National Weather Summary

SEPTEMBER 2024

1-7: Mostly dry weather promoted summer crop maturation and harvesting, except from parts of Texas to the southern Atlantic Coast. 

a late season Western spell of hot, dry weather was nearly ideal for fieldwork, although ongoing concerns included spotty wildfires, local air-quality degradation, declining rangeland and pasture conditions, and diminishing soil moisture reserves. Weekly temperatures averaged at least 10°F above normal in scattered Northwestern locations, as well as parts of southern California. More broadly, readings averaged more than 5°F above normal in much of the Great Basin, Pacific Coast States, northern Rockies, and northern High Plains. Farther east, however, temperatures averaged 5°F or more below normal across large sections of the mid-Atlantic and Midwest, as well as eastern New Mexico and central and western Texas. Early in the week, heat lingered across the Deep South, where Tallahassee, FL, tallied consecutive daily-record highs (97 and 101°F, respectively) on September 1 and 2. Meanwhile in Alabama, record-setting highs for September 2, Labor Day, included 99°F in Mobile and Montgomery. Mobile notched another daily-record high, 98°F, on September 3. Early-month heat also affected the northern High Plains, where triple-digit, daily-record highs soared to 101°F (on September 2) in Sheridan, WY, and 101°F (on September 3) in Chadron, NE. During the mid- to late-week period, soaring Western temperatures contributed to dozens of daily-record highs, starting with Palm Springs, CA (116°F on September 4). The following day, Palm Springs recorded 121°F (not a record for the date), marking the sixth day this year in that location with 120-degree heat. Previously, the annual record in Palm Springs had been 5 such days, in 2020 and 2021. Elsewhere in southern California, Burbank tied an all-time station record with highs of 114°F on September 5 and 6, previously achieved on July 6, 2018, and September 5 and 6, 2020. From September 5-8, Long Beach, CA, posted four consecutive highs of 100°F or greater, tying a station record most recently attained on June 9-12, 1979. Record shattering heat extended beyond California’s borders, with Phoenix, AZ, logging a high of 116°F on September 5. In Oregon, September 5 featured daily-record highs of 105°F in Medford and Roseburg. With a high of 114°F on September 6, Ramona, CA, set a monthly mark originally set with readings of 112°F on September 5 and 6, 2020. Elsewhere in southern California on the 6th, daily-record highs soared to 113°F in Santa Ana; 112°F in downtown Los Angeles; and 109°F in Long Beach. Meanwhile, ongoing Northwestern heat led to consecutive daily-record highs on September 6-7 in Washington locations such as Yakima (98 and 95°F) and Ellensburg (98 and 95°F). Late in the week, autumnal air settled across the Corn Belt, lowering temperatures below 50°F. Late-week readings below 40°F were scattered across the upper Midwest, with frost and freezes noted in northeastern Minnesota and northern Wisconsin. Daily-record lows for September 7 dipped to 30°F in Hibbing, MN; 40°F in La Crosse, WI; and 42°F in Lincoln, NE. As the new month began, rain shifted southward.

8-12: In the western U.S., a cooling trend was accompanied by a few showers, which became more widespread late in the week as a cold front began to entrain moisture associated with former Eastern Pacific Tropical Storm Ileana. As the Western heat wave subsided, late-season warmth replaced previously cool conditions across the Plains, Midwest, and Northeast. Weekly temperatures averaged more than 5°F above normal from the northwestern half of the Plains into the upper Great Lakes region, with parts of northern Minnesota averaging more than 10°F above normal. In contrast, temperatures averaged at least 5°F below normal across portions of the South, East, and lower Midwest. Hot, humid weather lingered, however, across southern Florida. Long Beach, CA, achieved five consecutive triple-digit readings (103, 109, 101, 106, and 100°F) from September 5-9, setting a station record (previously, 4 days in a row from June 9-12, 1979, and three earlier occasions). On September 8, daily-record highs soared to 111°F in Woodland Hills, CA, and 110°F in Phoenix, AZ, and Riverside, CA. In fact, high temperatures in Phoenix reached 110°F or higher each day from September 4-10, boosting record-shattering tally of 110-degree readings so far this year to 61 days (previously, 55 days in 2023). On the September 9, the final day of extreme heat in California, daily-record highs included 108°F in Hanford and 105°F in downtown Los Angeles. Meanwhile, daily-record highs in Florida included 97°F (on September 9) in Punta Gorda; 96°F (on September 13) in West Palm Beach; and 95°F (on September 14) in Fort Myers. During the mid- to late-week period, heat appeared on the Plains and spread eastward. Rapid City, SD, posted a daily-record high (97°F) for September 11. Two days later in Texas, record-setting highs for September 13 included 102°F in Borger and 101°F in Amarillo. For Amarillo, it was the latest triple digit reading on record, supplanting 101°F on September 11, 1910. Both Borger (101°F) and Amarillo (100°F) logged triple-digit, daily-record highs again on September 14. Meanwhile in Michigan, Pellston (85°F) posted a daily-record high for September 14, just 6 days after Kalamazoo (40°F) collected a daily-record low. Other record-setting lows for September 8 included 38°F in New Philadelphia, OH; 41°F in Ottumwa, IA; and 42°F in Vichy-Rolla, MO. Daily-record minima for September 9 dipped to 35°F in Elkins, WV, and 40°F in Lincoln, IL. Elsewhere in West Virginia, Parkersburg opened the week with consecutive daily-record lows of 42°F on September 8-9.

15-21: Weekly temperatures 5°F or more above normal across large sections of the Plains, Midwest, and Northeast. Warmth was particularly impressive in the upper Midwest, where readings averaged at least 10 to 15°F above normal. Farther west, however, cool air settled across most areas west of the Rockies. In fact, weekly readings averaged at least 5°F below normal in parts of southern California and the Desert Southwest. As the week began, warmth broadly covered the Plains and Midwest. Muskegon, MI, tallied a trio of daily-record highs (90, 89, and 90°F) from September 14-16. Similarly, Marquette, MI, reported three consecutive daily record highs (85, 86, and 83°F) from September 15-17. Meanwhile in Texas, triple-digit, daily-record highs for September 15 included 101°F in Waco and 100°F in Austin (Camp Mabry). Soon, warmth spread into the Northeast, where Augusta, ME, notched a pair of daily-record highs (85 and 87°F, respectively) on September 16-17. During the mid- to late week period, heat intensified on the southern Plains. Borger, TX, posted a pair of 100-degree readings on September 18-19, achieving a daily record both days. Other triple-digit, daily record highs for September 19 reached 102°F in Wichita, KS; Lawton, OK; and Childress, TX. Late in the week, heat spread into the mid-South, where Fort Smith, AR, collected a daily-record high (101°F) for September 20. In Iowa, highs soared to daily-record levels on September 21, reaching 93°F in Waterloo and Mason City. As a low-pressure system moved inland across the Carolinas on September 16, daily-record rainfall totals included 2.53 inches in Lumberton, NC, and 3.84 inches in Florence, SC, with a northerly wind gust clocked to 47 mph in the latter location. On the same date, Wilmington, NC, netted 4.06 inches of rain and reported a northeasterly wind gust to 59 mph. September 16-17 rainfall totaled 7.14 inches in Beaufort, NC. Meanwhile, a Pacific disturbance delivered precipitation as far south as northern California, where Redding (0.59 inch on September 15) measured a daily-record sum.

22-28: During the second half of the week, an impressive, late-season heat wave boosted weekly temperatures at least 5 to 10°F above normal across the northern Plains and much of the West. As the week began, heat lingered across the South. On September 22-23, Chattanooga, TN, opened the week with consecutive daily-record highs (96°F both days). Heat extended as far west as the Plains, where Medicine Lodge, KS, notched a daily-record high of 102°F on September 22. Later, lingering Southern heat was mostly limited to Florida, where Tampa collected a pair of daily-record highs (95°F both days) on September 23 24. During the mid- to late-week period, summer-like heat developed across the West. From September 24-30, Phoenix, AZ, registered seven consecutive daily-record highs (108, 113, 110, 113, 117, 113, 107°F). That streak helped to boost this year’s total of 110-degree readings in Phoenix to 66 days, easily besting the 2023 annual standard of 55 days. On September 25, the high of 102°F in Sheridan, WY, marked the latest triple digit reading on record (previously, 104°F on September 7, 2022). Similarly, Colorado Springs, CO, experienced its latest-ever reading of 90°F or higher, after reaching 90°F on September 26 (previously, 91°F on September 25, 2020). Colorado Springs would break that record again on September 30, with a high of 91°F. By September 27, a long list of triple digit, daily-record highs included 113°F in Palm Springs, CA; 108°F in Tucson, AZ; 103°F in Desert Rock, NV; and 100°F in El Paso, TX. Tucson logged another daily-record high of 108°F on September 28. Farther north, late-week heat also overspread the western Corn Belt, where record-setting highs in South Dakota for September 28 rose to 95°F in Pierre and Mobridge.

 

 

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