National Climate Report - September 2013
NCEI added Alaska climate divisions to its nClimDiv dataset on Friday, March 6, 2015, coincident with the release of the February 2015 monthly monitoring report. For more information on this data, please visit the Alaska Climate Divisions FAQ.
Maps and Graphics
Temperature and Precipitation Ranks
U.S. Percentage Areas
- Climate Highlights — September
- The average temperature for the contiguous U.S. during September was 67.3°F, 2.5°F above the 20th century average — the sixth warmest September on record.
- The West, Great Plains, and much of the Gulf Coast were warmer than average during September. Seven states in the Northern Rockies and Northern Plains experienced a top 10 warm September — Idaho, Montana, Wyoming, Colorado, North Dakota, South Dakota, and Nebraska.
- In the East, near-average and below-average September temperatures were observed. No state had September temperatures that ranked among the 10 coolest on record.
- The nationally-averaged precipitation total for September was 2.99 inches, 0.51 inch above average, tying with 2004 as the 12th wettest September on record.
- Above-average precipitation was widespread across the West. Colorado, Oregon, and Washington each had their wettest September on record. Seven additional states, from New Mexico to North Dakota, had September precipitation totals that ranked among the 10 wettest on record.
- Between September 9th–16th, a cut-off low pressure system situated over the Great Basin pumped deep tropical moisture into the Colorado Front Range, resulting in record-breaking precipitation. The heaviest precipitation totals were reported in and around Boulder, Colorado, where 9.08 inches accumulated on September 12th alone, setting a new 24-hour precipitation record for the city. Boulder also broke its monthly and annual precipitation records due to the event. Streams and rivers approached and exceeded record levels with widespread flooding reported. Additional information on this flooding event can be found here:
- Below-average precipitation was observed across the Western Great Lakes, as well as the Mid-Atlantic, and coastal Southeast. Delaware and Maryland both had a top 10 dry September.
- According to the October 1st U.S. Drought Monitor report, 41.2 percent of the contiguous U.S. experienced drought conditions, down 8.9 percent since the beginning of September. Over the course of the month, the percent area of the contiguous U.S. in severe, extreme, and exceptional drought all shrank. Drought conditions improved, and in some areas quite drastically, across the Intermountain West and the Central Plains. Drought conditions remained unchanged for much of the Great Basin and California, while drought expanded and intensified across the Upper Midwest.
- The components of the U.S. Climate Extremes Index (USCEI) that examine extremes in days with precipitation and warm night time temperatures ranked as the fifth and fourth highest on record for September, respectively. When combining all components of the USCEI, the index was 10 percent above average for September. The USCEI is an index that tracks the highest and lowest 10 percent of extremes in temperature, precipitation, tropical cyclones, and drought across the contiguous United States.
- Based on NOAA's Residential Energy Demand Temperature Index (REDTI) , the contiguous U.S. temperature-related energy demand during September was 9 percent above average and the 44th highest in the 1895-2013 period of record.
- On a local basis, the number of record warm daily highs and lows (about 3,270) during September was 5.8 times greater than the number of record cool daily highs and lows (about 560).
- Climate Highlights — warm season (April – September)
- The warm season average temperature for the contiguous U.S. was 65.9°F, 1.0°F above the 20th century average and the 22nd warmest April-September on record.
- Warmth dominated the West and Northeast. California, Oregon, Washington, Idaho, Utah, and Delaware each had a top 10 warm April-September. Below-average temperatures stretched from the Upper Midwest, through the Mississippi River Valley, and into the Southeast.
- The April-September contiguous U.S. precipitation total of 18.76 inches was 2.73 inches above the 20th century average and the second wettest warm season on record. The record wettest April-September occurred in 1915, when 18.85 inches of precipitation was observed. Above-average precipitation was widespread. The Northwest, Southeast, and Northeast were particularly wet, where 15 states, from Washington State to Florida, had warm-season precipitation totals ranking among the 10 highest.
- The USCEI components that examine extremes in 1-day precipitation totals and warm night time temperatures ranked as the third and eighth highest on record for the warm season, respectively. When combining all components of the USCEI, the index was 35 percent above average for the six-month period.
- Based on REDTI, the contiguous U.S. temperature-related energy demand during April-September was 5 percent below average and the 50th lowest warm-season value in the 119-year period of record.
- Climate Highlights — year-to-date (January – September)
- The year-to-date contiguous U.S. temperature was 55.9°F, 0.8°F above the 20th century average and the 28th warmest January-September on record. Above-average temperatures for the nine-month period were observed across parts of the West, where California had its ninth warmest January-September on record. The Northeast was also warmer than average. Below-average temperatures were observed across much of the southeastern quadrant of the Lower 48.
- The year-to-date contiguous U.S. precipitation total of 24.76 inches was 2.09 inches above average and the 11th wettest January-September on record for the nation. This also marked the wettest January-September since 1998.
- Much of the contiguous U.S. had near or above-average precipitation during the first nine months of 2013. Nine states in the Southeast, Midwest, and Northern Plains had January-September precipitation totals that ranked among the 10 wettest on record. Michigan had its wettest January-September on record with 29.69 inches of precipitation, 5.68 inches above average.
- California had its driest year-to-date on record with 5.72 inches of precipitation, 9.36 inches below the 20th century average, and 1.21 inches below the previous record dry January-September of 1898.
- The USCEI components that examine extremes in the spatial extent of drought and 1-day precipitation extremes were both above average for January-September and ranked as the 10th and eighth highest on record, respectively. When combining all components of the USCEI, the index was 15 percent above average for the year-to-date period.
- Based on REDTI, the contiguous U.S. temperature-related energy demand during January-September was 6 percent below average and the 53rd lowest value on record.
Alaska Temperature and Precipitation:
- Alaska had its 36th warmest September since records began in 1918, with a temperature 0.6°F (0.3°C) above the 1971–2000 average.
- Alaska had its 11th warmest July-September since records began in 1918, with a temperature 2.7°F (0.7°C) above the 1971–2000 average.
- Alaska had its 21st warmest January-September since records began in 1918, with a temperature 1.0°F (0.6°C) above the 1971–2000 average.
- Alaska had its 18th wettest September since records began in 1918, with an anomaly that was 56.3 percent above the 1971–2000 average.
- Alaska had its 28th wettest July-September since records began in 1918, with an anomaly that was 28.5 percent above the 1971–2000 average.
- Alaska had its 19th wettest January-September since records began in 1918, with an anomaly that was 30.6 percent above the 1971–2000 average.
For additional details about recent temperatures and precipitation across the U.S., see the Regional Highlights section below and visit the . For information on local temperature and precipitation records during the month, please visit NCDC's Records page.
These regional summaries were provided by the six Regional Climate Centers and reflect conditions in their respective regions. These six regions differ spatially from the nine climatic regions of the National Climatic Data Center.
- Northeast Region: (Information provided by the Northeast Regional Climate Center)
- August's cooler-than-normal conditions carried over into September in the Northeast. With an average temperature of 60.4 degrees F (15.8 degrees C), it was 0.4 degrees below normal. Only two of the region's twelve states were warmer than normal: Maine at +1.4 degrees F (0.8 degrees C) and New Hampshire at +0.2 degrees F (0.1 degrees C). Departures for the cool states ranged from -0.1 degrees F (0.1 degrees C) in Vermont to -1.8 degrees F (1.0 degree C) in New Jersey.
- After four wetter-than-normal months in a row, the Northeast was drier than normal in September. The region's monthly precipitation total of 2.78 inches (70.61 mm) was 71 percent of normal. Maine and New Hampshire were wetter-than-normal at 126 percent of normal and 117 percent of normal, respectively. As for the ten dry states, four ranked this September among their top 20 driest. It was the fourth driest September since 1895 in Delaware (19 percent of normal) and Maryland (27 percent of normal). New Jersey, with 40 percent of normal precipitation, had its 11th driest September on record while West Virginia, at 56 percent of normal, had its 20th driest. Departures for the rest of the states ranged from 54 percent of normal in Pennsylvania to 98 percent of normal in Vermont. (Preliminary divisional precipitation values provided by John Nielsen-Gammon, Texas State Climatologist)
- At the start of the month, 4.46 percent of the Northeast, mainly central Pennsylvania, was experiencing abnormal dryness. However, by late September 9.61 percent of the region was experiencing abnormally dry conditions according to the U.S. Drought Monitor issued on September 26. In addition to Pennsylvania, abnormal dryness was introduced in parts of Maryland, New York, and Connecticut.
- Severe thunderstorms moved across the Northeast from the 1st through 3rd. Storm total rainfall of up to eight inches (203 mm) caused flash flooding while wind gusts of up to 70 mph (31 m/s) downed trees and power lines and lightning sparked multiple house fires. The storms produced hail up to two inches (5 cm) in diameter. In addition, on the 1st, a funnel cloud was spotted near Millville, Delaware, and a waterspout was reported at the Quabbin Reservoir in New Salem, Massachusetts. Another round of severe storms on the 11th and 12th brought more flash flooding, large hail, and strong winds. On the 11th, an EF-0 tornado, along with straight-lines winds, damaged trees in Piscataquis County, Maine. On the 12th, 1,000+ cloud-to-ground lightning strikes per hour occurred in parts of New Hampshire and Maine and a lightning strike near the control tower at Baltimore-Washington International Airport caused a temporary shutdown of air traffic operations. Up to 37,000 customers in Vermont, 20,000 in eastern New York, and 16,000 in New Hampshire lost power during the storms. Superstorm Sandy and strong winds were blamed for a fire in Seaside Park and Seaside Heights, New Jersey, that destroyed part of the boardwalk and more than 50 businesses on the 12th. Wiring compromised by saltwater and sand during the October 2012 storm started the fire, but winds of 30 to 40 mph (13 to 18 m/s) fanned the flames and blew embers several blocks away. A soaking rainstorm on the morning of the 13th helped firefighters extinguish lingering hot spots. Ideal weather conditions during summer and September are expected to produce a spectacular fall foliage season. New Hampshire's Division of Travel and Tourism Development projects visitors to the state between September and November will spend $1.09 billion, up 3 percent from 2012. Ideal conditions are also expected to produce a bountiful apple crop. According to the New York Apple Association, the state is expected to produce about 32 million bushels (compared to the average 29.5 million bushels) by the end of November, a modern record. Pumpkins, on the other hand, did not fare as well. Though conditions improved in time for September harvest, excess precipitation through August drowned fields, stunted plant growth, and promoted disease. As a result, prices for the gourd were higher due to the decreased supply, according to the University of Delaware Cooperative Extension.
- For more information, please go to the Northeast Regional Climate Center Home Page.
- Midwest Region: (Information provided by the Midwest Regional Climate Center)
- September temperatures were warmer than normal in the western half of the Midwest and more seasonable to the east. Monthly averages were 2 to 4 degrees F (1 to 2 C) above normal across most of Missouri, Iowa, and Minnesota. Further east monthly averaged temperatures were close to normal. Early in the month, temperatures topped 90 degrees F (32.2 C) at locations across the region and temperatures topped 100 degrees F (37.8 C) at some stations in Iowa, Illinois, Indiana, and Missouri. The first freezes of the season came to the northern reaches of the Midwest in mid-September. Northern parts of Minnesota, Wisconsin, and Michigan dropped below freezing with a few locations dropping below 28 degrees F (-2.2 C).
- September precipitation was just 25 percent to 75 percent of normal for a large part of the Midwest including most of Missouri, Illinois, Iowa, Wisconsin, and Michigan. Rainfall amounts in Ohio, Indiana, and Kentucky were generally between 75 percent and 125 percent of normal. Minnesota rainfall totals ranged from about 25 percent of normal in the south central parts to nearly double normal in west central Minnesota. The sharp transition in Minnesota from above normal to below normal showed rainfall differences of more than 3.00 inches (76 mm) over just a county or two.
- Drought conditions became slightly worse and more widespread during September. Drought areas expanded just two percent (29 to 31 percent), however severe drought increased from just under seven percent of the region to more than 11 percent.
- Harvest of corn and soybeans got underway across the Midwest in late September. The crops began the month behind the 5-year average for maturity but the warm conditions, especially in the west where maturity lagged the most, helped the crops climb closer to the 5-year average by the end of the month. The later maturing crops were vulnerable to an early freeze but most of the region remained free of sub-freezing temperatures in September allowing the crops to continue to mature and dry down for harvest.
- Severe weather reports came in on just nine days in September, just two days after the 13th of the month. There were no widespread outbreaks of severe weather. A brief tornado touched down in Illinois on the 1st but a National Weather Service storm survey team was unable to find any associated damage. On the 12th, several people observed, and photographed, waterspouts on Lake Michigan near the Illinois-Wisconsin border.
- For details on the weather and climate events of the Midwest, see the weekly summaries in the Midwest Climate Watch page.
- Southeast Region: (Information provided by the Southeast Regional Climate Center)
- Mean temperatures were near normal across much of the Southeast region in September. The greatest departures were found across parts of Alabama and northwest Florida, where monthly temperatures were as much as 2 degrees F (1.1 degrees C) above normal. In contrast, monthly temperatures were between 1 and 2 degrees F (0.5 and 1.1 degrees C) below normal across eastern portions of Virginia, North Carolina, and South Florida. Monthly temperatures were above normal across Puerto Rico and near normal across the U.S. Virgin Islands. Aguirre, PR reached 99 degrees F (37.2 degrees C) on the 2nd of the month, which was the highest temperature recorded on the island in eight years. San Juan, PR recorded a maximum temperature of 96 degrees F (35.5 degrees C) on the 29th of the month, which fell just 1 degree F (0.6 degrees C) short of the warmest temperature recorded on any September day at that station in a record extending back to 1898. The warmest weather of the month occurred during the first two weeks as temperatures exceeded 90 degrees F (32 degrees C) across a large portion of the Southeast. The coldest weather occurred in the days following the passage of a cold front during the final week of the month. Temperatures dropped into the 30s (-1.1 to 3.8 degrees C) across the higher elevations of the Southern Appalachians and into the 40s (4.4 to 9.4 degrees C) as far south as central Georgia and Alabama.
- After several months of exceptionally wet weather, much of the Southeast recorded below normal precipitation in September. The driest locations were found across the eastern half of Virginia, southeastern North Carolina, and northwestern South Carolina, where monthly precipitation deficits of 3 to 5 inches (76 to 127 mm) were recorded. Wilmington, NC recorded just 1.04 inches (26 mm) of precipitation, making it the 5th driest September in a record extending back to 1871. In contrast, the wettest locations across the Southeast were found across southwestern Florida, where monthly totals were between 4 and 8 inches (102 and 203 mm) above normal. Much of this rain fell during the last week of the month as a stalled frontal boundary interacted with a plume of Atlantic moisture. Daily rainfall totals of 4 to 7 inches (102 to 178 mm) were reported along much of the western Florida Peninsula, resulting in localized flooding. Rainfall was also above normal across parts of Puerto Rico and the U.S. Virgin Islands due in large part to moisture connected with Tropical Storm Gabrielle, which dropped as much as 6 inches (152 mm) of rain across southeastern Puerto Rico and over 8 inches (203 mm) across parts of St. Thomas on the 4th and 5th of the month. Charlotte Amalie Airport on the island of St. Thomas recorded 5.37 inches (136 mm) on the 5th, making it the 8th highest total for any calendar day in a record extending back to 1953.
- There were 119 preliminary reports of severe weather across the Southeast in September, with at least one report on about half of the days. Three tornadoes were confirmed across the region. On the 16th of the month, an EF0 tornado was reported in Palm Beach County, FL, resulting in minor damage to trees and property. Strong storms ahead of an approaching cold front spawned two tornadoes in North Carolina, an EF1 in Stokes County on the 21st and an EF0 near Holden Beach in Brunswick County on the 23rd of the month. The tornado in Stokes County uprooted several trees and damaged at least three structures, including a barn which was completely destroyed. The tornado near Holden Beach also uprooted and snapped several trees and power lines, and caused minor damage to a few homes.
- The relatively drier weather in September resulted in a re-emergence of abnormally dry conditions (D0) on the U.S. Drought Monitor across extreme west-central Alabama and extreme northern Virginia (near Washington D.C.). The dry weather was a welcome sign to many farmers across the region, as they were able to complete their harvest, begin planting fall crops, and prepare fields for winter planting. However, most agricultural activities and overall crop development were running several weeks behind schedule due to the cool, wet summer. Forage was in generally poor condition, particularly across Florida, due to the excess moisture and the lack of nutritional quality was restricting the development of livestock. Citrus crops, on the other hand, were thriving across South Florida in part due to the excess moisture over the past several months.
- For more information, please go to the Southeast Regional Climate Center Home Page.
- High Plains Region: (Information provided by the High Plains Regional Climate Center)
- September 2013 was quite warm across the High Plains Region - even a mid-month cool down could not drop the monthly average temperatures to below normal. A large area of the Region stretching from central Kansas and eastern Colorado to the Canadian border had average temperatures of at least 4.0 degrees F (2.2 degrees C) above normal. Even some pockets of Nebraska, Wyoming, and the Dakotas had temperature departures of up to 8.0 degrees F (4.4 degrees C) above normal. As a result, many locations ranked in the top 10 warmest Septembers on record. For instance, Huron, South Dakota had its 3rd warmest September on record with an average temperature of 68.4 degrees F (20.2 degrees C), which was 6.7 degrees F (3.7 degrees C) above normal (period of record 1881-2013). Extremely warm temperatures at the beginning of the month also led to many daily records. The highest temperature in the Region occurred in Beaver City, Nebraska on the 8th with 109 degrees F (42.8 degrees C). Not only did this set a new record for the day, this also tied with September 3, 1947 for the highest September tem-perature on record (period of record 1893-2013). Another extreme location was Denver, Colorado which tied for its highest September temperature of 97 degrees F (36.1 degrees C) on both the 5th and the 6th (period of record 1872-2013).
- Precipitation was the big story this month in the High Plains Region. Copious amounts of rain fell across Colorado, Wyoming, much of North Dakota, northern South Dakota, western Kansas, and the panhandle of Nebraska where precipitation totals of 200-400 percent of normal were common. Most of the precipitation fell in one week — the 9th through the 15th. Precipitation totals even topped 400 percent of normal in north-central and northeastern Colorado, southern Wyoming, northwestern Kansas, and an area along the southwestern border of the Dakotas. While the destructive flooding in Colorado grabbed the headlines, other areas in the Region received large amounts of precipitation and flash flooding as well. Some areas actually did miss out on the rains and received less than 50 percent of normal precipitation. Those areas included southeastern Kansas, northeastern Nebraska, and parts of central and southeastern South Dakota.
- Numerous records were set this month — daily, monthly, and even some all-time records were just completely smashed. One example is from Goodland, Kansas which received 6.49 inches (165 mm) of precipitation. This new record for September was 5.27 inches (134 mm) above normal, or a whopping 532 percent of normal precipitation! The old record of 5.39 inches (137 mm) was set back in 1973 (period of record 1895-2013). 4.11 inches (104 mm) of the monthly total fell on the 12th and just obliterated the old daily record of 0.85 inches (22 mm). The rainfall on that day went down as the second highest one-day rainfall total on record and came just short of the record 4.15 inches (105 mm) that fell on June 28, 1989. Interestingly, even with the extremely heavy rainfall, Goodland was still running a precipitation deficit for the year. Wyoming had its share of records as well. Cheyenne, Wyoming set a new record for wettest September with 6.95 inches (177 mm) of precipitation which was 470 percent of normal. The old record of 4.52 inches (115 mm) also occurred in 1973 (period of record 1871-2013). Just like Colorado, the bulk of the precipitation (5.79 inches / 147 mm) fell during the week of the 9th-15th. The heaviest day for Cheyenne was the 13th with 1.37 inches (35 mm) and this snuck past the old record of 1.06 inches (27 mm) received in 1996.
- September was an eventful month for the state of Colorado. The month started off with exceptionally warm and dry weather with record to near-record heat occurring across northeast and north-central portions of the state. Conditions changed quickly and dramatically, however. An upper level low, positioned over the desert southwest, pulled subtropical moisture northward across the state from the 9th through the 15th. Early during the event, moderate rainfall amounts were reported for many locations along the Front Range with a few areas, such as Denver and Boulder, receiving heavy rainfall of up to 2.0 inches (51 mm). On the 11th, moderate rainfall continued to fall, however showers began to intensify and become more widespread by the evening. A narrow band of very heavy rain formed just north of Denver and moved westward toward the foothills. Rainfall rates of 2.0 inches per hour (51 mm/hour) were reported out of the heaviest showers and as the evening progressed, flash flooding became widespread. The heavy rain continued into the morning hours of the 12th with torrential rain developing in other areas, such as Aurora. Rainfall totals the morning of the 12th were staggering with many locations receiving more rainfall than they normally would during the entire month of September. Because the ground was already saturated and streams were elevated, any rain that fell on the 12th just exacerbated the flooding that was already occurring. High flows were observed on many creeks and rivers including the Big Thompson River, the Cache la Poudre River, the St. Vrain Creek, the South Boulder Creek, and the South Platte. Rainfall eased by the 13th; however the floodwaters rushed downstream out onto the plains, flooding farmland. After somewhat of a reprieve on Friday, heavy rainfall returned on Saturday and Sunday bringing more flash flooding. The multi-day rainfall event finally ended as showers tapered off late on Sunday. Even locations far away from the initial flooding were affected as the floodwaters traveled the South Platte. Communities in western Nebraska, such as Ogallala, dealt with their own round of flooding nearly a week to a week and a half after the initial flooding started in Colorado. One of the hardest hit communities was Boulder which received 9.08 inches (231 mm) of rain in one day alone, the 12th. This daily total was notable in many different ways. Not only did this amount set a new record for that day, but also for any day in Boulder's 121 year history. The old one-day precipitation record of 4.80 inches (122 mm) was set back on July 31, 1919. By the end of the month Boulder had received 18.16 inches (461 mm) of precipitation which more than tripled the old September record of 5.50 inches (140 mm) set in 1940. Ultimately, the rainfall received in Boulder was a 1 in 1000+ year event (http://hdsc.nws.noaa.gov/hdsc/pfds/). The impacts of the heavy precipitation and flooding were numerous and are still being realized. Lives were lost — many are still missing, roads and bridges were washed away, homes and business were destroyed, and some communities were cut off completely. Schools, businesses, and even the Rocky Mountain National Park closed as conditions were too dangerous. Photos indicate that the landscape has been reshaped and the incredible amount of damage that the flooding caused will take months to years to repair.
- Many changes were in store for the U.S. Drought Monitor over the past month. At the end of August, approximately 64 percent of the Region was in moderate (D1) to exceptional (D4) drought, but by the end of the month this was down to just under 50 percent. Colorado had the largest improvements and experienced a decline in drought coverage from about 94 percent to just under 65 percent. Unfortunately, much of the rain that fell caused towns, roads, bridges, and farmland to become inundated in one of the worst floods in at least 35 years. All D4 conditions were eliminated in Nebraska and Kansas and only a small portion remained in eastern Colorado. Moderate to heavy rain also fell in southern Wyoming, western Nebraska, and western Kansas, improving drought conditions there as well. One of the only areas in the Region that showed declines was northeastern South Dakota where recent heat and dryness led to a one category degradation to severe drought (D2) there. According to the U.S. Seasonal Drought Outlook released September 19th, current drought conditions should persist everywhere in the High Plains Region through December 2013. No improvements were expected.
- For more information, please go to the High Plains Regional Climate Center Home Page.
- Southern Region: (Information provided by the Southern Regional Climate Center)
- The month of September proved to be a warmer than normal month for all six states within the Southern Region. The highest departures from normal were observed in the central and west central counties of the region, with stations averaging between 3-5 degree F (1.67- 2.78) degrees C) above normal. This area includes: southern Oklahoma, north eastern Texas, northern Louisiana, and southern Arkansas. Elsewhere, temperatures averaged between 1-3 degrees F (0.56- 1.67 degrees C) above normal.
- Precipitation totals for the month of September varied spatially over the Southern Region. Much of Oklahoma and northern Arkansas reported below normal precipitation for the month, with monthly totals ranging from approximately 20 to 75 percent of normal. This was also the case in parts of north western Texas. Southern Texas, southern Arkansas, Louisiana and Mississippi experienced a wetter than normal month, with precipitation totals ranging from 100 to over 200 percent of normal. The highest anomalies were observed in the Arkansas-Texas-Louisiana border counties, and in the extreme western counties of the Texas Trans Pecos Climate Division.
- Drought conditions significantly improved over the month of September. Anomalously high precipitation in southern Texas and in Louisiana has helped reduce the amount of severe drought conditions (or worse) from 42.02 percent of the Southern Region to just 17.90 percent. There was also a significant reduction in the amount of extreme drought conditions (or worse). As of September 3, extreme drought (or worse) covered 10.78 percent of the Southern Region. By October 1, this value was reduced to just 3.16 percent. Much of this reduction occurred in the extreme southern tip of Texas and in east central Texas. In addition, the Oklahoma panhandle saw a one category improvement from extreme drought to severe drought conditions. Elsewhere, drought conditions remained relatively unchanged.
- September was a quiet month for the Southern Region with respect to severe weather occurrences. Several tornadoes were reported in Mississippi on September 20, 2013. These tornadoes were reported in the following Mississippi counties: Sunflower, Simpson, Adams, Rankin and Smith. There were no reports of injuries or fatalities. Some homes were damaged, however, most of the damaged was limited to trees and power lines.
- In Texas, extreme rainfall caused flooding in Houston, Austin, Tyler, Corpus Christi, and all the cities in between. The weekend of the 28th and 29th brought torrential rain to many parts of the state washing outs roads such as CR 477 in Lindale, and canceling events such as the Texas Red's Festival Concerts in Bryan. The biggest flooding event of the month occurred in El Paso on the 10th and 11th, when heavy rains overwhelmed the city's drainage system in many areas flooding homes and even shutting down the westbound lanes of Interstate 10. Multiple tankers were struck by lightning, causing explosions and damage to the surrounding areas, and hundreds of motorists required rescue from high water. The ample precipitation helped bring the statewide reservoir storage to around 60% of conservation storage. This is notable because, for the first time since late January, statewide reservoirs are not setting daily records for low storage but are merely tying them (Information provided by the Texas Office of State Climatology).
- For more information, please go to the Southern Regional Climate Center Home Page.
- Western Region: (Information provided by the Western Regional Climate Center)
- An active monsoon circulation as well as several storm systems brought extremely wet conditions to the West this month. Several Southwest locations experienced devastating floods. Widespread precipitation helped to alleviate some symptoms of persistent drought in the West, though significant precipitation is still needed in places to remove impacts of ongoing long-term drought. Temperatures were near normal for much of the West, with areas of much warmer than normal temperatures across the northern tier of the region.
- Intense monsoon-related precipitation took place during the first half of September in the Southwest. Most notable was the unprecedented and unusually widespread deluge on Colorado's Front Range between the 11th and 18th. A combination of moist subtropical flow from the south and an upper level low, among other features, induced prolonged intense precipitation in the area. With amounts exceeding thousand year recurrence intervals, Boulder, Colorado broke many rainfall records in its 120 years of data. On the 11th, Boulder received 9.08 in (230 mm) rainfall, exceeding the previous wettest day on record for any month by 90 percent, nearly equal to the previous wettest month. Rainfall totaled 16.48 in (419 mm) in September, shattering the record for any month, 9.59 in (244 mm) in May 1995. Year-to-date, the 31.12 in (790 mm) of rainfall at Boulder has already surpassed the annual record of 29.46 in (748 mm) also set in 1995. Elsewhere in the area, Cheyenne, Wyoming recorded 6.95 in (176 mm) precipitation for the month, crushing the previous September record of 4.52 in (114 mm) set in 1973. Records in Cheyenne began in 1915. Further south, Albuquerque, New Mexico saw 3.97 in (101 mm) of rainfall for the month, the wettest September in a 100-year record. September marks the end of the monsoon season in the Southwest (June 15-September 30). In Arizona, Tucson received 62% of normal precipitation for the season, Phoenix 110%, and Yuma 93%. In Albuquerque, New Mexico, season precipitation totaled 7.16 in (182 mm), 173% of normal.
- September is typically one of the drier months in the year in the Northwest, but in 2013 impressive rainfall throughout the region broke many records. The month began with widespread thunderstorms and locally heavy rainfall on the 4th and 5th. Corvallis, Oregon recorded a 24-hr total of 2.94 in (75 mm) on the 6th, the most precipitation received on a September day since records began in 1889. At the end of the month, a strong storm system brought both high winds and impressive rainfall to Oregon and Washington. Three day totals exceeded 9 in (229 mm) in some western Washington locations. Seattle, Washington logged its wettest September on record with a total of 6.17 in (157 mm), with 3.1 in (79 mm) of this on the last three days of the month. Bonners Ferry, Idaho recorded 4.04 in (103 mm) this month, the most in September since the records began in 1907. In Oregon, Portland received 5.62 in (143mm) for the month, easily surpassing the previous September record of 4.3 in (109 mm) set in 1986. Elsewhere in Oregon, 7.08 in (180 mm) fell in Eugene, the wettest September in a 75-year record. Further south, central and southern California received little or no precipitation, typical of September.
- The northern tier of the West saw warmer than normal temperatures this month. Quillayute, Washington averaged 61.3 F (16.3 C) for the month, the warmest September in a record that began in 1966. Great Falls, Montana recorded an average 61.9 F (16.6 C), 5.8 F (3.2 C) above normal and the 5th warmest on record. In Billings, Montana, the low temperature on September 4th only dipped to 71 F (21.7 C), the highest minimum temperature recorded in Billings in September. Reno, Nevada also saw its highest September minimum temperature of 66 F (18.9 C) on September 2nd. The previous record was 65 F (18.3 C) set on September 5, 1998. To the east, Colorado Springs, Colorado saw its 3rd warmest September in a 66-year record at 65.5 F (18.6 C).
- Dry conditions continued for much of Hawaii this month. On Oahu, Kaneohe only saw 0.05 in (1 mm), 3% of the September normal. On the Big Island, Hilo reported 3.64 in (92 mm), 36% of normal. A few stations reported above normal precipitation such as Honolulu, Oahu at 190% of normal and Lihue, Kauai at 111% of normal. Further north, Interior, South Central and northern Alaska were much wetter than normal this month. Anchorage saw 5.85 in (149 mm) precipitation this month, the 4th highest September total on record. Minor flooding was reported at Anchorage, Yakutat, and Valdez.
- September (all month): Rim Fire, Yosemite, California: This fire began August 17, cause unknown. It has since charred over 257,000 acres (104,000 hectares) and became the 3rd largest fire in California history. The fire was 92% contained by the end of the month and destroyed 11 residences.
- September 10-18: Extremely heavy rains and flooding in Colorado Front Range and New Mexico: Flooding in Colorado's Front Range resulted in eight confirmed fatalities, over 1,800 homes destroyed and over 5,500 damaged, 30 bridges swept away, and many power and natural gas outages. The governor issued a disaster declaration for 14 counties. In northern and central New Mexico, the flooding had disastrous impacts on residential and commercial structures, transportation, and infrastructure. One fatality was confirmed. Eleven New Mexico counties, including the Navajo Nation, were part of a statewide disaster declaration. Flooding occurred along the Pecos River and the Rio Grande.
- For more information, please go to the Western Regional Climate Center Home Page.
See NCDC's Monthly Records web-page for weather and climate records for the most recent month. For additional national, regional, and statewide data and graphics from 1895-present, for any period, please visit the Climate at a Glance page.
PLEASE NOTE: All of the temperature and precipitation ranks and values are based on preliminary data. The ranks will change when the final data are processed, but will not be replaced on these pages. Graphics based on final data are provided on the Temperature and Precipitation Maps page and the Climate at a Glance page as they become available.