NATIONAL STORM SUMMARY

MAY 2021

 

2-8: Active weather, primarily across the eastern half of the country, resulted in widespread rain. Precipitation was heaviest from the central and eastern Corn Belt southward to the central Gulf Coast; weekly totals of 2 to 4 inches or more were common throughout this region. Especially in areas where soils were already wet, the latest round of rain caused lowland flooding.  A broader area surrounding the core region of heavy rain—including the Atlantic Seaboard, the Rockies, and the Plains. 

 

Some of the most impressive Southern rainfall occurred on May 4, when daily-record totals topped 3 inches in Alabama locations such as Birmingham (3.59 inches) and Huntsville (3.25 inches). On the same date, daily-record totals exceeded 2 inches in Bowling Green, KY (3.11 inches); Anniston, AL (2.97 inches); and Greenville-Spartanburg, SC (2.16 inches). In addition, there were numerous reports of severe weather— high winds, large hail, and isolated tornadoes—across the Southeast from May 2-4. Periodic heavy showers extended into other regions, including the East and Midwest. Daily-record rainfall totaled 1.41 inches (on May 3) in Columbia, SC, and 1.22 inches (on May 2) in Houghton Lake, MI. As the week progressed, cold air became more deeply entrenched across the North. In Caribou, ME, precipitation on May 5-6 totaled 0.89 inch, with a trace of snow falling on the latter date. Sioux Falls, SD, recorded a trace of snow on May 8, while Ennis, MT, received 2.3 inches in a 24-hour period on May 7-8. During the same period, Ennis collected precipitation totaling 1.60 inches—the wettest 24-hour period during May in that location since 1944. Elsewhere in Montana, Glasgow netted a daily record sum of 0.74 inch on May 8, representing the wettest day in that location since September 7, 2020. From January 1 – May 7, Glasgow’s precipitation had totaled just 0.91 inch (35 percent of normal).

 

9-15: Locally heavy showers dotted the central and southern Plains, the central Gulf Coast region, and the Midwest—excluding the northern Corn Belt. Pockets of excessive rainfall (locally 4 inches or more) along and near the Gulf Coast sparked lowland flooding, especially in Louisiana and eastern Texas. 

 

A storm system crossing the Midwest and mid-Atlantic produced heavy rain. Record-setting rainfall totals for May 9 included 1.85 inches in Fort Wayne, IN; 1.61 inches in Peoria, IL; 1.43 inches in Columbus, OH; and 1.17 inches in Pittsburgh, PA. Meanwhile, a separate area of heavy showers affected the western and central Gulf Coast States, where daily-record amounts reached 3.59 inches (on May 9) in Lufkin, TX, and 4.10 inches (on May 10) in New Orleans, LA. On May 11, additional heavy rain in the Gulf Coast States resulted in daily-record totals in Shreveport, LA (3.22 inches), and Pensacola, FL (1.78 inches). During the second half of the week, a drier weather pattern developed across much of the country, although showers and thunderstorms continued to pepper the central and southern Plains. Dodge City, KS, netted a weekly sum of 1.63 inches— 0.59 and 1.04 inches on May 10-11 and 14-15, respectively. Farther north, however, January 1 – May 15 precipitation totaled less than an inch in North Dakota locations such as Jamestown (0.92 inch, or 23 percent of normal) and Hettinger (0.52 inch, or 17 percent).

 

16-22: The middle one-third of the U.S. and the Northwest received widespread precipitation, while dry weather covered the East and Southwest. Excessive rain (locally a foot or more) fell across the western half of the Gulf Coast region, sparking lowland flooding in coastal sections of Louisiana and Texas. Rainfall totaled at least 4 inches in scattered locations as far north as Missouri and eastern Kansas. Meanwhile, highly beneficial showers dotted the northern Plains, boosting topsoil moisture and aiding drought-stressed areas.  Late-season snow briefly blanketed parts of central and western Montana, along with other higher elevation sites in the West. In contrast, mostly dry weather persisted across California and the Southwest, where punishing drought persisted. 

 

Heavy rain pounded coastal Texas early in the week before slowly shifting eastward. Totals in Texasfor May 16 included 5.40 inches in Palacios and 3.43 inches in Victoria. Additional rounds of heavy rain in Victoria totaled 5.30 and 2.60 inches, respectively, on May 18 and 19, along with more than an inch on May 22 and 23. As a result, Victoria’s 8-day (May 16-23) rainfall reached 14.40 inches, while Palacios netted 13.70 inches. Exceptionally heavy rain fell on May 17 in Lake Charles, LA (12.49 inches), and Beaumont-Port Arthur, TX (9.86 inches). For Lake Charles, it was the third-wettest day on record, behind 15.79 inches on June 19, 1947, and 15.67 inches on May 16, 1980. Weekly (May 16-22) rainfall totaled 17.32 inches in Lake Charles and 14.60 inches in Beaumont-Port Arthur. May 17 wetness resulted in other dailyrecord totals in Louisiana—for example, 6.37 inches in Lafayette and 4.34 inches in New Iberia—as well as portions of the central Plains(2.86 inches in Imperial, NE) and Ohio Valley (1.53 inches in Cincinnati, OH). The following day, record-breaking rainfall amounts for May 18 reached 3.48 inches in Tyler, TX; 1.68 inches in Quincy, IL; and 1.49 inches in North Little Rock, AR. Late in the week, the precipitation shifted northward—and included the previously mentioned snow in Montana—although heavy showers lingered in the western Gulf Coast region. Daily-record totals for May 21 included 0.61 inch in Eureka, NV, and 0.32 inch in Twin Falls, ID. In Nevada, May 21-22 snowfall totaled 3.4 inches in Ely and 1.5 inches in Elko. In North Dakota, rainfall in Dickinson totaled 2.23 inches from May 20-23, boosting the year-to-date sum to 3.35 inches (78 percent of normal).

 

23-29:  The middle one-third of the U.S. and the Northwest received widespread precipitation. Also, like the previous week, mostly dry weather covered the Southwest and lower Southeast. However, a much wetter pattern developed across the eastern Corn Belt, the Ohio Valley, and the mid-Atlantic, extending into southern New England.

 

Repeated rounds of rain across the nation’s mid-section later spread to other parts of the country. On May 25, daily-record rainfall totals included 2.35 inches in Wisconsin Rapids, WI, and 1.58 inches in Abilene, TX. The following day, Texarkana, AR, received 3.65 inches, a station record for May 26. Joplin, MO, collected 3.07 inches on May 27, a record for the date. Farther north, a trace of snow fell on May 26 in International Falls, MN, and on May 27 in Bismarck, ND. Late in the week, heavy showers swept into the East and lingered across the southcentral U.S. Austin, TX, registered a daily-record sum (2.66 inches) on May 28 and tallied a monthly total of 12.27 inches (245 percent of normal). In Louisiana, May rainfall was more than a foot above normal at Lake Charles, where 20.50 inches fell, as well as Lafayette (19.17 inches) and New Iberia (17.61 inches); those totals ranged from 352 to 401 percent of normal. Heavy rain fell as far west as eastern New Mexico, where Roswell experienced its wettest 4-day period on record in May. Roswell’s 5.05-inch total from May 28-31, which included a 3.03-inch deluge on the 30th, was surpassed only by multi-day events on July 12-15, 1991 (5.83 inches), and September 30 – October 3, 2019 (5.19 inches). Farther east, daily-record rainfall totals for May 28 reached 1.98 inches in Clarksburg, WV, and 1.55 inches in Islip, NY.

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