2. Accessed March2021. www.ncdc.noaa.gov/cag. Based on the long-term Palmer Index, drought conditions in the Southwest have varied since 1895. Left imageandright imageby NickLongrich (Wikimedia Commons,Creative Commons Attribution-ShareAlike 4.0 International license, images cropped and resized). Photos of YPM IP 529539 by Jessica Utrup, 2015 (Yale Peabody Museum of Natural History/YPM,CC0 1.0 Universal/Public Domain Dedication, viaGBIF.org). Stages in the formation of a thunderstorm. Despite the monsoon rainfall this year, much of the region is still in a precipitation deficit. 2021. What happened that make TS Nora so underwhelming? The better known of these wet seasons is the summer monsoon, which lasts from about mid-June to early September. Image adapted from an image by Scenarios for Climate Assessment and Adaptation, first published in The Teacher-Friendly Guide to the Earth Science of the Southwestern US. He pointed out that ENSO does influence Pacific tropical storms, which can supply moisture to the monsoon. Introduction The overall climate of the Southwestits weather patterns over a long period of timetends to be warm and dry. Although much of the Southwest falls within the category of an arid zone, using a single label to describe the Southwest's climate would belie its diversity. A large, low-latitude desert formed along Pangaea's western margin, generating extensive dune deposits. Here, oases with large trees, large colonies of burrowing animals, and reptile trackways punctuated the otherwise dry and sandy landscape. There was likely little or no glacial ice anywhere on Earth, and temperatures were highest in lower latitudes. Summer temperatures on the South Rim, at 7000 feet (2134 meters), are especially pleasant from 50 to about 85 F (10s to 20s C). PRI is a registered 501(c)(3) nonprofit organization. Glaciation in the Southern Hemisphere occurred during the late Devonian, while the supercontinent Gondwana was located over the South Pole, and intensified during the early Carboniferous. Today nearly all the glaciers in the Southwest are gone, and the climate is in an arid state. Petrified log at Escalante Petrified Forest State Park, Jurassic Morrison Formation, Garfield County, Utah. Snowfall will be below normal in most areas that normally receive snow, with the snowiest periods in early to mid-January and early February. During much of the year, the prevailing wind over northwestern Mexico, Arizona, and New Mexico is westerly (blowing from the west) and dry. Photo by James St. John (flickr, Creative Commons Attribution 2.0 Generic license, image resized). Facebook Tweet In fact, this monsoon may turn out to be the wettest on record for some places! A .gov website belongs to an official government organization in the United States. Zack also mentioned our good friend El Nio! 4. In winter, rising temperatures have increased the number of frost-free days. Convective mixing stops because the vertical column of air has turned over so that the cool air is at the bottom and the warm air is at the top. Droughts also contribute to increased pest outbreaks and wildfires, both of which damage local economies, and they reduce the amount of water available for generating electricityfor example, at the Hoover Dam.1. A shift in plant type to those better adapted to drier conditions further suggests a change in climate during the Permian. Well those extra storms probably just go somewhere else because of the change in wind pattern that the El Nino brings, eh? The southwestern desert is hot, with winter daytime temperatures in the lower 60s and average summer daytime temperatures between 105 and 115F. Pleistocene Lake Bonneville. Shallow seas invaded the continent, ultimately covering the whole area until the late Carboniferous. Before the Isthmus closed, the Atlantic and Pacific oceans were connected. Check out Toms recent post on the drought in Arizona to understand more about how drought works in this region. Average annual preciptiation for the southwestern U.S. Southwestern states are stepping up their use and production of renewable energy. The rainfall generally has a strong diurnal cycle, meaning a daily pattern of mostly dry mornings, storms developing through the day, and most rainfall occurring in the afternoon and evening. The monsoon starts to develop in Mexico in June, and moves into the U.S. Southwest in July. Note that the southwestern region of the U.S. is covered by a shallow sea. In winter, daily temperatures in the southwest are cooler with highs in the 50s and 60s F, and lows in . Northwestern Mexico receives upwards of 75% of its average annual precipitation from it, and Arizona and New Mexico more than 50%, during JulySeptember. An official website of the United States government. By comparison, the average high and low temperatures for the entire United States are 17C (63F) and 5C (41F), respectively. Hey! The first letter of each zone in the key indicates its major classification. On the other hand, there is not much agreement among projections for future change in the monsoon, except for regarding the timingmost projections suggest that, under continued climate change, the monsoon will start later in the summer and end later in the fall than it currently does (3). Sand dunes started to become widespread. Funnel clouds (developing tornadoes) over El Paso County, Colorado, March 29, 2019. This feature focuses on six states that are commonly thought of as southwestern and characterized at least in part by arid landscapes and scarce water supplies: Arizona, California, Colorado, Nevada, New Mexico, and Utah. According to the photographer, the largest stones were 1.5 to 2.5 centimeters (0.6 to 1 inch) size. Precipitation has become more variable from year to year, and heavy downpours across the U.S. have increased in the last 20 years. In the Southwest, climate change may impact a variety of resources, including water availability in the form of snowpack and spring streamflow, the distribution and composition of plant communities, and fire regimes. Photo credits: 1916 photo from USGS (public domain), 2013 photo by daveynin (flickr,Creative Commons Attribution 2.0 Generic license, image resized). Agua Caliente solar farm, Maricopa County, Arizona. Images by Lauren Dauphin, NASA Earth Observatory (used following NASA's image use policy). Please click here to see any active alerts. Lake Mead, the lake created by the Hoover Dam, at two points in time about 21 years apart. The Southwest Region climate in the United States is often associated with extremes. Is the tropical storm season done for this part of the country? Climate change is affecting the Southwest's water resources, terrestrial ecosystems, coastal and marine environments, agriculture, and energy supply. Right:Sabalites, a palm leaf. Since 800,000 years ago, an equilibrium has been reached between warming and cooling, with the ice caps growing and retreating primarily due to the influence of astronomical forces (i.e., the combined gravitational effects of the Earth, Sun, moon, and planets). The American Southwest might evoke images of a hot, dry landscapea land of rock, canyons, and deserts baked by the sun. Shiprock, a volcanic monadnock in San Juan County, New Mexico, rises roughly 483 meters (1583 feet) above the desert plain. People in the Southwest are particularly dependent on surface water supplies like Lake Mead, which are vulnerable to evaporation. February 2023 ENSO update: the ENSO Blog investigates, part 3, How the pattern of trends across the tropical Pacific Ocean is critical for understanding the future climate, January 2023 La Nia update, and the ENSO Blog investigates, part 2, Albuquerque, NM National Weather Service office, ENSO does influence Pacific tropical storms, Tucson recorded its wettest month ever this July, Monsoon causes deadly flash flood in Arizona, Images of CO2 emissions and transport from the Vulcan project, TreeFlow: Streamflow Reconstructions from Tree Rings. Precipitation, while sparse, peaks in the summer during the monsoonal storms, and again in the winter from storms originating in the Pacific Ocean. Wildfire risk map for the United States. Loess is often, though not exclusively, associated with dry areas around glaciers. Photo by James St. John (flickr,Creative Commons Attribution 2.0 Generic license, image cropped and resized). Fossil mammals adapted to colder temperatures are found in the Pleistocene of Colorado. Drier conditions occurred through the 1920s/1930s, again in the 1950s, and since 1990, when the Southwest has seen some of the most persistent droughts on record (see Figure 3). This circulation brings thunderstorms and rainfall to the monsoon region, providing much of their annual total precipitation. Figure by climate.gov; data from CPC Unified data. Data from the Northeast Regional Climate Center Applied Climate Information System; 2079-2099 image shows the weighted mean of downscaled CMIP5 models in the LOCA dataset. Map modified from amap by Chiche Ojeda (Wikimedia Commons,Creative Commons Attribution-ShareAlike 4.0 International license, image cropped and modified). How would that result in less total JulyAugust rain? Good question! For example, parts of the Colorado Rockies experience cool annual temperatures and over 8 meters (25 feet) of snowfall every year, while the dry deserts in southwestern Arizona receive only about 8 centimeters (3 inches) of precipitation a year and can experience as much as a 15C (60F) degree temperature difference between night and day. The average amount of precipitation for the United States is 85.6 centimeters (33.7 inches). Brown indicates areas where experts forecast drought will persist or worsen. It smoldered beneath the ground as a dormant holdover, sleeper, or zombie fire until April, when it flared up and grew into a wildfire, an almost unprecedented occurrence in the Southwest. Figures 2 and 3 show two ways of measuring drought in the Southwest: the Drought Monitor and the Palmer Drought Severity Index. Average Annual Temperatures in the Southwestern United States. Streamflow totals for the decade of 2001-2010 in the Great Basin, Rio Grande, and Colorado River were between 5% and 37% lower than their 20. Photo by James Bo Insogna. The Southwest experiences nearly every variety of extreme weather; heat snaps and cold waves, droughts, floods, blizzards, and even tornados are all considerations for residents of the southwestern states. Natural variability, changes in irrigation practices, and other diversions of water for human use can influence certain drought-related measurements. Fossils of a cycad (Dioonopsis praespinulosa) from the Paleocene Castle Rock Flora, Colorado. (2019)Biology Letters15: 20190114(Creative Commons Attribution 4.0 International license, images cropped, reconfigured, resized, and relabeled). Deer mice are the most important rodent carriers of hantavirus in the Southwest. Modified fromFigure 11 in Kirby et al. Pangaea began to break up during the Jurassic, rifting apart into continents that would drift toward their modern-day positions. In a broad sense, the Southwests climate is mostly dry and hot, with much of the region characterized as arid. Extent of the Western Interior Seaway during the Cretaceous Period. I did a quick comparison of the average JulyAugust rainfall in the monsoon region with the Nio-3.4 index, using 70 years of records. Thick salt deposits accumulated in the northwestern Four Corners area as the seas evaporated. Photo by Kenneth Carpenter (Wikimedia Commons,Creative Commons Attribution-ShareAlike 4.0 International license, image cropped and resized). Photograph by Bill Morrow (Flickr;Creative Commons Attribution 2.0 Generic license). I listened to the Southwest Climate Podcast from CLIMAS, the Climate Assessment for the Southwest, to learn more about what affects the monsoon and its rainfall, and how Monsoon 2021 is shaping up, and reached out to the podcast co-hosts, Zack Guido and Mike Crimmins, for help with this post. Also, these favourable weather conditions usually occur more. Reconstruction created usingPaleomap(by C. Scotese) forGPlates. However, the Southwest is located between the mid-latitude and subtropical atmospheric circulation regimes, and this positioning relative to shifts in these . Moisture condenses out of the warm air as it comes into contact with cool air, forming clouds. A major contributing factor to this event was a geological change that occurred far to the south. 830 AM EST Thu Feb 16 2023. Elevation does, however, play a key role in precipitation received throughout the Southwest. Cold continental conditions dominate the higher altitudes, especially within the Rocky Mountains. 3. Photograph by Julia Manzerova (Flickr;Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Generic license; image resized). Drier days and higher temperatures will amplify evaporation, increasing the desertification of already arid areas and affecting natural ecosystems as well as increasing pressure on the water supply for agriculture and cities. 2. These increased temperatures lead to a whole host of other effects, including a decrease in snowpack, declines in river flow, drier soils from more evaporation, and the increased likelihood of drought and fires. This salt is part of the Late Carboniferous (Pennsylvanian) Paradox Formation. Right:Graph of the lake's changing level over time. While changes in the growing season can have a positive effect on some crops (such as melons and sweet potatoes), altered flowering patterns due to more frost-free days can lead to early bud bursts, damaging perennial crops such as nuts and stone fruits. In 2000-2003, the combination of severe drought and unusually high temperatures led to a significant die-off of pion pines in the Four Corners region of the Southwest. This figure uses the U.S. Drought Monitor classification system, which is described in the table in the Droughtindicator. At this time, the Southwest was still submerged. The Palmer Index is calculated from precipitation and temperature measurements at weather stations, and has been used widely for many years. Thus, each Southwestern state experiences both extreme highs and lows. Positive values represent wetter-than-average conditions, while negative values represent drier-than-average conditions. Photo by Jeffrey Beall (Wikimedia Commons,Creative Commons Attribution 4.0 International license, image resized). However, although climate change is predicted to enhance the intensity of severe weather, there is currently no way to calculate what effect climate change will have on the frequency of specific storm eventsfor example, we might see more powerful tornados, but we do not know if we will see more of them. The March-April-May (MAM) 2023 temperature outlook favors below-normal. Record high temperatures for the Southwest range from 53C (128F) in Arizona to 47C (117F) in Utah, while record low temperatures range from 56C (69F) in Utah to 40C (40F) in Arizona. . The Southwest relies on the slow melt of mountain snowpack throughout the spring and summer, when water demands are highest. There were spots that received large amounts of rain, but overall Nora was a bust. Average temperatures range from about 60 to 80 F in Paris, while in Nice and on the south coast they range from around 80 to 90 F. In recent years, heatwaves in Paris and elsewhere have brought record-breaking temperatures, sometimes exceeding 100 degrees F. Summer storm systems are common. Colorado has a generally cool and continental climate with low humidity. however, the monsoons provide life-giving moisture in a region that is always dry. Right:Reconstruction of living animals. Right (2):Crown of leaves from a mature plant. For example, the difference in annual mean temperature between Pikes Peak (4302 meters or 14,114 feet) and Las Animas (1188 meters or 3898 feet), only 145 kilometers (90 miles) to the southeast, is equivalent to that between Iceland and southern Florida! In the middle Cretaceous, oceans covered most of the Southwest, with the exception of parts of Arizona and New Mexico. By the end of the Permian, the southern ice sheets had disappeared. When you add in the sparse rain-gauge observations available in the U.S. Southwest and Mexico, it becomes even more difficult to make confident statements about the effects of the monsoon and how it can be predicted. Photo by Bob Wick, Bureau of Land Management (flickr, public domain). As the summer heat builds over North America, a region of high pressure forms over the U.S. Southwest, and the wind becomes more southerly, bringing moisture from the Pacific Ocean and the Gulf of California. By early to mid-September, wind patterns have generally reverted back to the westerly pattern, bringing an end to the monsoon. The Central American Isthmus, which today makes up most of Panama and Costa Rica, rose out of the ocean at approximately this time, formed by undersea volcanoes. Convection occurs when buoyant warm air rises (moves up) while denser cool air sinks (moves down). By the start of the Late Cretaceous, this inland sea, called the Western Interior Seaway, divided North America in two; the water was rich with mosasaurs, giant clams, and other marine life. The size and location of various lakes in which the Green River Formation sediments were deposited during the Eocene epoch. Thanks thats a big pool of warm water larger than the gulf of California and warmer than the greater Pacific Ocean. The Southwest, already the driest region in the United States, has become even drier since the mid-20th century, particularly on the hottest days . Large portions of the Southwest have experienced drought conditions since weekly Drought Monitor records began in 2000. What is the weather like in the Southwest region in summer? The American Southwest, here defined as the area between 95W and 125W and 25N and 40N, 9 covers over four million square kilometers. In the early Carboniferous (Mississippian), ice capped the South Pole and began to expand northward. Monsoon region averaged over all land gridpoints, 20N37N, 102W115W. Page snapshot:Introduction to the climate of the southwestern United States, including present, past, and future climate. These changes include the following: The seasonality and transmission frequency of insect-borne diseases and other infectious diseases prevalent in the Southwest, including plague, valley fever, and Hanta, are influenced by warming trends. Changes in atmospheric pressure during the late fall and winter can lead to an accumulation of haze. But El Nio leads to more tropical storms than average, youre saying, because youre not new here. The more than 16 million residents of the Southwest use carbon-rich fossil fuels to provide electricity for lighting, cooling, and appliances, to fuel their transportation and industry, and to make the products they use. Reconstruction created using basemap from thePALEOMAP PaleoAtlas for GPlatesand the PaleoData Plotter Program, PALEOMAP Project by C. R. Scotese (2016); map annotations by Jonathan R. Hendricks and Elizabeth J. Hermsen for PRI's[emailprotected]project (CC BY-NC-SA 4.0license). While the state is generally arid, its high western mountains experience more precipitation each year than the desert southwest and the high northeastern plateau do. Temperatures in the southwest region average greater than states up North, because there isn't as much water vapor in upper level winds to screen direct sunlight. Unless otherwise indicated, text and images on this website have Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International licenses. Burning those fossil fuels releases carbon into the atmosphere, which warms the Earth. By 2070, one can expect up to 38 more days of freeze-free weather each year. Across New Mexico, Arizona, and Utah, summer rains originate from moisture brought into the area from the Gulf of Mexico. Used under a Creative Commons license. If you live in the U.S. Southwest or northwestern Mexico, you may already be familiar with the annual climate phenomenon called the North American Monsoon, especially since rainfall in some spots has been way above average this summer. The inner canyon temperatures are extreme and hot, with a lower elevation of about 2400 feet (732 meters). Extensive Permian deposits throughout the Southwest are home to a host of fossils, including terrestrial amphibians, reptiles, and synapsids. (2015) . NOAA (National Oceanic and Atmospheric Administration). Some areas were more than 2F warmer than average (see Figure 1). Saguaro and cholla cacti in the Sonoran Desert National Monument, Arizona. Credits: Most of the text on this page comes from "Climate of the Southwestern US" by Ingrid H. H. Zabel, Judith T. Parrish, and Andrielle N. Swaby, chapter 8 in The Teacher-Friendly Guide to the Earth Science of the Southwestern US, edited by Andrielle N. Swaby, Mark D. Lucas, and Robert M. Ross (published in 2016 by the Paleontological Research Institution; currently out of print). Photo by Gregory Smith (flickr, Creative Commons Attribution-ShareAlike 2.0 Generic license, image cropped and resized). Scale bar = 5 centimeters (about 2 inches). Zack and Mike described this years monsoon for southern Arizona as generational, meaning once in a generation. While this will help with the ongoing drought in the southwest, in many regions the precipitation deficit has been building for a long time. During this time, the only exposed areas were islands in western Colorado and parts of New Mexico. As average temperatures rise and the Southwest becomes drier with a longer annual fire season (season conducive to the ignition and spread of wildfires), the number and intensity of wildfires is expected to increase. Extreme high temperatures. The Great Plains receive warm, moist air moving north from the Gulf of Mexico, and cold, dry air moving in from the Rocky Mountains and the northern U.S. Where these air masses meet, vigorous mixing causes thunderstorms. The main features that influence the areas climate are latitude, regional topography, and a low atmospheric moisture content that leads to quick evaporation. The geography and climate of the southwestern U.S. east of the Rocky Mountains (in other words, in the Great Plains region in Colorado and New Mexico) are nearly ideal for their formation of thunderstorms and tornados, especially in the summer.