Montana precipitation totals5/29/2023 ![]() providing a baseline summary of climate and climate change for Montana-with a focus on changes in temperature, precipitation, and extreme events-including reviewing the fundamentals of climate change science.Climate change encompasses both increases and decreases in temperature, as well as shifts in precipitation, changing risk of certain types of severe weather events, and changes to other features of the climate system.” ![]() The US Global Change Research Program (USGCRP undated) defines climate change as follows: “Changes in average weather conditions that persist over multiple decades or longer. The largest decreases are expected to occur during summer in the central and southern parts of the state. The largest increases are expected to occur during spring in the southern part of the state. Īcross the state, precipitation is projected to increase in winter, spring, and fall precipitation is projected to decrease in summer. Increases in the number of frost-free days are expected to be greatest in the western part of the state. Increases in the number of days above 90☏ (32☌) are expected to be greatest in the eastern part of the state. The number of days in a year when daily temperature exceeds 90☏ (32☌) and the number of frost-free days are expected to increase across the state and in both emission scenarios studied. These state-level changes are larger than the average changes projected globally and nationally. By the end-of-century, Montana temperatures are projected to increase 5.6-9.8☏ (3.1-5.4☌) depending on the emission scenario. By mid century, Montana temperatures are projected to increase by approximately 4.5-6.0☏ (2.5-3.3☌) depending on the emission scenario. The state of Montana is projected to continue to warm in all geographic locations, seasons, and under all emission scenarios throughout the 21 st century. A significant increase in spring precipitation (1.3-2.0 inches ) has also occurred during this period for the eastern portion of the state. Average winter precipitation has decreased by 0.9 inches (2.3 cm), which can mostly be attributed to natural variability and an increase in El Niño events, especially in the western and central parts of the state. ĭespite no historical changes in average annual precipitation between 19, there have been changes in average seasonal precipitation over the same period. In addition, the annual number of warm days has increased by 2.0% and the annual number of cool nights has decreased by 4.6% over this period. From 1951-2010, the growing season increased by 12 days. Montana’s growing season length is increasing due to the earlier onset of spring and more extended summers we are also experiencing more warm days and fewer cool nights. Average temperatures during these seasons have risen by 3.9☏ (2.2☌) between 19. Winter and spring in Montana have experienced the most warming. The increases range between 2.0-3.0☏ (1.1-1.7☌) during this period. That means streams may be full into July, but the overall volume of water for the spring runoff season might still be closer to below normal.Annual average temperatures, including daily minimums, maximums, and averages, have risen across the state between 19. Overall, the cool wet conditions improved snowpack and pushed spring runoff into June and July.Įxperts caution, however, that the snowpack deficit earlier this spring east of the Continental Divide, combined with recent cooler weather, led to below normal stream flows. Compared to normal, that's about 70%-100% for those areas. Mountain precipitation totals were lowest in parts of central Montana, the Flathead Lake area, and the Upper Clark Fork region, where they ranged from 2-5 inches last month. Some of the largest mountain precipitation totals set 40-year records in southwest Montana and northern Wyoming. Mountain snowpack was subpar, and time was running out to make up the difference.Īpril marked the start of a major change in the weather pattern, according to the USDA’s Natural Resources Conservation Service in Bozeman. Early season expectations of a cold, snowy winter never materialized. ![]() Montana’s snowpack conditions looked bleak April 1. The cool, wet spring improved snowpack and delayed the spring runoff, but this encouraging outlook comes with a caveat. April brought the most precipitation of any month of the year to Montana. ![]()
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