NATIONAL STORM SUMMARY

 

OCTOBER 2015

4-10: Torrential rains ended early in the week in the Carolinas, but river flooding persisted for several days as excess water worked its way toward the Atlantic Coast. Only a few other areas, including western Washington, southeastern New Mexico, and parts of western Texas, received significant rain. The Southwest also noted locally heavy showers. Torrential rainfall continued in parts of South Carolina through October 5, and Southeastern showers finally ended a day later. October 4 was the wettest calendar day on record in Columbia, SC, where 6.87 inches was measured. Previously, Columbia’s wettest day had been July 9, 1959, when 5.79 inches fell. Daily record amounts for October 4 reached 5.53 inches in North Myrtle Beach, SC, and 5.19inches in Wilmington, NC. In South Carolina, October 1-6 rainfall totaled 19.81 inches at Shaw AFB; 17.32 inches in Charleston; 15.60inches in North Myrtle Beach; and 11.52 inches in Columbia. During the same 6-day period, Wilmington, NC, netted 12.85 inches. Mostly unrelated to the heavy rain, major coastal flooding (generally 4 to 7 feet above mean lower low water, or the average height of the lowest tide recorded at a station each day) was reported at several Mid-Atlantic tidal gauge sites, including Duck, NC, and Yorktown and Seawells Point, VA. In many locations, the worst tidal flooding was noted on October 4. In South Carolina, river flooding lingered for days. On October 6, the Black River at Kingstree, SC, crested 10.65 feet above flood stage, 2.88 feet above the high-water mark established on June 14, 1973. Elsewhere in South Carolina, the Edisto River near Givhans Ferry (6.06 feet above flood stage on October 8) and Lynches River at Effingham (5.73 feet above flood stage on October 6) reached their highest levels since September 1945. Similarly, the Congaree River in Columbia, SC (12.81 feet above flood stage on October 4), achieved its highest crest since April 8, 1936. Farther west, impressive rainfall also developed in the Southwest. Death Valley, CA, netted rainfall totaling 0.55 inch in a 24-hour period on October 4-5, tying an October record previously set on October 16-17, 1934, and October 3-4, 1972. Western daily record amounts for October 4 included 1.59 inches in Tonopah, NV, and 0.41 inch in Santa Barbara, CA. The following day, record setting totals for October 5 reached 0.82 inch in Newport Beach, CA; 0.66 inch in Winslow, AZ; and 0.62 inch in Las Vegas, NV. Rain eventually pushed as far east as the High Plains, where Laramie, WY, collected a daily record amount (0.87 inch) for October 6. Later, very heavy showers developed in western and southern Texas and environs; Del Rio, TX, received 2.99 inches in a 24-hour period on October 8-9, while totals approaching 10 inches were reported in and near the communities of Uvalde and Eagle Pass. By week’s end, dry weather covered much of the nation, except for showers in the Southeast and Northwest. In South Carolina, October 10 rainfall—2.00 inches, for example, in North Myrtle Beach and 1.47 inches in Columbia—aggravated flood recovery. Meanwhile, Seattle, WA, measured a daily-record rainfall (1.13 inches) for October 10.

11-15: By mid-October, however, locally heavy showers arrived in California and began to spread inland. The showers caused local flooding in southern California, the Great Basin, and parts of the Southwest, but also replenished topsoil moisture and benefited rangeland and pastures. During the second half of the week, showers arrived in California, the

Great Basin, and the Southwest. In California, record setting totals for October 15 included 0.94 inch in Palmdale; 0.65 inch in Sandberg; and 0.44 inch in Bishop. The following day in Arizona, Prescott collected a daily-record sum (0.65 inch) for October 16. The week ended with record-breaking totals for October 17 in locations such as Alturas, CA (0.63 inch);

Klamath Falls, OR (0.58 inch); and Ely, NV (0.53 inch). Ely’s October 17-18 rainfall climbed to 1.41 inches. Farther east, the season’s first widespread snow showers spread from the Great Lakes region into the Northeast. Lansing, MI, and Buffalo, NY, noted a trace of snow on October 17, while Marquette, MI, received a daily-record total of 1.2 inches.

 

18-24: A slow-moving storm that had first arrived in California on October 15 drifted eastward across the southwestern and south-central U.S., generating heavy showers. Toward week’s end, the storm lifted northward across the Plains, providing beneficial moisture for emerging winter wheat. However, rain mostly bypassed a few areas, including eastern Kansas and north-central Oklahoma. Prior to the rain’s arrival, late-season warmth was concentrated across the central U.S. The storm’s trailing cold front became infused with moisture from Patricia, the strongest hurricane on record. (Prior to reaching the southwestern coast of Mexico on October 23, Patricia’s sustained winds peaked at 200 mph). Due to the influx of tropical moisture, storm-total rainfall topped 20 inches at a few locations in northeastern Texas. Rainfall totaled 5 inches or more in a broader area covering much of eastern Texas and environs. Consequently, areas of the South that had received little rainfall in the last 4 months were suddenly deluged by flooding rains. Meanwhile, locally heavy precipitation continued to slowly expand across the West. In Montana, Livingston netted a daily record sum (0.46 inch) for October 19. The following day, October 20, Glasgow, MT, noted a daily record total of 0.67 inch. Farther south, significant rain spread across the southwestern and south-central U.S. Roswell, NM, registered a daily record amount (1.83 inches) for October 20. In northern Texas, record-setting amounts for October 21 included 2.38 inches in Borger and 1.38 inches in Dalhart. From October 22-25, rainfall totals in Texas reached 11.68 inches in Waco; 7.70 inches in College Station; 7.60 inches in Houston; 7.57 inches in Dallas-Ft. Worth; and 7.55 inches in Tyler and Austin (Bergstrom). Waco experienced its wettest 24-hour period on record, with 9.67 inches of rain falling on October 23-24. Previously, Waco’s wettest 24-hour period had occurred on December 20, 1997, when 7.98 inches fell. Waco also reported its wettest October day (7.75 inches on October 23), eclipsing the record of 5.83 inches set on October 9, 2011. Farther east, Shreveport, LA, received 6.01 inches from October 23-26. Storm-total rainfall exceeded 20 inches at a few locations in northeastern Texas, including Corsicana. From October 23-25, Corsicana was inundated by 21.05 inches of rain, most (16.35 inches) of which fell on the 23rd.

 

25-31: Heavy showers swept across the eastern one-third of the nation early in the week, then returned to the south-central and eastern U.S. toward week’s end. In parts of southern and eastern Texas, downpours atop the previous week’s deluge led to major, late-month flooding. Weekly rainfall totaled 4 inches or more in the central Gulf Coast region and parts of eastern Texas. Some of the rain fell as the week began, but another round of heavy showers arrived as the month drew to a close. However, the rain also benefited recently planted winter wheat. In contrast, little or no precipitation fell during the last week of October from California to the northern Plains, favoring autumn. Elsewhere, heavy precipitation provided some drought relief from the Pacific Northwest to the northern Rockies, while late week rain helped to ease dry conditions in east-central Kansas and environs.

 The week began with heavy rain falling in the central Gulf Coast States. In southern

Louisiana, October 24-26 totals reached 10.85 inches in Baton Rouge and 8.88 inches in

New Orleans. Prior to the 24th, neither location had received measurable rainfall in

October. October 25 was the fourth-wettest day on record in New Orleans (8.67 inches) and Baton Rouge (8.60 inches). McComb, MS, endured its second wettest day on record (8.84 inches on October 25), behind only 10.98 inches on October 4, 1964. Farther east, daily record amounts for October 26 included 5.90 inches in Pensacola, FL, and 4.81 inches in

Mobile, AL. Heavy rain also spread into the Ohio Valley, where record setting amounts for October 27 reached 2.06 inches in Evansville, IN, and 1.76 inches in Louisville, KY. By October 28, daily-record totals occurred in Eastern locations such as Mt. Pocono, PA (3.70 inches); Fort Myers, FL (2.40 inches); Dulles Airport, VA (1.97 inches); and Glens Falls, NY (1.94 inches). Precipitation ended as snow showers in parts of the Great Lakes States, resulting in a daily-record snowfall (0.2 inch) for October 28 in Rochester, MN. During the second half of the week, downpours returned to the south-central U.S. just a week after the October 22-25 deluge. For example, Austin (Bergstrom), TX, was inundated by 16.27 inches of rain on October 30-31, following 7.55 inches from October 22-25. Much (14.99 inches) of Austin’s rain fell on October 30, marking the wettest day on record in that location (previously, 8.70 inches on November 23, 1974). Austin’s wettest October day had been October 17, 1998, when 6.85 inches fell. Elsewhere in Texas, record setting totals for October 30 included 6.55 inches in Brownsville and 2.62 inches in Abilene. It was Brownsville’s second wettest October day behind only 9.09 inches on October 4, 1996.

The last day of October featured daily-record totals in numerous Deep South locations, including Alexandria, LA (6.10 inches); New Iberia, LA (5.27 inches); and Houston, TX (5.14 inches). In addition, several tornadoes were reported on October 30-31 from the western Gulf Coast region to the Mississippi Delta. Eventually, Texas locations such as Austin (23.82 inches) and Waco (15.19 inches) completed their wettest October and month on record. Austin’s monthly sum surpassed the 15.59-inch total of June 1981; Waco’s total exceeded the May 1965 record of 15.00 inches. Following the first wave of heavy rain, antecedent dryness prevented large-scale flooding. Nevertheless, the Trinity River in Trinidad, TX, crested 9.45 feet above flood stage on October 25, nearly 7 feet below the level (16.33 feet above flood stage) achieved on June 5, 2015. Farther downstream, the Trinity River near Oakwood, TX, crested 14.06 feet above flood stage on October 27, a little more than a foot above the level (12.85 feet above flood stage) recorded on May 30, 2015. The second round of flooding was particularly severe in the Austin area, where a record crest (20.89 feet above flood stage) was reported on Onion Creek near Driftwood, TX. The high-water mark in this location was 1.29 feet above the former record set on October 17, 1998, and 4.83 feet higher than the peak river level on May 24, 2015. Elsewhere, heavy precipitation arrived across the Pacific Northwest at week’s end. Record-setting rainfall totals for October 31 reached 2.43 inches in Troutdale, OR, and 1.30 inches in Seattle, WA.

 

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