NATIONAL STORM SUMMARY

SEPTEMBER 2025

Aug. 31- Sep. 6: Showers associated with a series of cold fronts crossing the eastern half of the country were widespread but rarely heavy. Still, numerous totals of 2 inches or greater were observed in Texas, peninsular Florida, the southern Appalachians, the middle Missouri Valley, and the upper Great Lakes region. Meanwhile, in the West, the complex interplay between the North American monsoon circulation and moisture stripped from former eastern Pacific Hurricane Lorena led to locally heavy showers from the Desert Southwest to the southern Rockies. Isolated (Continued from front cover) showers extended northwestward into portions of California, the Great Basin, and the Northwest.

In the South, showers were occasionally heavy as cold fronts collided with lingering heat and humidity. On the last day of August, Melbourne, FL, measured a daily-record sum of 2.41 inches. Vicksburg, MS, was inundated by rainfall totaling 4.69 inches, a record for the date, on September 2, while Muscle Shoals, AL, netted 2.32 inches. For Vicksburg, it marked the wettest day since April 2, 2017, when 7.01 inches fell. On September 4, showers sweeping across the eastern U.S. resulted in daily-record amounts in Athens, GA (2.37 inches), and Allentown, PA (1.88 inches). Meanwhile, an odd Western pattern featuring a northwestward monsoon surge followed by an influx of moisture associated with former Hurricane Lorena, led to several rounds of showers. In California, daily-record amounts for September 2 included 0.30 inch in Ramona and 0.06 inch in Merced. Three days later, on the 5th, daily-record totals reached 1.51 inches in Tonopah, NV, and 0.91 inch in Winslow, AZ. Tonopah’s total was a record in that location for any day in September, previously set with 1.30 inches on September 1, 2013.

7-13: Eastern precipitation highlights were scarce, except in Florida. However, Orlando, FL, measured a daily record sum of 2.77 inches on September 7, along with a total of 6.24 inches during the 4 days ending September 9. Elsewhere in Florida, September 7-13 rainfall totaled 7.16 inches in Daytona Beach and 11.28 inches in Miami. Farther west, early-week downpours in central Kansas locally totaled 2 to 6 inches or more. Salina measured 2.86 inches on September 8, a record for the date. Meanwhile, isolated showers in the central Gulf Coast region resulted in daily-record sum (2.24 inches on September 9) in Baton Rouge, LA. Later, shower activity expanded across portions of the western and central U.S. In southeastern Arizona, Safford received a daily-record total of 0.54 inch on September 12. A day later in New Mexico, rainfall totaled 0.65 inch in Roswell and 0.52 inch in Tucumcari. Farther north, Mobridge, SD, measured 2.21 inches, a record for September 13.

14-20: Significant rain developed across the nation’s midsection, including large sections of the Plains and upper Midwest. The rain, which bypassed parts of Montana and much of Texas.

Along the middle Atlantic Coast, a non-tropical storm system interrupted an otherwise dry weather pattern. Farther west, out-of-season showers—associated with moisture stripped from the remnants of eastern Pacific Tropical Storm Mario—fell in central and southern California and parts of the Southwest.

On September 14, as the week began, severe weather—including more than a dozen tornadoes—tore across portions of the Dakotas. On that date, daily-record rainfall totals included 2.44 inches in Bismarck, ND, and 1.16 inches in Pierre, SD. Minot, ND, noted a record-setting rainfall total (1.23 inches) for September 15. Rain shifted southward by the 16th, when McCook, NE, experienced its wettest September day on record. McCook’s 5.01-inch total surpassed 4.33 inches on September 3, 2016. It was also McCook’s third-wettest day during any month, behind only 6.06 inches on May 26, 2023, and 5.13 inches on May 23, 2008. Elsewhere on September 16, daily-record totals included 1.40 inches in Broken Bow, NE, and 1.24 inches in Casper, WY. During another widespread round of showers on September 17, daily-record amounts included 2.57 inches in Pierre, SD; 2.00 inches in Borger, TX; and 1.12 inches in Dodge City, KS. Casper netted another daily record (0.82 inch), boosting its September 16-17 total to 2.06 inches. Meanwhile, mid- to late-week showers spread northward across the West. By September 18, daily-record totals in California included 0.74 inch in Hanford and 0.33 inch in Needles. Hanford noted another record, 0.28 inch, the following day. Death Valley, CA, received rainfall totaling 0.60 inch on September 18-19, contributing to flash flooding in the area. Heavy showers extended as far east as western and southern Texas, where record-setting totals included 1.95 inches (on September 19) in El Paso and 1.22 inches (on September 18) in Laredo.

21-27: Rain provided limited drought relief from the mid-South into the Northeast, although no boost in soil moisture. Still, the rain, which totaled 2 to 4 inches or more from the Ozark Plateau into southern Maine. Lighter rain fell in a much broader area of the central and eastern U.S., although the northern Plains and far upper Midwest experienced mostly dry weather.

In the West, another late-season monsoon surge delivered showers, some of which sparked flash flooding in Arizona and environs. Some of the Southwestern showers produced large hail and damaging winds. Meanwhile, in the Northwest, widely scattered showers were insufficient to provide any drought relief in the wake of a hot, dry summer.

Starting on September 22, significant rain spread across the Midwest and environs. On that date, record-setting rainfall totals included 3.28 inches in Rochester, MN; 2.77 inches in Chadron, NE; 1.70 inches in La Crosse, WI; and 1.44 inches in Carbondale, IL. For Rochester, it was the wettest September day in more than 7 years (since 3.32 inches fell on September 4, 2018), and the sixth-wettest September day on record. On September 23, another round of heavy showers led to record-setting totals in locations such as West Plains, MO (2.97 inches); Denver, CO (1.28 inches); and Imperial, NE (1.16 inches). By September 24, downpours reached drought-affected sections of the mid-South and lower Midwest; daily-record amounts reached 4.77 inches in El Dorado, AR; 3.24 inches in Poplar Bluff, MO; and 2.26 inches in Frankfort, KY. From September 22-25, Frankfort measured 4.64 inches. During the second half of the week, heavy showers shifted into parts of the southern and eastern U.S. In the latter region, record-setting amounts for September 25 included 3.36 inches in Albany, NY, and 2.65 inches in Scranton, PA. Toward week’s end, locally heavy downpours returned across the Southwest. In Arizona, Deer Valley—which had received 1.44 inches on September 18-19— recorded 1.34 inches on September 26-27. Similarly, Nogales, AZ, netted 1.28 inches on September 26, just 5 days after 1.37 inches had fallen. Elsewhere in Arizona, September 26-27 rainfall totaled 2.24 inches in Mesa and 1.85 inches in Phoenix. Much of the extreme weather in Phoenix occurred on the 26th, when rainfall of 1.64 inches led to significant flash flooding, accompanied by a peak wind gust to 56 mph. Hail up to 2 inches in diameter was reported on the 26th near Phoenix. Other peak gusts on September 26 were clocked to 65 mph in Las Vegas, NV, and 48 mph in Mesa, AZ.

Jim G. Munley, jr.
http://www.jimmunleywx.com