two distinct modes of variability yielded WFT-favorable environments: the intrusion of the Bermuda high from the east and the expansion of high pressure over the southern Great Plains from the west.

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