NATIONAL WEATHER SUMMARY

 

SEPTEMBER 2013

 

1^st-7^th…During the first week of September, rainfall remained scarce in many areas of the nation, including the central and southern Plains and The Midwest. The dry weather was accompanied by late-season heat across the Plains and the western Midwest.

Weekly temperatures averaged at least 10F above normal in a broad area centered across the northern High Plains, and were mostly above normal west of the Mississippi River. In contrast, cooler air arrived late in the week across the lower Great Lakes region and the Northeast. Meanwhile, showers returned to the Southeast and increased in coverage and intensity across the northern High Plains and parts of the West. In the West, rain caused brought local drought relief, aided wildfire containment efforts. Elsewhere, showers were generally confined to the Northeast and areas along and near the Gulf Coast, with several locations in both regions receiving at least 2 to 4 inches of rain during the week. Heat persisted for much of the week across the nation’s midsection. McCook, NE, posted triple-digit highs from September 4-7, including daily-record readings of 106F on the 6th and 7th. Elsewhere in Nebraska, Imperial also closed the week with four consecutive triple-digit

readings, including a high of 106F on September 6. Late week heat reached as far east as the western Midwest, where Lamoni, IA, tallied a daily-record high of 100F on September 7. Heat also expanded into the lower Mississippi Valley, resulting in a daily-record high (97F on September 6) in Vicksburg, MS. Meanwhile in Colorado, Denver collected three consecutive daily-record highs (97, 97, and 95F) from September 5-7. Farther west, heat also returned to the Desert Southwest, where Phoenix, AZ, registered a daily-record high of 111F on September 6. In contrast, a late-week chill settled across the Northeast, resulting in a daily-record low (45F on September 6) in Wheeling, WV. Early in the week, heavy rain soaked parts of the Northeast. Bangor, ME, received more than 2 inches of rain on each of the first 2 days of September, totaling 4.34 inches. Elsewhere in the Northeast, daily-record totals for September 2 included 2.82 inches in Providence, RI; 2.26 inches in

Portland, ME; and 1.89 inches in Philadelphia, PA. Meanwhile, locally heavy showers affected the West, where daily-record amounts reached 1.31 inches (on September 1)

in Tonopah, NV, and 0.49 inch (on September 3) in Boise, ID. Steadier rain fell in the Northwest, boosting weekly totals to 2.34 inches in Salem, OR, and 2.21 inches in Olympia, WA. In Arizona, Kingman received at least a trace of rain, totaling 1.97 inches, on 17 consecutive days from August 22 – September 7. Prior to this year, Kingman’s longest stretch with at least a trace of rain was 12 days from July 21 – August 1, 2007. Farther east, showers near the Gulf Coast resulted in daily-record totals for September 5 in locations such as Naples, FL (2.57 inches), and McAllen, TX (0.78 inch). Late in the

week, strong thunderstorms rolled across the nation’s northern tier. On September 5 in Montana, thunderstorm wind gusts were clocked to 62 mph in Great Falls and 56 in

Lewistown. It was the highest September wind gust in Great Falls since 1971, and the highest September gust on record in Lewistown (previously, 55 mph on September 16, 1998). With a 1.64-inch total on September 6, Cut Bank, MT, experienced its second-wettest September day on record behind 1.92 inches on September 4, 1911.

Brief warmth was displaced by stormy conditions in Alaska. On September 1, King Salmon notched a daily-record high of 70F. The following day, Juneau (69F) collected a daily record high for September 2. Farther inland, McGrath received measurable rain on each day of the week, totaling 2.65 inches. McGrath also netted daily-record totals of 1.26

inches on September 1 and 0.86 inch on September 2. Similarly, Bethel’s weekly sum of 2.02 inches was aided by a daily-record total of 1.47 inches on September 1.

 

8^th-14^th…The interaction between the monsoon circulation and a cold front led to historically heavy rain and deadly flooding in parts of Colorado. Weekly rainfall totaled 6 to

18 inches or more at several locations along the eastern slopes of the central Rockies. Unusually heavy rain also soaked the remainder of the Four Corners States, as well as the central High Plains. Ironically, the High Plains rain provided much-needed drought relief. Showers also affected the Intermountain West, but little or no rain fell in the northern Rockies and the Pacific Coast States. Hot, dry weather of more than 10F above normal in

some locations. Farther east, scattered showers provided local relief to the Midwest, although weekly totals were mostly less than an inch. Light showers dotted the South. However, heavier rain was observed southern sections of Florida and Texas. Significant

rain, 2 inches or more, also fell in portions of the Northeast. Near to above normal temperatures dominated the country, except for cooler than normal weather in the rain soaked Southwest. Readings averaged at least 5F above normal across the Plains and western Corn Belt, although cooler weather arrived toward week’s end. Colorado’s rainfall led to record flooding in the South Platte River drainage basin. Along the main-stem South Platte River, a record crest was established in Kersey, CO, on September 14. The river climbed 8.79 feet above flood stage in Kersey, surpassing the May 1973 high-water mark by more than 7 feet.  Closer to the Rockies, a record crest was broken along the Cache

la Poudre River at Ft. Collins (4.06 feet above flood stage on September 13), surpassing the June 1965 standard. On September 13-14, the water level along the Big Thompson River at Drake, CO, exceeded the crest observed in that location during the historic flood of July 31, 1976. From September 9-15, official rainfall totals in Colorado included 5.26 inches in Burlington and 4.65 inches in Denver. Burlington also experienced its wettest

day on record (4.32 inches on September 12), surpassing the standard of 4.00 inches set on October 19, 1908. Similarly, Goodland, KS, received 6.15 inches during the 7-day period, assisted by a 4.11-inch deluge on September 12. It was Goodland’s second-wettest day on record, behind only 4.15 inches on June 28, 1989. Meanwhile in Wyoming, 5.79 inches pelted Cheyenne during the 7-day period ending September 15. In addition, Cheyenne’s month-to-date rainfall climbed to 6.20 inches, easily surpassing its September 1973 standard of 4.52 inches. Farther south, Guadalupe Pass, TX, netted 8.37 inches of

rain from September 9-15. During the same period, totals in New Mexico included 4.04 inches in Clayton, 3.43 inches in Roswell, and 3.14 inches in Albuquerque. With a 2.82-inch sum on September 11, Roswell endured its second-wettest September day behind 3.37 inches on September 27, 1958. In Douglas, AZ, monsoon-season rainfall climbed to 16.24 inches, shattering its record of 15.90 inches set from June 15 – September 30, 1964. In Las Vegas, NV, measurable rain fell on 5 consecutive days from September 8-12, breaking its September record of 3 days. Elsewhere, locally heavy showers dotted southern parts of Texas and Florida, as well as portions of the nation’s northern tier. Daily-record totals included 2.56 inches (on September 9) in Sault Sainte Marie, MI; 2.41 inches (on September 13) in Harlingen, TX; 1.87 inches (on September 8) in Dickinson, ND; and 1.23

inches (on September 12) in Caribou, ME. Meanwhile, record-setting warmth baked various parts of the nation. The week opened with triple-digit heat in the nation’s mid-section, resulting in daily-record highs on September 8 in locations such as McCook, NE (105F), and Topeka, KS (104F). The following day, highs soared to 100F in Lincoln, NE, and Quincy, IL, setting daily records for September 9 in both cities. Des Moines, IA (101F on September 9), experienced its latest triple-digit heat on record, replacing 101F on September 7, 1939. By mid-week, heat shifted into the East and Northwest. On

September 10-11, South Bend, IN, posted consecutive daily record highs (97 and 96F, respectively). September 11 also featured daily-record highs in Northeastern locations such as Concord, NH (95F), and Scranton, PA (95F). By week’s end, however, markedly cooler air arrived in the Midwest and Northeast. Daily-record lows for September 14 dipped to 30F in Houghton Lake, MI, and 39°F in Moline, IL. Farther west, unusual, late-season heat in the Northwest resulted in four consecutive daily-record highs (98, 97, 96, and 94F) from September 12-15 in Yakima, WA.

 

15^th-21^st…Heavy rain lingered early in the week in parts of Colorado, but mostly dry weather thereafter allowed flood recovery efforts to progress. However, a record-setting flood crest on the South Platte River coursed through northeastern Colorado and southwestern Nebraska, inundating some agricultural lowlands. Meanwhile, the tropical plume of moisture partially responsible for Colorado’s flooding shifted eastward in advance of a cold front. As a result, 1 to 3 inch rainfall totals were common along and east of a Wisconsin-to-Texas line. Even heavier rain, locally 4 inches or more, curtailed fieldwork but eased drought from central and eastern Texas to the Mississippi Delta. Wet weather also affected southern Florida. Elsewhere, generally dry weather across the Southwest and the northwestern half of the Plains contrasted with scattered showers from the Pacific Northwest to the northern Rockies. The weather change in the Southwest signaled the end of the summer rainy season, while dry weather on the northern Plains promoted winter wheat planting. Flooding rains persisted early in the week in parts of Colorado, where Colorado Springs netted a daily-record total (1.53 inches) on September 15. Colorado Springs’ 7-day (September 10-16) rainfall climbed to 3.90, while the cooperative observation site in Boulder, CO, received 16.69 inches of rain during the first half of September. Boulder’s previous wettest month had been May 1995, when 9.59 inches fell. According to emergency operations reports, Colorado’s flooding claimed seven lives, destroyed nearly 1,900 homes, and damaged more than 16,000 others. Meanwhile, month-to-date precipitation climbed to 6.22 inches in Cheyenne, WY, nearly all of which

(5.80 inches) fell from September 9-16. Prior to this year, Cheyenne’s wettest September had occurred in 1973, when 4.52 inches fell. In Nebraska, a record-setting crest on the South Platte River passed Roscoe (3.20 feet above flood stage) on September 20, and arrived 3 days later in North Platte (1.36 feet above flood stage). The Platte River at Brady, NE, crested 3.23 feet above flood stage on September 23, surpassing the May 1973 high water mark by more than a foot. As the week progressed, heavy rain began to shift eastward. North Platte, NE, collected a daily-record rainfall (2.82 inches) on September 15, followed the next day by a record-setting total of 1.44 inches in Borger, TX.

Later, South Bend, IN (3.44 inches on September 19), experienced its 11th-wettest calendar day on record. Also on September 19, daily-record totals reached 2.58 inches in Kansas City, MO, and 2.43 inches in San Angelo, TX. The following day, record-breaking amounts for September 20 reached 6.35 inches in Texarkana, AR, and 2.33 inches in Cincinnati, OH. In Pine Bluff, AR, where 4.26 inches fell on the 20th, it was the wettest September day since 1886. By September 21, additional daily-record totals included 3.80 inches in Jackson, MS; 2.79 inches in Buffalo, NY; 2.74 inches in Charlotte, NC; and 2.68 inches in Huntsville, AL. Late-week precipitation also fell in the Northwest, where daily-record amounts for September 21 reached 1.22 inches in Redding, CA, and 0.56 inch in

Roseburg, OR. An early-week chill in the East was briefly replaced by warmer weather. Daily-record lows for September 15 included 36F in Binghamton, NY, and 47F in Jackson, TN. A secondary surge of cool air resulted in daily-record lows for September 17 in locations such as Scranton, PA (36F), and Boston, MA (44F). A few days later, warmth in the Midwest produced daily-record highs for September 19 in Burlington, IA (94F), and Moline, IL (93F). The warmth had originated in the West, where daily-record highs for September 16 had soared to 111F in Phoenix, AZ, and Thermal, CA. Farther north, September 15 highs had soared to 99°F (and achieved daily-record levels) in Pendleton, OR, and Whitman Mission, WA. Late in the week, summer-like warmth returned across much of the western half of the nation. Daily-record highs for September 21 included 92F in Rapid City, SD, and 90F in Salt Lake City, UT. From August 19 – September 21, temperatures averaged more than 6°F above normal in La Crosse, WI, representing the warmest such period in that location since 1948.

 

22^nd-30^th…A cold front moved over the Rockies on Monday, bringing showers and thunderstorms to parts of the Great Basin and northern Plains, while a system of high pressure brought more fall like conditions to the East Coast. The majority of the East Coast experienced dry, cool conditions on Monday as a high pressure system drew cool air in from the north. Temperatures were in the 40s and 50s in the early morning, and rose into the 60s and 70s during the day. Southern Florida, as well as parts of Georgia and Alabama, experienced showers and thunderstorms as a pair of low pressure systems lingered in the Gulf of Mexico. Thunderstorms also lingered along the southeast coast of Texas due to a low pressure system in the western Gulf of Mexico.  As strong cold front moved slowly eastward over the Rockies and into the northern and central Plains on Monday, as thunderstorms impacted several states. The strongest of the thunderstorms moved through Colorado and Nebraska, while showers and thunderstorms also affected parts of Wyoming, Montana, and the Dakotas. The western Great Basin remained clear throughout Monday, while wet weather persisted in the Northwest. Low pressure along a stationary front brought more wet weather to the Pacific Northwest, as showers moved through western Washington and northwest Oregon. The Southwest remained under a high pressure system, as warm, dry conditions persisted throughout the day. Temperatures remained well below 100 degrees in the southern California and Arizona deserts, as Palm Springs recorded the midday high temperature of 89 degrees on Monday.

The Pacific Northwest continued to experience heavy rain on Friday as a cold front slowly approached the region, while a system of high pressure continued to bring autumn like conditions to the Northeast. A low pressure system moved closer to the Pacific Northwest earlier today as it inched its way southeastward over the eastern Pacific. Even though the system remained off of the coast, plenty of moisture was ushered into western Washington and northwest Oregon. The Southwest felt the effects of a high pressure system over northern California as warm, dry weather moved through the region. Meanwhile to the east, a cold front extended from New Mexico to Minnesota, which produced strong thunderstorms over the central U.S. Thunderstorms rolled through northern Texas, Colorado, Kansas, Nebraska, and Minnesota while light snow showers fell in the central Rockies. A system of high pressure continued to drive cool temperatures into the Northeast on Friday as humidity levels remained low. The system sat over New York, keeping temperatures in the 40s and 50s in the morning, and the 60s and 70s during the day. Parts of the Southeast, including the coasts of Florida, Georgia, and South Carolina, felt the remains of a cold front as spotty thunderstorms popped up in the area. Although the system remained well off of the coast, moisture still lingered in the region.

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