NATIONAL STORM SUMMARY

AUGUST 2023

July 3-Aug. 5: Almost daily rains across the western and southwestern Corn Belt, extending onto the Great Plains, stabilized pasture and crop conditions but resulted in localized flooding. Weekly rainfall totals of 2 to 6 inches or more were common along an axis stretching from South Dakota to Missouri.

In Utah, Logan received 1.31 inches of rain in a 24-hour period on August 3-4, while Provo clocked a wind gust to 64 mph on August 2. Meanwhile, heavy rain in the nation’s mid-section led to dailyrecord totals for August 3 in Columbia, MO (3.77 inches), and North Platte, NE (1.50 inches). It was the wettest August day in Columbia since August 18, 2002, when 4.06 inches fell. Subsequently, downpours spread into the Southeast, where recordsetting rainfall totals for August 4 reached 2.61 inches in Alma, GA, and 2.43 inches in Jackson, TN. The Northeast also weathered some wet weather on August 4, with daily-record rainfall in New York totaling 2.00 inches in Saranac Lake and 1.61 inches—along with some hail—in Binghamton. At week’s end, additional heavy rain arrived in parts of the Midwest, where recordbreaking amounts for August 5 reached 6.14 inches in Burlington, IA; 3.29 inches in Peoria, IL; and 2.33 inches in Aberdeen, SD. For Burlington, it was the wettest August day on record (previously, 4.21 inches on August 15, 1952) and the secondwettest day in any month, behind only 6.28 inches on June 29, 1933.

6-12: On August 8-9, a devastating Hawaiian fire outbreak on Maui included the 2,170-acre Lahaina Fire, the deadliest single wildfire in modern U.S.

a mild, wet pattern across much of the central and eastern U.S. generally stabilized or improved crop conditions. There were several streaks of 2- to 4-inch rainfall totals, with locally higher amounts leading to pockets of flash flooding. Some of the heaviest rain fell in the Northeast and portions of the mid-South and interior Southeast.

multiple disturbances crossing the central and eastern U.S., showers and thunderstorms were plentiful except in the Deep South. On August 6-7, a large-scale severe weather outbreak—with hundreds of wind-damage reports and isolated tornadoes—affected much of the eastern one-third of the U.S. Fort Lauderdale, FL, netted a dailyrecord sum of 2.07 inches on August 6, followed on the 7th by dailyrecords in Parkersburg, WV (2.94 inches), and Syracuse, NY (2.45 inches). Heavy rain lingered in the waterlogged Northeast through August 8, when daily-record amounts reached 3.56 inches in Bangor, ME, and 2.58 inches in Saranac Lake, NY. By August 9, the focus for heavy rain shifted to the Midwest, where daily-record amounts included 3.64 inches in Springfield, IL, and 1.30 inches in Kansas City, MO. Some of the week’s heaviest rain fell on the 10th across the interior Southeast; Batesville, AR, received 5.99 inches, while totals topped the 2-inch mark in Crossville, TN (2.88 inches), and London, KY (2.02 inches). At week’s end, another Eastern severe weather outbreak delivered additional wind damage and isolated tornadoes, extending as far north as New York. Farther west, spotty monsoon showers led to a daily-record total (0.15 inch) for August 12 in Bishop, CA. However, Phoenix, AZ, remained dry, with measurable rain having last occurred nearly 5 months ago on March 22. The Lahaina Fire surpassed California’s Camp Fire (85 fatalities in November 2018) as the nation’s deadliest modern U.S. wildfire. In the historic West Maui community of Lahaina, most of the catastrophic loss of life and property occurred late August 8 into the early hours of the following day, when wind gusts of at least 40 to 80 mph raked parts of Maui, Honolulu, and Hawaii Counties. Additional wildfires flared around the same time elsewhere on Maui, as well as the Big Island. Official gusts on the afternoon of the 8th were clocked to 82 mph on the Big Island near Kawaihae and on Oahu at the Oahu Forest National Wildlife Refuge. Meanwhile, winds of 50 to 70 mph were observed on Maui, with a gust to 51 mph reported at the airport in Kahului. The easterly winds were largely caused by the interaction between a ridge of high pressure north of the Hawaiian Islands and Category 4 Hurricane Dora passing less than 600 miles south of Hilo on August 7 and less than 700 miles south of Honolulu on August 8.

13-19: Significant rainfall (generally 1 to 4 inches) stretched across the northern Corn Belt into the Northeast. A separate area of rain spanned the southwestern Corn Belt and the Tennessee Valley. Finally, a third area of locally heavy showers covered the southern Atlantic region.

Early in the week, separate areas of heavy rain affected the northern and southwestern Corn Belt. On August 13, daily-record rainfall totals topped the 2-inch mark in St. Joseph, MO (3.26 inches), and Kansas City, MO (2.72 inches), as well as South Dakota locations such as Sisseton (2.58 inches), Aberdeen (2.39 inches), and Watertown (2.10 inches). A day later, on the 14th, additional daily-record amounts reached 3.09 inches in Cape Girardeau, MO; 3.20 inches in Dubuque, IA; 2.69 inches in Holland, MI; and 2.08 inches in Milwaukee, WI. By August 15, Northeastern daily-record amounts totaled 1.54 inches at New York’s LaGuardia Airport and 1.13 inches in Bridgeport, CT. LaGuardia Airport collected another recordsetting total, 1.57 inches, on August 18. At midweek, heavy showers in the southern Atlantic States led to record-setting totals for August 16 in Brooksville, FL (3.48 inches), and downtown Charleston, SC (2.42 inches). Elsewhere in Florida, Tampa (2.62 inches) and Jacksonville (1.71 inches) netted record-setting totals for August 17. Late in the week, showers well in advance of Hurricane Hilary’s approach resulted in daily-record amounts for August 19 in locations such as Las Vegas, NV (0.21 inch), and Hanford, CA (0.19 inch). Notably, Phoenix, AZ, received rainfall totaling 0.02 inch on August 17, ending a 147-day dry spell that had begun on March 23. Phoenix had never experienced such a delayed “monsoon onset,” with the previous latest date of the summer’s first measurable rainfall occurring on August 14, 1995.

20-26: Late August 20, after making landfall in northwestern Mexico, former Hurricane Hilary made an historic traversal of southern California, becoming the first Eastern Pacific tropical cyclone since September 1939 to achieve an inland tropical-storm position over the U.S. In parts of southern California, August 20-21 rainfall totals of 4 to 8 inches, with isolated amounts near 12 inches, led to flash flooding and debris flows. Despite Hilary’s rapid demise over land, tropically enhanced showers spread as far north as the northern Rockies. However, just west of Hilary’s rainfall swath, numerous Northwestern wildfires in various stages of containment led to smoky conditions and poor air quality. In Washington, the Oregon and Gray Fires collectively burned about 21,000 acres of vegetation and destroyed more than 700 structures. Still, U.S. year-to-date wildfires had burned fewer than 2 million acres by late August, well below the 10-year average of 5 million acres.

Tropical Storm Harold made landfall on Padre Island, TX, on August 22 with sustained winds near 50 mph, delivering heavy rain and gusty winds, while severe thunderstorm activity in the lower Great Lakes region peaked on August 23-24, with more than a dozen tornadoes reported on the latter date from Michigan to Pennsylvania.

On August 20, Hilary single-handedly resulted in the wettest August on record in numerous southern California communities, boosting month-todate rainfall to 4.92 inches in Sandberg; 4.65 inches in Woodland Hills; 3.94 inches in Palmdale; 3.66 inches in Lancaster; 3.57 inches in Burbank; and 2.99 inches in downtown Los Angeles. Palmdale’s daily total (3.93 inches on the 20th) more than doubled its records for wettest August (1.76 inches in 1968) and wettest August day (1.55 inches on August 6, 1968). Also on the 20th, calendar-day totals topped 3 inches on an August day for the first time in locations such as Sandberg (4.62 inches), Lancaster (3.59 inches), Burbank (3.28 inches), and Palm Springs (3.18 inches). Death Valley, CA, also noted its wettest August day (2.20 inches on the 20th; previously, 1.70 inches on August 5, 2022). High-elevation event totals of 6 to 12 inches were reported in southern California locations such as Mt. San Jacinto (11.74 inches), Mt. Wilson (8.56 inches), and Mt. Laguna (7.11 inches). In southern Nevada, at elevations above 8,000 feet, storm-total rainfall reached 9.20 inches in Lee Canyon and 7.80 inches near Mt. Charleston. Meanwhile, hurricane-force wind gusts (74 mph or greater) were reported at a few high-elevation sites in southern California, including Black Mountain (84 mph) and Palomar Mountain (79 mph). Lower-elevation wind gusts on August 20 included 69 mph in Yuma, AZ, and 66 mph in Imperial, CA. Farther north, daily-record totals topped an inch on August 21 in McCall, ID (2.28 inches), and Ontario, OR (1.51 inches). Previously, McCall’s wettest calendar day had been July 28, 1984, with 2.00 inches. By August 22, the focus for heavy rain shifted to southern Texas, where Tropical Storm Harold moved ashore. Record-setting rainfall amounts for that date reached 4.74 inches in Corpus Christi and 3.98 inches in Laredo; it was the month’s first measurable rain in both locations, and the first rain in Laredo since June 8. As Harold moved ashore, easterly winds gusted to 62 mph in Corpus Christi and 52 mph in Rockport and Alice, TX. Some of Harold’s residual moisture was absorbed into the monsoon circulation; Boise, ID, measured 1.00 inch of rain (associated with Hilary) from August 20- 22 and 1.46 inches on August 26. During the mid- to late-week period, patchy rain fell in other areas, including the lower Great Lakes region. Columbus, OH, netted a daily-record total of 2.44 inches on August 24. The following day, record-setting totals for the 25th included 2.66 inches in Sidney, NE, and 1.50 inches in Worcester, MA. On August 26, Lincoln, NE, collected a daily-record sum of 2.24 inches, shortly after registering its highest readings (105°F on August 22 and 24) since July 22, 2012.

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