September 2023 Climate Summary

September 2023 Climate Summary

Flathead Lake near Polson, Montana, Photo Courtesy of Gannon Rush

Regional Breakdown

The region grappled with warmer temperatures and spotty precipitation this month, less than ideal conditions for agricultural producers. These conditions delayed harvesting in the region, while others are planting winter wheat on dry soils. 

After another disappointing winter wheat crop this year, producers yet again started on the wrong foot.  With very dry soil conditions, planting has been difficult. Farmers are planting deeper or planting at normal depth with hopes of precipitation. 

Soybean and corn harvests have begun for many, with initial reports indicating a mixed bag of yields. Irrigated crops have reported slightly below-normal yields, while dryland yields varied widely in Kansas and Nebraska. The timing of planting this year also played a critical role in dryland corn yields, with much higher yields reported for those planted early.

Above: Departure from 1991-2020 normal temperature (top) and percent of normal precipitation (bottom) for September 2023 in the High Plains region. Maps produced by the High Plains Regional Climate Center and are available at: http://hprcc.unl.edu/maps/current

Precipitation and Water Resources

Precipitation was spotty this month, with a sharp divide in distribution in some states. Southwestern Kansas greatly benefited from the moisture, while north of I-70 in northwestern Kansas received next to nothing. Wyoming continued to be wet, with some places up to 300 percent above their normal precipitation.

After a stretch of wet condition starting in April, northwestern Kansas had the faucet turned off. Goodland only had trace amount of precipitation, establishing their driest month on record. Nearby Colby only received 0.03 inches (0.76 mm) this month to rank 2nd driest, while just a mere 60 miles to the north and south both received well over 3 inches (7.62 cm) of precipitation.

Parts of Wyoming continue to experience extreme wetness, with several locations on pace for their wettest year on record. In the western part of the state, Afton and Pinedale recorded their wettest January through September. In the central and eastern parts of the state, Shoshoni and Story also rank first respectively. Several other cities such as Casper, Cheyenne, and Rawlins are also in the top 10. 

Severe weather remained active this month, particularly in southwestern Nebraska. On the 21st, an 81 mph (130 km/h) gust occurred near McCook, and a 4-inch (10.16 cm) hailstone fell near Lexington. Hail continued to be an issue in eastern Wyoming yet again, meanwhile, Colorado had no reports of severe weather according to the Storm Prediction Center. 

Streamflow is in good to great shape across the western and northern parts of the region. Gauges are much above normal to record highs in the Dakotas and Wyoming. Eastern Kansas continues to grapple with drought, and it has been reflected in below normal streamflow reported by many gauges. Runoff for the Missouri River Basin is projected to be slightly above normal in October.

Above: Total precipitation in inches (top) and departure from normal precipitation in inches (bottom) for September 2023. These maps are produced by HPRCC and can be found on the Current Climate Summary Maps page at: http://hprcc.unl.edu/maps/current

Temperatures

Well-above-normal temperatures continued this month, with many locations in or just outside of their top 10 warmest September. Much of the region experienced 2 to 4 degrees F (1.1 to 2.2 degrees C) above normal and a very few locations reported below-normal temperatures.

Led by a scorching end to the month, numerous places ranked in the top 10 warmest category. The Dakotas were among the warmest, with Fargo, North Dakota observing their warmest month on record. The average temperature was 67 degrees F (19.4 degrees C), crushing the previous record of 65.6 degrees F (18.7 degrees C) set in 2015. Nearby Grand Forks, North Dakota as well as Sioux Falls, South Dakota ranked second, narrowly missing their respective records. Further ‘driving home the message’, every state in the region had locations reporting top 10 warmest temperatures during this month. 

Drought Conditions

Drought conditions both improved and degraded across the region, with large changes in the eastern parts of Kansas and Nebraska. Overall, abnormally dry to exceptional drought (D0-D4) was reduced by nearly 1 percent in the High Plains.

After slow improvements in central Nebraska, D4 was rapidly expanded once again. Nearly 5 percent of the state is now under D4, and it includes the highest corn-producing county in the state. Conditions did finally improve in the central and western North Dakota, after above-normal precipitation. Elsewhere in the region, both localized improvements and degradations were observed.

The U.S. Drought Monitor is produced as a joint effort of the U.S.
Department of Agriculture (USDA), National Drought Mitigation
Center, U.S. Department of Commerce, and the National Oceanic and
Atmospheric Administration (NOAA). For current Drought Monitor
information, please see: http://droughtmonitor.unl.edu/

Climate Outlooks

According to the Climate Prediction Center, an El Niño Advisory has been issued and conditions are likely to increase over the coming months. For more information, visit  https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf 

The National Weather Service’s long-range flood outlook indicates increased chances of Minor Flooding in central South Dakota. According to the National Interagency Fire Center (NIFC), fire potential will be limited across the region through January.

The seasonal temperature and precipitation outlook presented below combine the effects of long-term trends, soil moisture, and when applicable, the El Niño Southern Oscillation (ENSO). To learn more about these outlooks, please visit http://www.cpc.ncep.noaa.gov.  

Temperature

The three-month temperature outlook shows an increased chance of above-normal temperatures across the United States, except for the central states. Increased chances of above-normal temperatures are present in western Colorado and Wyoming.

Precipitation

The outlook for the next three months indicates below-normal precipitation in the Pacific Northwest and the Great Lakes, while above-normal precipitation is favored for the southeastern United States. Equal chances of above-, below-, or normal precipitation are present in the High Plains.

Drought

The U.S Seasonal Drought Outlook released on September 30th indicates drought conditions will likely improve in Kansas, Nebraska, and northeast North Dakota.

Station Summaries: By the Number

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