scholarly journals Precipitation Characteristics of Warm Season Weather Types in the Southeastern United States of America

Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1001
Author(s):  
Jian-Hua Qian ◽  
Brian Viner ◽  
Stephen Noble ◽  
David Werth
Keyword(s):  
United States ◽  
El Niño ◽  
Gulf Coast ◽  
El Nino ◽  
River Valley ◽  
Northern Great Plains ◽  
Ohio River ◽  
Fair Weather ◽  
Weather Types ◽  
Rainy Weather

Daily weather types (WTs) over the Southeast United States have been analyzed using 850 hPa winds from reanalysis data from March to October of 1979–2019. Six WTs were obtained. WTs 1–3 represent mid-latitude synoptic systems propagating eastward. WT4 is a summer-type pattern predominantly occurring in June–August, with the center of the North Atlantic Subtropical High (NASH) along the Gulf coast in the southern United States. WT5 is most frequent from August to middle October, with the NASH pushed further north and southerly winds over the northern Great Plains. An anticyclone centered at the Carolina coast characterizes WT6, which occurs in all months but is slightly more frequent in the spring and fall, especially in October, corresponding to fair weather in the region. WTs 1, 2 and 3 can persist for only a few days. WTs 4, 5 and 6 can have long spells of persistence. Besides self-persistence, the most observed progression loop is WT1 to WT2, to WT3, and then back to WT1, corresponding to eastward-propagating waves. WTs 4 and 5 are likely to show persistence, with long periods of consecutive days. WT6 usually persists but can also transfer to WT3, i.e., a change from fair weather in the Southeast U.S. to rainy weather in the Mississippi River Valley. A diurnal cycle of precipitation is apparent for each WT, especially over coastal plains. The nocturnal precipitation in central U.S. is associated with WT3. WTs 1–3 are more frequent in El Niño years, corresponding to stronger westerly wave activities and above normal rainfall in the Southeast U.S. in the spring. The positive rainfall anomaly in the Mississippi and Ohio River valley in El Niño years is also associated with more frequent WT3.

scholarly journals A Two-Tier Statistical Forecast Method for Agricultural and Resource Management Simulations

2008 ◽  
Vol 47 (6) ◽  
pp. 1573-1589 ◽  
Author(s):  
Steven A. Mauget ◽  
Jonghan Ko
Keyword(s):  
United States ◽  
Gulf Coast ◽  
Southern Oscillation ◽  
Winter Season ◽  
River Valley ◽  
Ohio River ◽  
Ohio River Valley ◽  
Central United States ◽  
Phase Systems ◽  
Simple Phase

Abstract Simple phase schemes to predict seasonal climate based on leading ENSO indicators can be used to estimate the value of forecast information in agriculture and watershed management, but may be limited in predictive skill. Here, a simple two-tier statistical method is used to hindcast seasonal precipitation over the continental United States, and the resulting skill is compared with that of ENSO phase systems based on Niño-3 sea surface temperature anomaly (SSTA) and Southern Oscillation index (SOI) persistence. The two-tier approach first predicts Niño-3 winter season SSTA, and then converts those predictions to categorical precipitation hindcasts via a simple phase translation process. The hindcasting problem used to make these comparisons is relevant to winter wheat production over the central United States. Thus, given the state of seasonal SOI and Niño-3 indicators defined before August, the goal is to predict the tercile category of the following November–March precipitation. Generally, it was found that the methods based on either predicted or persisted winter Niño-3 conditions were skillful over areas where ENSO affects U.S. winter precipitation—that is, the Southeast and the Gulf Coast, Texas, the southern and central plains, the Southwest, Northwest, and the Ohio River valley—and that the two-tier approach based on predicted Niño-3 conditions was more likely to provide the best skill. Skill based on SOI persistence was generally lower over many of those regions and was insignificant over broad parts of the central and southwest United States, but did lead the other methods over the Ohio River valley and the northwest. A more restrictive test of leading hindcast skill showed that the skill advantages of the two-tier approach over the central and western United States were not substantial, and mainly highlighted SOI persistence’s lack of skill over the central United States and leading skill over the Ohio River valley. However, two-tier hindcasts based on neural-network-predicted Niño-3 SSTA were clearly more skillful than both ENSO phase methods over areas of the Southeast. It is suggested that the relative skill advantage of the two-tier approach may be due in part to the use of arbitrary thresholds in ENSO phase systems.

Spatial and temporal trends and variabilities of hailstones in the United States Northern Great Plains and their possible attributions

2021 ◽  
pp. 1-53
Author(s):  
Jong-Hoon Jeong ◽  
Jiwen Fan ◽  
Cameron R. Homeyer
Keyword(s):  
United States ◽  
Water Vapor ◽  
Interannual Variability ◽  
Great Plains ◽  
El Niño ◽  
El Nino ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Northern Great Plains ◽  
Contributing Factors

AbstractFollowing on our study of hail for the Southern Great Plains (SGP), we investigated the spatial and temporal hail trends and variabilities for the Northern Great Plains (NGP) and the contributing factors for summers (June–August) focusing on the period of 2004–2016 using two independent hail datasets. Analysis for an extended period (1994–2016) with the hail reports was also conducted to more reliably investigate the contributing factors. Both severe hail (1″ < diameter ≤ 2″) and significant severe hail (SSH; diameter > 2″) were examined and similar results were obtained. The occurrence of hail over the NGP demonstrated a large interannual variability, with a positive slope overall. Spatially, the increase is mainly located in the western part of Nebraska, South Dakota, and North Dakota. We find the three major dynamical factors that most likely contribute to the hail interannual variability in the NGP are the El Niño-Southern Oscillation (ENSO), North Atlantic subtropical high (NASH), and low-level jet (LLJ). With a thermodynamical variable integrated water vapor transport that is strongly controlled by LLJ, the four factors can explain 78% of the interannual variability in the number of SSH reports. Hail occurrences in the La Niña years are higher than the El Niño years since the jet stream is stronger and NASH extends further into the southeastern United States, thereby strengthening the LLJ and in turn water vapor transport. Interestingly, the important factors impacting hail interannual variability over the NGP are quite different from those for the SGP, except for ENSO.

scholarly journals ENSO’s Modulation of Water Vapor Transport over the Pacific–North American Region

2015 ◽  
Vol 28 (9) ◽  
pp. 3846-3856 ◽  
Author(s):  
Hye-Mi Kim ◽  
Michael A. Alexander
Keyword(s):  
United States ◽  
El Niño ◽  
North Pacific ◽  
Moisture Transport ◽  
El Nino ◽  
Tropical Pacific ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Southwestern United States ◽  
The Pacific

Abstract The vertically integrated water vapor transport (IVT) over the Pacific–North American sector during three phases of ENSO in boreal winter (December–February) is investigated using IVT values calculated from the Climate Forecast System Reanalysis (CFSR) during 1979–2010. The shift of the location and sign of sea surface temperature (SST) anomalies in the tropical Pacific Ocean leads to different atmospheric responses and thereby changes the seasonal mean moisture transport into North America. During eastern Pacific El Niño (EPEN) events, large positive IVT anomalies extend northeastward from the subtropical Pacific into the northwestern United States following the anomalous cyclonic flow around a deeper Aleutian low, while a southward shift of the cyclonic circulation during central Pacific El Niño (CPEN) events induces the transport of moisture into the southwestern United States. In addition, moisture from the eastern tropical Pacific is transported from the deep tropical eastern Pacific into Mexico and the southwestern United States during CPEN. During La Niña (NINA), the seasonal mean IVT anomaly is opposite to that of two El Niño phases. Analyses of 6-hourly IVT anomalies indicate that there is strong moisture transport from the North Pacific into the northwestern and southwestern United States during EPEN and CPEN, respectively. The IVT is maximized on the southeastern side of a low located over the eastern North Pacific, where the low is weaker but located farther south and closer to shore during CPEN than during EPEN. Moisture enters the southwestern United States from the eastern tropical Pacific during NINA via anticyclonic circulation associated with a ridge over the southern United States.

scholarly journals Physiologic Specialization of Puccinia triticina on Wheat in the United States in 2013

Plant Disease ◽  
2015 ◽  
Vol 99 (9) ◽  
pp. 1261-1267 ◽  
Author(s):  
J. A. Kolmer ◽  
M. E. Hughes
Keyword(s):  
United States ◽  
Winter Wheat ◽  
Leaf Rust ◽  
Great Plains ◽  
Puccinia Triticina ◽  
The United States ◽  
Northern Great Plains ◽  
Ohio River ◽  
Ohio Valley ◽  
Red Winter Wheat

Collections of Puccinia triticina were obtained from rust-infected leaves provided by cooperators throughout the United States and from wheat fields and breeding plots by USDA-ARS personnel and cooperators in the Great Plains, Ohio River Valley, and southeastern states in order to determine the virulence of the wheat leaf rust population in 2013. Single uredinial isolates (490 total) were derived from the collections and tested for virulence phenotype on 20 lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes. In 2013, 79 virulence phenotypes were described in the United States. Virulence phenotypes MBTNB, TNBGJ, and MCTNB were the three most common phenotypes. Phenotypes MBTNB and MCTNB are both virulent to Lr11, and MCTNB is virulent to Lr26. MBTNB and MCTNB were most common in the soft red winter wheat region of the southeastern states and Ohio Valley. Phenotype TNBGJ is virulent to Lr39/41 and was widely distributed throughout the hard red winter wheat region of the Great Plains. Isolates with virulence to Lr11, Lr18, and Lr26 were common in the southeastern states and Ohio Valley region. Isolates with virulence to Lr21, Lr24, and Lr39/41 were frequent in the hard red wheat region of the southern and northern Great Plains.

scholarly journals Precipitation Prediction Skill for the West Coast United States: From Short to Extended Range

2018 ◽  
Vol 32 (1) ◽  
pp. 161-182 ◽  
Author(s):  
Baoxiang Pan ◽  
Kuolin Hsu ◽  
Amir AghaKouchak ◽  
Soroosh Sorooshian ◽  
Wayne Higgins
Keyword(s):  
United States ◽  
West Coast ◽  
El Niño ◽  
El Nino ◽  
The United States ◽  
Prediction Skill ◽  
Precipitation Prediction ◽  
Skill Scores ◽  
Extended Range ◽  
To Receive

Abstract Precipitation variability significantly influences the heavily populated West Coast of the United States, raising the need for reliable predictions. We investigate the region’s short- to extended-range precipitation prediction skill using the hindcast database of the Subseasonal-to-Seasonal Prediction Project (S2S). The prediction skill–lead time relationship is evaluated, using both deterministic and probabilistic skill scores. Results show that the S2S models display advantageous deterministic skill at week 1. For week 2, prediction is useful for the best-performing model, with a Pearson correlation coefficient larger than 0.6. Beyond week 2, predictions generally provide little useful deterministic skill. Sources of extended-range predictability are investigated, focusing on El Niño–Southern Oscillation (ENSO) and the Madden–Julian oscillation (MJO). We found that periods of heavy precipitation associated with ENSO are more predictable at the extended range period. During El Niño years, Southern California tends to receive more precipitation in late winter, and most models show better extended-range prediction skill. On the contrary, during La Niña years Oregon tends to receive more precipitation in winter, with most models showing better extended-range skill. We believe the excessive precipitation and improved extended-range prediction skill are caused by the meridional shift of baroclinic systems as modulated by ENSO. Through examining precipitation anomalies conditioned on the MJO, we verified that active MJO events systematically modulate the area’s precipitation distribution. Our results show that most models do not represent the MJO or its associated teleconnections, especially at phases 3–4. However, some models exhibit enhanced extended-range prediction skills under active MJO conditions.

scholarly journals Stewart's Wilt Reactions of an International Collection of Zea mays Germ Plasm Inoculated with Erwinia stewartii

Plant Disease ◽  
2000 ◽  
Vol 84 (8) ◽  
pp. 901-906 ◽  
Author(s):  
Jerald K. Pataky ◽  
Lindsey J. du Toit ◽  
Noah D. Freeman
Keyword(s):  
United States ◽  
Germ Plasm ◽  
Sweet Corn ◽  
The United States ◽  
River Valley ◽  
Ohio River ◽  
Ohio River Valley ◽  
The World ◽  
The Mean ◽  
Stewart's Wilt

Maize accessions were evaluated in 1997, 1998, and 1999 to identify additional sources of Stewart's wilt resistance and to determine if reactions differed among accessions collected from various regions of the United States and throughout the world. The distributions of Stewart's wilt reactions rated from 1 (no appreciable spread of symptoms) to 9 (dead plants) were relatively similar among groups of accessions from all regions of the world except for those from the Mid-Atlantic/Ohio River Valley region of the United States, the southern United States, and the northeastern United States. The mean and median Stewart's wilt rating for 1,991 accessions evaluated in 1997 was 4. The mean Stewart's wilt rating for 245 accessions collected from the Mid-Atlantic/Ohio River Valley region was 3.1, which was significantly lower than that for accessions from all other regions. The mean rating for accessions from the southern United States was 3.7, which also was lower than mean ratings for accessions from all other regions. Ratings from trials in 1997 and 1998 were highly correlated (r = 0.87) for 292 accessions and 15 sweet corn hybrid checks evaluated in both years. Of 20 accessions rated below 2 in 1997 and 1998, seven were from Virginia, seven were from the Ohio River Valley or central Corn Belt of the United States, four were from the northern or western Corn Belt of the United States, and two were from Spain. Ratings for these accessions ranged from 1.7 to 3.1 in 1999. Ratings ranged from 2.6 to 3.7 for F1 hybrids of these accessions crossed with one of two susceptible sweet corn inbreds, CrseW30 or Crse16, which were rated 5.7 and 5.4, respectively. Based on the reactions of this collection of germ plasm, it appears that high levels of Stewart's wilt resistance are prevalent only among accessions collected from areas where the disease has been endemic for several years, whereas moderate levels of resistance can be found in accessions collected from nearly everywhere in the world.

Changes in Observed Daily Precipitation over the United States between 1950–79 and 1980–2009

2013 ◽  
Vol 14 (1) ◽  
pp. 105-121 ◽  
Author(s):  
R. W. Higgins ◽  
V. E. Kousky
Keyword(s):  
United States ◽  
Great Plains ◽  
El Niño ◽  
Daily Precipitation ◽  
El Nino ◽  
Southern Oscillation ◽  
Heavy Precipitation ◽  
The United States ◽  
Enso Cycle ◽  
Precipitation Events

Abstract Changes in observed daily precipitation over the conterminous United States between two 30-yr periods (1950–79 and 1980–2009) are examined using a 60-yr daily precipitation analysis obtained from the Climate Prediction Center (CPC) Unified Raingauge Database. Several simple measures are used to characterize the changes, including mean, frequency, intensity, and return period. Seasonality is accounted for by examining each measure for four nonoverlapping seasons. The possible role of the El Niño–Southern Oscillation (ENSO) cycle as an explanation for differences between the two periods is also examined. There have been more light (1 mm ≤ P &lt; 10 mm), moderate (10 mm ≤ P &lt; 25 mm), and heavy (P ≥ 25 mm) daily precipitation events (P) in many regions of the country during the more recent 30-yr period with some of the largest and most spatially coherent increases over the Great Plains and lower Mississippi Valley during autumn and winter. Some regions, such as portions of the Southeast and the Pacific Northwest, have seen decreases, especially during the winter. Increases in multiday heavy precipitation events have been observed in the more recent period, especially over portions of the Great Plains, Great Lakes, and Northeast. These changes are associated with changes in the mean and frequency of daily precipitation during the more recent 30-yr period. Difference patterns are strongly related to the ENSO cycle and are consistent with the stronger El Niño events during the more recent 30-yr period. Return periods for both heavy and light daily precipitation events during 1950–79 are shorter during 1980–2009 at most locations, with some notable regional exceptions.

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