National Climate Report - September 2019


National Overview

September Extreme Weather/Climate Events

September Highlights

September Temperature

  • For September, the average contiguous U.S. temperature was 68.5°F, 3.7°F above the 20th century average, tying with 2015 as the second warmest September in the 125-year period of record. The warmest September on record occurred in 1998 and was 0.5°F warmer than in 2019.
  • Most of September was dominated by a trough along the West Coast, bringing more moderate temperatures to the region, and a ridge of high pressure over the eastern contiguous U.S., amplifying the warmth from the Rockies to the East Coast.
  • Above- to much-above-average September temperatures were observed across all but eight of the Lower 48 states. Record warm average monthly temperatures occurred across five states — Colorado, New Mexico, Texas, Louisiana, and Ohio — with 22 additional states having a top 10 warm month.
  • Near-average temperatures were present across the West and across northern New England.
  • Alaska had its third warmest September on record with a statewide average temperature of 44.7°F, 4.1°F above the long-term average. Record warmth was observed across the North Slope with above- to much-above-average temperatures blanketing nearly all of the state. Utqiaġvik and Cold Bay reported their warmest September on record.
  • The nationally averaged maximum temperature (daytime highs) was warmer than average during September at 80.8°F, 3.0°F above average, ranking eighth warmest in the 125-year record. Colorado, Louisiana, West Virginia, and Virginia ranked record warmest for maximum temperatures in September, while eighteen additional states across the South, Southeast, Ohio Valley, and mid-Atlantic regions had a top 10 warmest average daytime high temperature for the month.
  • The nationally averaged minimum temperature (overnight lows) during September was 56.3°F, 4.4°F above average, ranking warmest in the 125-year record. New Mexico, Texas, Oklahoma, Arkansas, Kansas, Missouri, Nebraska, Iowa, and Illinois each ranked warmest with 22 additional states' minimum temperatures ranking much-above-average. Four states ranked near average for the month while no state ranked below average for overnight low temperatures during September.
  • As of October 10, there were 5,804 daily warm high (2,661) and low (3,143) temperature records tied or broken during September. This was nearly 14 times greater than the 430 cold daily high (345) and low (85) temperature records set during the month.
  • Based on NOAA's Residential Energy Demand Temperature Index (REDTI), the contiguous U.S. temperature-related energy demand during September was 179 percent above average and ranked highest in the 125-year period of record.

September Precipitation

  • The September precipitation total for the contiguous U.S. was 2.42 inches, 0.07 inch below average, ranking in the middle third of the 125-year period of record.
  • The trough along the West Coast enhanced precipitation along the Northern Tier while the ridge of high pressure over the eastern contiguous U.S. was responsible for the very dry conditions across the South and Southeast.
  • Above- to much-above average precipitation was observed across parts of the West, the northern Plains, and portions of the Great Lakes. North Dakota had its wettest September on record.
  • Pronounced dry conditions across the South, Ohio Valley and parts of the mid-Atlantic contributed to a “flash drought” which emerged during September. Six states — Mississippi, Alabama, Georgia, Florida, Kentucky, and West Virginia — were record driest for the month with five additional states ranking among their driest 10 Septembers on record.
  • Hurricane Dorian made landfall at Hatteras, North Carolina, on September 6 as a Category 1 hurricane with maximum sustained winds estimated near 90 mph. The storm grazed the East Coast from central Florida to the Outer Banks and continued on a path which eventually made landfall in Nova Scotia with 100 mph sustained winds.
  • Tropical Storm Imelda* made landfall on September 18 near Freeport, Texas, just 45 minutes after becoming a tropical storm. Imelda weakened into a depression and, due to its slow movement, brought large amounts of heavy rainfall to southeastern Texas over the ensuing four days. Widespread areas of between two and three feet of rain fell during this time with the largest storm total of 43.39 inches reported at North Fork Taylors Bayou, Texas.
  • A significant winter storm brought widespread areas of one to two feet of snow, blizzard conditions, and bitter cold temperatures to parts of Idaho, Montana and Wyoming during September 28–30. The largest storm total reported was 52.0 inches in Babb, Montana, with several other stations reporting nearly four feet of snow. Many September snowfall and cold temperature records were broken over the course of this event.
  • Alaska’s average of 5.55 inches of precipitation in September was 0.98 inch above average and ranked in the wettest third of the 95-year record. Southwestern and southcentral Alaska received above-average precipitation, which helped to alleviate the short-term drought across the region. Below-average rainfall was present across southeast Alaska, the eastern Gulf Coast, and Kodiak Island, where drought remains intact.
  • According to the October 1 U.S. Drought Monitor report, 19 percent of the contiguous U.S. was in drought, up nine percent from the beginning of September. Drought conditions improved across the Pacific Northwest, Midwest, and Great Lakes regions, yet expanded or intensified across the Southwest, Texas, Ohio and Tennessee valleys and across the Southeast. Across Alaska, above-normal rainfall helped alleviate the short-term drought across much of the south-central region and in part of the Northeast Gulf region. Drought intensified across portions of Hawaii, but contracted in others to cover a smaller statewide footprint. Drought also contracted across southern Puerto Rico.
* Note on Tropical Storm Imelda precipitation: As is typical with very heavy rainfall events, localized bands of very heavy rain may not be completely captured by the gauge-based observing network, the basis for this analysis. This can lead to an underrepresentation of actual rainfall totals. This can be compounded by disruptions to the observers' ability to report values during or following a severe event and several of our long-term reporting stations have missing data for this event. Additionally, quality assurance routines may flag large valid values as erroneous, resulting in underestimated values. NCEI is working to ensure all valid reports are indeed validated. As a result, a more final accounting for the precipitation which fell across Texas during September will be available with the October report.

Billion-Dollar Weather and Climate Disasters

  • NCEI updated the 2019 billion-dollar weather and climate disaster list to include four additional events — Hurricane Dorian, Tropical Storm Imelda, the Southern and Eastern tornadoes/severe weather, and the Arkansas River flooding. This brings the year-to-date total to 10 weather and climate disaster events with losses exceeding $1 billion each across the U.S.
  • This is the fifth consecutive year (2015–2019) in which 10 or more billion-dollar disasters have impacted the U.S. — the first such occurrence on record. Since 1980, the years with 10 or more Billion-dollar disasters are 1998, 2008, 2011-2012, and 2015-2019.
  • Since these records began in 1980, the U.S. has sustained 254 separate weather and climate disasters where overall damages/costs reached or exceeded $1 billion (based on the CPI adjustment to 2019) per event. The total cost of these 254 events exceeds $1.7 trillion.

Year-to-Date Highlights

January-September Temperature

  • For the year-to-date, the contiguous U.S. temperature was 55.8°F, 0.8°F above the 20th century average, ranking in the warmest third of the January–September record.
  • Above- to much-above-average year-to-date temperatures were observed from the West Coast to the Gulf Coast and throughout the Southeast and much of the East Coast. Georgia and Florida had their warmest January–September on record while North Carolina tied with 2017 for warmest year-to-date on record. South Carolina, Virginia, and Alaska ranked second warmest. Near- to below-average temperatures were observed across the Great Basin, northern Rockies, central and northern Plains, as well as across the Great Lakes.
  • The contiguous U.S. average maximum (daytime) temperature during January-September was 67.4°F, 0.1°F above the 20th century average, ranking in the middle third of the 125-year record. Above- to much-above-average maximum temperatures were observed across New Mexico as well as across much of the Southeast, the mid-Atlantic, and parts of the Northeast. Below- to much-below-average maximum temperatures were observed from the northern and central Plains to the Great Lakes.
  • The contiguous U.S. January-September minimum (nighttime) temperature was 44.3°F, 1.4°F above average, and ranked in the upper third of the record. Above- to much-above-average minimum temperatures were observed from the West, to the South, and across the Southeast, Ohio Valley, Great Lakes, and most of the East Coast. Minimum temperatures averaged across Florida were record warmest for this year-to-date period while minimum temperatures for Alabama were tied for warmest with 2012 and for both Georgia and North Carolina, were tied for warmest with 2017.
  • Based on REDTI, the contiguous U.S. temperature-related energy demand during January-September was 12 percent above average and ranked in the middle third of the 125-year period of record.

January-September Precipitation

  • For the year-to-date, the national precipitation total was 27.06 inches, 3.86 inches above average, the wettest January-September on record.
  • Above- to much-above-average January–September precipitation stretched from the West Coast to New England. South Dakota had its wettest year-to-date on record, exceeding the previous record, set in 1915, by 1.67 inches. Michigan also ranked wettest on record for the January–September period. Fifteen additional states ranked among their 10 wettest such periods on record.
  • South Dakota also experienced its wettest 6-month, and 3-month time periods — the only state record wet at that many time scales.
  • Below-average precipitation fell across parts of the Northwest, South, and Southeast, where South Carolina had its 13th driest year-to-date on record.
  • The 12-month average precipitation across the contiguous U.S. for October 2018–September 2019 was 36.45 inches, 6.51 inches above average and the wettest October-September period on record. This also ranks as the fifth wettest among all 12-month periods on record.

Extremes

  • The USCEI for the year-to-date was 77 percent above average and ranked highest in the 110-year period of record. Extremes in warm maximum and minimum temperatures, wet PDSI, and days with precipitation contributed to this elevated value.
    • On the regional scale, the Upper Midwest, Southeast, Northern Rockies and Plains, and South regions ranked in the top ten for CEI values over the last 110 years, while the Ohio Valley ranked highest on record. This was due to a combination of factors including elevated extremes in warm maximum and minimum temperatures, wet PDSI values, and the number of days with precipitation. Across the Southeast, extremes in the number of days without precipitation was third highest on record and the Northern Rockies and Plains had its fifth highest extent of extremes in 1-day preciptation during September.

Regional Highlights

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 Centers for Environmental Information.

Northeast Region (Information provided by the Northeast Regional Climate Center)

  • It was the Northeast’s 19th warmest September since 1895 with an average temperature of 62.9 degrees F (17.2 degrees C), 2.2 degrees F (1.2 degrees C) above normal. Eleven of the region’s twelve states experienced a warmer-than-normal September, with five states ranking this September among their 20 warmest on record: West Virginia, second warmest; Maryland, fifth warmest; Delaware and New Jersey, eighth warmest; and Pennsylvania, ninth warmest. Average temperature departures for all states ranged from 0.3 degrees F (0.2 degrees C) below normal in Maine to 5.9 degrees F (3.3 degrees C) above normal in West Virginia. Maximum temperatures were particularly hot. For example, West Virginia’s mean maximum temperature for September was 7.9 degrees F (4.4 degrees C) above normal, its hottest on record. Meanwhile, September’s mean maximum temperature ranked as Maryland’s second hottest, Delaware’s third hottest, New Jersey’s fifth hottest, and Pennsylvania’s 13th hottest. Mean minimum temperatures for the month ranked among the 20 warmest on record for those same five states. Looking a little closer at several West Virginia sites, Beckley had its warmest September on record, while Elkins had its highest average maximum temperature for September. Both locations did not have a colder-than-normal day during the month. In addition, Elkins and Huntington each had their greatest number of September days with a high of at least 80 degrees F (27 degrees C).
  • The Northeast had its 16th driest September since recordkeeping began with 2.21 inches (56.13 mm) of precipitation, 56 percent of normal. All states were drier than normal, with seven ranking this September among their 20 driest: West Virginia, second driest; Maryland, third driest; Delaware, sixth driest; New Jersey, seventh driest; Rhode Island, 15th driest; and Connecticut and Massachusetts; 19th driest. Precipitation for all states ranged from 17 percent of normal in Maryland to 88 percent of normal of normal in Maine. As noted earlier, West Virginia was extremely dry, with September 2019 ranking as the all-time driest month on record for Beckley and as the driest September on record for Huntington. There was only one day with measurable precipitation [0.01 inches (0.25 mm)] during September in Huntington, with the site having its longest streak of days with less than or equal to 0.01 inches (0.25 mm) of precipitation at 36 days from August 28 through October 3, 2019 (the streak was ongoing at time of publication). Islip, New York, also had its driest September on record.
  • The U.S. Drought Monitor released on September 5 showed 7 percent of the Northeast was abnormally dry. These areas included parts of West Virginia, New York, Vermont, New Hampshire, Maine, and Connecticut. Below-normal precipitation, above-normal temperatures in southern areas, declining streamflow, and stressed vegetation led to the expansion of abnormal dryness and introduction of moderate drought in the region as the month progressed. By month’s end, every Northeast state had areas of dryness, with moderate drought in southern West Virginia, parts of Maryland, northern Delaware, southeastern Pennsylvania, and southwestern New Jersey. The U.S. Drought Monitor released on September 26 showed 43 percent of the region was abnormally dry and 7 percent was in a moderate drought. Impacts of dry conditions included an early start to the fire season, dry soil, stunted growth and declining quality of some crops, diminishing water supplies and streamflows, and muted colors of fall foliage.
  • On September 6 and 7, Hurricane Dorian grazed the Northeast coastline, creating high surf, rip currents, and tropical storm force winds. In parts of New England, there were some downed branches and wires. Rain totals of up to 3 inches (76 mm) were reported on Cape Cod, Nantucket, and Martha’s Vineyard in Massachusetts, as well as in eastern Maine. Coastal flooding was reported in New Jersey. September averages five tornadoes but this month there were only two: an EF-0 in New York and an EF-1 in Connecticut. Severe weather reports during the month noted some downed trees and wires, small hail, and a few instances of flooding.
  • For more information, please visit the Northeast Regional Climate Center Home Page.

Midwest Region (Information provided by the Midwest Regional Climate Center)

  • September precipitation ranged from record wet to record dry across the region. Most of the Upper Midwest received more than 150 percent of normal with some areas having more than three times normal. Meanwhile areas in the Ohio River Valley had less than 25 percent of normal in September with much of Kentucky receiving less than 10 percent of normal. Statewide, Kentucky had its driest September on record (1895-2019) with 0.23 inches (58 mm), while Iowa, Minnesota, and Wisconsin ranked among the wettest 10 percent of Septembers in their respective histories. Some local records fell on the wet side including Green Bay, Wisconsin (134-year record) which set a new September record and was less than an inch (25 mm) from setting a new January to December record by the end of September. Another record-wet location was Lancaster, Wisconsin (118-year record) which recorded 18.62 inches (473 mm) in September to break the previous September record by more than 6.49 inches (165 mm) and the record for any month by 5.99 inches (152 mm). More than two dozen stations in the Ohio River Valley recorded their driest September on record with seven Kentucky stations recording no measurable precipitation for September including Jackson, Lexington, Shepherdsville, and Danville. Other notable records for driest September included Evansville, Indiana (123-year record), Louisville, Kentucky (146-year record), and London, Kentucky (62-year record).
  • Summer-like temperatures extended into September with above-normal conditions across the Midwest. Average temperature for the region was 67.8 degrees F (19.9 C) which was 4.9 degrees F (2.7 C) above normal ranking 2019 as the second warmest September on record (1895 to 2019). Statewide temperatures set a new record in Ohio at 69.8 degrees F (21.0 C), ranked second in Missouri and Kentucky, third in Iowa and Indiana, fourth in Illinois, and among the 14 warmest in the other three Midwest states. A hundred stations set new September records for highest average temperature including several with well over 100 years of data. Among these long-term stations setting records were Akron, Ohio (129 years), Dayton, Ohio (126 years), Springfield, Missouri (132 years), St. Louis, Missouri (145 years), Indianapolis, Indiana (149 years), Lexington, Kentucky (135 years), and Louisville, Kentucky (148 years).
  • The exceptionally dry conditions in Kentucky led to moderate and severe drought in September according to the U.S. Drought Monitor. Record low precipitation and extreme heat, which increased evaporation, quickly dried out soils. More than half the state was in drought as of September 24th, with more than 90 percent of the state in drought by October 1st. Meanwhile, drought and abnormally dry conditions across the Upper Midwest decreased significantly with heavy rainfall in September. All of Minnesota, Iowa and Wisconsin were free of drought, and even abnormally dry conditions, by October 1st, while just a few counties in Michigan and Missouri were affected by drought.
  • The thunderstorm bringing heavy precipitation to the Upper Midwest often brought severe weather as well, leading to more than 500 reports of thunderstorm wind damage, hail, and tornadoes across the northern two-thirds of the Midwest. An EF-3 tornado was reported near Elk Mound, Wisconsin on September 24, destroying several structures and injuring two people. More than a dozen other small tornadoes were reported across the region during the month. Strong winds were reported across Michigan on September 11th, with gusts over 70 mph reported. The National Weather Service surveyed a storm near Grand Rapids, Michigan and found evidence of wind speeds up to 100 mph.
  • The warmer temperatures in September helped bring crops along toward maturity but likely affected grain fill, especially where it was dry. Due to the late planting that pushed into June, in eight Midwest states (excluding Kentucky) corn maturity (18 to 46 percent behind) and soybeans dropping leaves (21 to 35 percent behind) were well behind the 5-year averages on a statewide basis. The lack of freezing temperatures across much of the Midwest allowed the growing season to continue into October for most of the region.
  • For further details on the weather and climate events in the Midwest, see the weekly and monthly reports at the Midwest Climate Watch page.

Southeast Region (Information provided by the Southeast Regional Climate Center)

  • Temperatures were much above average across the Southeast and Puerto Rico for the month of September. Monthly mean temperatures were over 5 degrees F (2.5 degrees C) above normal in more than half of the 197 long-term (i.e., period of record equaling or exceeding 50 years) stations across the region. There were 45 stations that ranked or tied for 1st warmest in the Southeast region as far as mean temperatures. This includes Greenville, SC (1893-2019) at 9.5 degrees F (4.8 degrees C) above normal, Birmingham, AL (1930-2019) at 7.4 degrees F (3.7 degrees C) above normal, and Sarasota, FL (1911-2019) at 3.4 degrees F (1.7 degrees C) above normal. Daily maximum temperatures ranged from 11 degrees F (5.5 degrees C) above normal in Atlanta, GA (1878-2019; 1st warmest) to 1.7 degrees F (0.9 degrees C) below normal in Titusville, FL (1901-2019). There were only 3 of the 197 long-term stations that were below normal for daily maximum temperatures. Several stations across the region observed their highest count of September days with a maximum temperature at or above 90 degrees F (32.2 degrees C), including Montgomery, AL (1872-2019; 30 days), Pensacola, FL (1879-2019; 26 days), Atlanta, GA (1878-2019; 23 days), and Asheville, NC (1869-2019; 10 days). Minimum temperatures ranged from 9.7 degrees F (4.9 degrees C) above normal in Marion, NC (1893-2019; 2nd warmest) to 1.9 degrees F (0.9 degrees C) below normal in Niceville, FL (1937-2019). There were only 7 of the 197 long-term stations that were below normal for minimum temperatures. During the second half of the month, an unseasonably warm airmass stagnated over the region, allowing for daytime maximum temperatures to reach well above normal. On September 26th and 27th, Macon, GA (1892-2019) set daytime maximum temperature records of 102 degrees F (39 degrees C) on each day. Jacksonville, FL (1871-2019) set a daytime maximum temperature record of 97 degrees F (36 degrees C) on the 26th, which was the latest in the year it had been so hot, beating the previous record of September 21st, 1990.
  • Precipitation was well below normal across much of the Southeast region during September, with monthly totals ranging from 50 to less than 5 percent of normal. A very dry airmass was over the region for most of the month. At least 72 long-term stations observed September precipitation totals that were ranked within their five lowest values on record, including Montgomery, AL (1872-2019; 0.05 inches, 1.3 mm), Muscle Shoals, AL (1893-2019; 0.11 inches, 2.8 mm), and Charlotte, NC (1878-2019; 0.19 inches, 4.8 mm). A few long-term stations had no measurable precipitation on any day in September, including Pensacola, FL (1879-2019), Gainesville, GA (1891-2019), and Marion, AL (1950-2019). In contrast, above-normal precipitation occurred across Puerto Rico, with San Juan, PR (1898-2019) receiving 8.18 inches (207 mm) of precipitation, 2.4 inches (61 mm) above normal. Eastern North Carolina and South Carolina reported above-normal precipitation, due largely to Hurricane Dorian, where monthly totals were 100 to more than 200 percent of normal. Hurricane Dorian produced more than 9 inches (229 mm) of rainfall for Ocracoke, NC (1957-2019), Wilmington, NC (1870-2019), and more than 6 inches (152 mm) of rainfall for Charleston, SC (1938-2019).
  • There were 204 severe weather reports across the Southeast during September, which is double the median monthly frequency of 98 reports during 2000-2018. There were 36 tornadoes reported for the month, more than double the monthly average of 14. All of these tornadoes were associated with Hurricane Dorian, with 33 taking place in North Carolina and 3 in South Carolina. Most of these tornadoes were ranked EF-0 and resulted in some minor damage to buildings and downed trees. The most damaging tornado was rated an EF-2 with winds of 115 mph (51 m/s) and occurred in Emerald Isle, NC. There were 17 reports of hail, more than double the average of 7 for the month, with the largest being golf ball-sized in Salem, VA. The strongest reported winds occurred in North Carolina during Hurricane Dorian, with the Cedar Island Ferry Terminal in North Carolina reporting a wind gust of 110 mph (49 m/s), Fort Macon, NC reporting 85 mph (38 m/s), and Beaufort, NC reporting 82 mph (37 m/s). The hurricane impacted the Carolinas and Virginia as a category 1 storm, making landfall in Cape Hatteras, NC with sustained winds of 90 mph (40 m/s). Two fatalities occurred in NC due to falls off ladders in preparation for the storm. Another fatality occurred after the storm when a man clearing a fallen tree with a chainsaw sustained injuries. More than 160,000 people lost power in SC, and more than 190,000 people lost power in NC. Flooding from the storm washed out many roads, and several people on Ocracoke Island were trapped by flooding from the 4 to 7 foot storm surge, requiring rescue by boats and being airlifted off the island.
  • Drought conditions increased throughout the month of September due to extreme dryness and warmer than average temperatures for most of the region. The exceptions include the eastern Carolinas, which were impacted by Hurricane Dorian, southern Florida, and Puerto Rico. At the end of the month, a small pocket of extreme drought (D3) developed in central Alabama. Severe drought (D2) still covered small areas in Alabama, central Georgia, and areas in central South Carolina. Moderate drought (D1), ringed by an area of dry conditions (D0), expanded through western North Carolina, western South Carolina, Georgia, Virginia, northern Florida, and much of Alabama. Little change was observed in Puerto Rico, with severe drought (D2) covering the southern area, ringed by moderate drought (D1) and dry conditions (D0). Growers in Alabama continue to harvest cotton, soybean, and peanuts. However, summer pasture grasses are suffering due to the drought, and livestock farmers were concerned about resourcing hay, as they continue to feed their limited supply early and drought conditions prevent them from planting cool season annual forages. Pine trees are dying as a result of beetle damage due to the drought conditions, as well. Citrus and Marion counties in Florida showed abnormally dry conditions; however, the remaining portion of the citrus growing region remained drought-free. As a result, the citrus crops continue to do well. In Taylor County, GA, nearly all peanut and cotton harvesting stopped due to the dry conditions. Cattle are being sold or fed hay, and many water sources were drying up along with the Flint River. Vegetable producers in Grady County, GA were struggling to keep up with water demands. The sweet potato crop in North Carolina needs rain in order to finish maturing. Corn yield is incredibly low in Craven County, NC, and the hot, dry conditions are impacting grass and hay lands. Person County, NC reported that it was extremely dry and all crops are under severe stress.
  • For more information, please visit the Southeast Regional Climate Center Home Page.

High Plains Region (Information provided by the High Plains Regional Climate Center)

  • In a break from recent months, average temperatures across the High Plains region were, overall, above normal for September. Temperature departures ranged from just above normal in northern areas of the region to nearly 10.0 degrees F (5.6 degrees C) above normal in parts of Kansas. As such, many areas experienced their top 5 warmest Septembers on record, including Lincoln, Nebraska; Cheyenne, Wyoming; and Dodge City, Kansas. Precipitation, however, was not uniform across the region, with above-normal precipitation generally to the north and below-normal precipitation to the south. The Dakotas were particularly wet, with widespread precipitation totals in excess of 200 percent of normal. Consequently, several locations ranked in the top 5 wettest Septembers on record. Two locations in North Dakota, Williston and Grand Forks, experienced noteworthy records. Not only did both locations set new records for wettest September, both observed their highest single-day precipitation total for the entire month. Williston’s monthly total of 8.09 inches (205 mm) was 7.03 inches (179 mm) above normal, which is a whopping 763 percent of normal. This absolutely crushed the old record of 3.74 inches (95 mm) set back in 1959 (period of record 1894-2019). 2.32 inches (59 mm) of the monthly total fell on the 7th, which was a new record for the day and the month. Meanwhile, Grand Forks’ new monthly record of 8.14 inches (207 mm) was 397 percent of normal (1893-2019). 3.81 inches (97 mm) of this total fell on the 20th, which also set a new record for the day and the month. This is particularly impressive, given that Grand Forks’ normal for the month is 2.05 inches (52 mm).
  • Crops continued to progress through the month, but were still far behind previous years. Concerns at this time include the timing of the first freeze (some have already experienced this) and the wetness. Heavy rainfall across northern areas this month has led to muddy or inundated fields, which will be very slow to dry as the season progresses. It is possible that some areas of the region will need to wait until soils freeze in order to complete harvest.
  • In contrast to previous months, temperatures across the High Plains region were, overall, above normal this month. The greatest temperature departures occurred across Kansas, eastern Colorado, and much of Nebraska, with widespread departures of 6.0-8.0 degrees F (3.3-4.4 degrees C) above normal. Some isolated areas even had departures up to 10.0 degrees F (5.6 degrees C) above normal. This caused many locations to rank in the top 5 warmest Septembers on record, including Colorado Springs, Colorado (warmest); Dodge City, Kansas (warmest); Cheyenne, Wyoming (2nd warmest); and Lincoln, Nebraska (3rd warmest). Meanwhile, average temperatures were near normal across much of North Dakota, north-central South Dakota, and western Wyoming.
  • The month started off on the hot side across Colorado and Wyoming. Record-breaking maximum temperatures were widespread during the first two days of the month, with many locations experiencing their warmest September temperature on record. A few locations even topped 100 degrees F (37.8 degrees C), which is extremely rare for this late in the year. For example, Pueblo, Colorado tied for its warmest September temperature on record on the 1st (101 degrees F/38.3 degrees C) only to have a new record set the very next day with 102 degrees F (38.9 degrees C) (period of record 1888-2019). This record of 102 degrees F (38.9 degrees C) was then tied only a few days later on the 5th! Denver, Colorado also hit 100 degrees F (37.8 degrees C) on the 2nd, which was the latest 100 degrees F (37.8 degrees C) day on record (period of record 1872-2019). This was a full two weeks after the previous record, which was set on August 16, 2002.
  • Heavy precipitation continued to impact portions of the High Plains region this month, with areas of North Dakota, South Dakota, northwestern Wyoming, and northern and eastern Nebraska receiving precipitation in excess of 200 percent of normal. A large area of western North Dakota had the largest departures with several locations receiving 400-800 percent of normal precipitation. This resulted in many locations in the Dakotas ranking in the top 10 wettest Septembers on record, including Williston, ND (wettest); Grand Forks, ND (wettest); Bismarck, ND (2nd wet­test); Sisseton, SD (2nd wettest); Aberdeen, SD (5th wettest); and Rapid City, SD (9th wettest).
  • Throughout the month of September, several rounds of showers and thunderstorms affected northern areas of the region. Some of these storm systems brought severe weather, which is not necessarily uncommon in the fall. During the overnight hours of the 10th leading into the morning hours of the 11th, a large complex of severe thunderstorms developed over far northern Nebraska and eastern South Dakota. These storms moved slowly, dumping heavy rain over some of the same areas that have experienced flooding off and on much of the year. These storms also produced three EF-2 tornadoes in Sioux Falls, South Dakota. Widespread straight-line wind damage was also reported in the Sioux Falls area from these storms. Due to the slow movement of the thunderstorm complex, heavy rain was widespread. For instance, in Hutchinson County, which is located to the southwest of Sioux Falls, 5.54 inches (141 mm) of rain fell at the Emery 10.8 S CoCoRaHS station. Heavy rain returned to the area later in the day, and ultimately, two-day rainfall totals of 5.00-10.00 inches (127-254 mm) were reported, with some higher amounts in isolated areas. In addition to flash flooding, record crests on the Big Sioux River and James River were observed in the days following this heavy precipitation event. Fields, buildings, and many roads were inundated, including portions of I-90, which was closed in eastern South Dakota for a period of time. Some evacuations and water rescues also occurred.
  • Further south, drier conditions prevailed across the remainder of the region. This was a welcome break from the heavy rain and flooding that has impacted so many in recent months. However, in some areas, such as western Wyoming, western and central Colorado, and southwestern Kansas, abnormally dry and moderate drought conditions have expanded or developed. Persistently drier than normal conditions over the last three months has been a key factor in the recent expansion of moderate drought.
  • The 2019 runoff season is on track to be one of the highest on record. As of October 1, 2019, the U.S. Army Corps of Engineers’ 2019 runoff forecast for the upper Basin (above Sioux City, Iowa) was 61.0 million acre-feet (MAF), which is 241% of average. If realized, this would tie 2011 as the highest upper Basin runoff since records began 121 years ago. This updated runoff forecast is higher than previous forecasts, as heavy rain and wet soils contributed to record-breaking runoff in September. According to the U.S. Army Corps of Engineers’ weekly report, September runoff for the upper Basin was over four times higher than average and twice the previous record. Outside of the upper Missouri River Basin, much above normal and record high streamflows were present across other areas of the region, including Kansas, Nebraska, and portions of the Red River of the North in North Dakota.
  • Slight changes in drought conditions occurred this month, with both improvements and degradations. According to the U.S. Drought Monitor, the area experiencing drought or abnormally dry conditions (D0-D4) in the High Plains region increased over the past month, from approximately 12 percent to 21 percent. This included improvements to drought conditions in north-central North Dakota, and the development, or expansion, of drought conditions in portions of western Colorado and southwestern Kansas. Multiple rounds of showers and thunderstorms impacted the High Plains region this month, especially across northern areas. This rainfall was beneficial for portions of north-central North Dakota and northeast Nebraska, where drought and abnormally dry conditions were eliminated by the middle of the month. Other areas of the region, however, were much drier. For instance, abnormally dry conditions (D0) expanded in parts of Colorado and Wyoming. Moderate drought (D1) expanded in southwestern Colorado and a small pocket of D1 also developed just northeast of this area. Meanwhile, across Kansas, D0 expanded over the southwestern portion of the state, with a slight expansion of D1 as well. Consistently below-normal precipitation over the past three months in portions of Colorado and Kansas has been a key factor to the recent D1 expansion.
  • For more information, please visit the High Plains Regional Climate Center Home Page.

Southern Region (Information provided by the Southern Regional Climate Center)

  • Temperatures for the month of September were above normal across the Southern Region, with every state experiencing a top-3 warmest September on record. Parts of southeastern, southern, and western Texas; central, western, and southeastern Louisiana; southern Mississippi; and northern and eastern Tennessee experienced temperatures 4 to 6 degrees F (2.22 to 3.33 degrees C) above normal. Parts of northern Louisiana; central and northern Mississippi; northern, eastern, central, and southern Texas; and most of Tennessee, Arkansas, and Oklahoma experienced temperatures 6 to 8 degrees F (3.33 to 4.44 degrees C) above normal. Parts of central, northern, and eastern Texas; western and eastern Oklahoma; southern, northwestern, and eastern Arkansas; northern Mississippi; and southwestern Tennessee experienced temperatures 8 to 10 degrees F (4.44 to 5.56 degrees C) above normal. The statewide monthly average temperatures were as follows: Arkansas – 80.00 degrees F (26.67 degrees C), Louisiana – 82.50 degrees F (28.06 degrees C), Mississippi – 81.30 degrees F (27.39 degrees C), Oklahoma – 79.70 degrees F (26.50 degrees C), Tennessee – 76.30 degrees F (24.61 degrees C), and Texas – 81.40 degrees F (27.44 degrees C). The statewide temperature rankings for September were as follows: Arkansas (first warmest), Louisiana (first warmest), Mississippi (second warmest), Oklahoma (second warmest), Tennessee (third warmest), and Texas (first warmest). This was also the warmest September on record for the Southern Region. All state rankings are based on the period spanning 1895-2019.
  • Precipitation values for the month of September were below normal across much of the Southern Region. Parts of central, eastern, and northern Texas; western and eastern Oklahoma; northern, eastern, central, and southern Arkansas; and most of Louisiana, Mississippi, and Tennessee received 50 percent or less of normal precipitation. Parts of central, eastern, and southwestern Texas; western Oklahoma; southern, central, and eastern Arkansas; northern, northeastern, and southeastern Louisiana; and most of Tennessee and Mississippi received 25 percent or less of normal precipitation, while parts of central and eastern Texas; southern, central, and northern Mississippi; and western and eastern Tennessee received 5 percent or less of normal precipitation. In contrast, parts of northern, western, and southeastern Texas; southwestern Louisiana; and eastern Oklahoma received 150 percent or more of normal precipitation. Parts of southeastern Texas and southwestern Louisiana received precipitation 200 percent or more of normal, while parts of southeastern Texas received precipitation 300 percent or more of normal due in part to Tropical Storm Imelda. The statewide precipitation totals for the month were as follows: Arkansas – 1.93 inches (49.02 mm), Louisiana – 1.83 inches (46.48 mm), Mississippi – 0.39 inches (9.91 mm), Oklahoma – 2.95 inches (74.93 mm), Tennessee – 0.40 inches (10.16 mm), and Texas – 2.48 inches (62.99 mm). The state precipitation rankings for September were as follows: Arkansas (twenty-seventh driest), Louisiana (eleventh driest), Mississippi (first driest), Oklahoma (sixty-second driest), Tennessee (second driest), and Texas (fiftieth driest). This was the eighth driest September on record for the Southern Region. All state rankings are based on the period spanning 1895-2019.
  • Drought and Severe Weather:
    • At the end of September, drought conditions continued to deteriorate across the Southern Region. While extreme drought conditions improved across southwestern Oklahoma and deep south Texas, extreme drought conditions developed across central and southern Texas. Severe drought classifications were still present in central and southern Texas as well as southwestern Oklahoma, while new areas developed in eastern and central Texas, southeastern Tennessee, northwestern and northeastern Louisiana, and southwestern Arkansas. Moderate drought classifications expanded across central and northern Texas, western Oklahoma, northern Louisiana, southern Arkansas, western Mississippi, and most of Tennessee. There was an increase in the overall area experiencing abnormally dry conditions as abnormally dry conditions developed or expanded across northern, western, and eastern Mississippi, northern Louisiana, and southern, western, and eastern Arkansas.
    • In September, there were a total of 96 storm reports across Oklahoma, Texas, Arkansas, Louisiana, Mississippi, and Tennessee. There were 6 tornado reports, 8 hail reports, and 82 wind reports. Texas tallied the most tornado (5), hail (3), and wind (25) reports. Unsurprisingly, Texas tallied the most reports total (33), while Arkansas tallied the fewest (10). Two states (Texas and Louisiana) reported tornadoes, while every state with the exception of Mississippi reported at least one hail report.
    • A tropical system impacted the region this month in the form of Tropical Storm Imelda, which made landfall in southeastern Texas on September 17, 2019. Three rain gauges in southeastern Texas reported receiving over 40 inches of rain for the period from September 16 – 20, while 14 rain gauges reported receiving over 20 inches of rain during this same period. Imelda’s preliminary rainfall total places it as the fourth-wettest tropical system to impact Texas and the seventh-wettest tropical system to impact the United States.
    • On September 9, 2019, a wind gust of 85 mph (136.79 kph) was reported near Start, Louisiana. One injury was reported near Moselle, Mississippi after an awning collapsed on a teacher at an elementary school.
    • On September 10, 2019, a wind gust of 59 mph (94.95 kph) was reported near Gallatin, Tennessee. Several reports of downed trees and power lines as well as a couple reports of property damage from high winds were reported in parts of Texas and Tennessee.
    • On September 12, 2019, a wind gust of 78 mph (125.53 kph) was reported at Vance Air Force Base, Oklahoma. A wind gust of 77 mph (123.92 kph) was also reported near Weatherford, Oklahoma.
    • On September 17, 2019, a wind gust of 66 mph (106.22 kph) was reported in Baton Rouge, Louisiana, flipping four aircraft and damaging hanger doors at the Baton Rouge Metropolitan Airport.
    • On September 18, 2019, three tornadoes were reported in southeastern Texas coinciding with Tropical Storm Imelda. No injuries were reported with these tornadoes.
    • On September 19, 2019, a tornado was reported near Hackberry, Louisiana. Also, a wind gust of 60 mph (96.56 kph) was reported near Stinnett, Texas.
    • On September 20, 2019, a wind gust of 65 mph (104.61 kph) was reported near Hereford, Texas.
    • On September 24, 2019, two landspout tornadoes were reported near Sierra Blanca, Texas, while a wind gust of 60 mph (96.56 kph) was reported near Burneyville, Oklahoma.
    • On September 28, 2019, a wind gust of 73 mph (117.48 kph) was reported near Earth, Texas.
    • On September 29, 2019, a wind gust of 66 mph (106.22 kph) was reported near Wink, Texas.
  • For more information, please visit the Southern Regional Climate Center Home Page.

Western Region (Information provided by the Western Region Climate Center)

  • Precipitation was above normal across most of the northern half of the Western U.S. as well as portions of southern Arizona and northern California. Elsewhere in the region, drier-than-normal conditions persisted across central California, southern Great Basin, southern Utah, and southern Rockies of Colorado and New Mexico. Across much of the Pacific Northwest and northern Rockies, precipitation was well above normal providing further relief to drought-stricken areas of northern Idaho, northwestern Montana, and northern and western portions of Washington. In Alaska, wetter-than-normal conditions prevailed in areas experiencing drought in Southcentral and Southwest Alaska while below-normal precipitation continued across much of Southeast Alaska. Average temperatures were above normal across the eastern half of the West with the greatest positive anomalies observed across eastern portions of Colorado and New Mexico while the remainder of the West varied closer to near normal.
  • In the Pacific Northwest, the cool-season started on a positive note after a drier-than-normal winter last year across the Cascades and northern Rockies of northern Idaho and northwestern Montana. According to the NRCS SNOTEL network, all major drainage basins (2-digit HUC regions) in the Pacific Northwest and northern Rockies reported above-normal precipitation for September. In Montana, a major early-season snowstorm impacted northwestern and north-central portions of the state with snowfall totals ranging from 12 to 52 inches. In Great Falls, a two-day snowfall total of 19.3” (49 cm) was observed at the airport that broke the all-time September total snowfall record (dating back to 1937). In eastern Montana, precipitation was well above normal with the Glasgow International Airport reporting 4.57 in (116 mm – 486% of normal). Other locations reporting above-normal precipitation in the Pacific Northwest included: Medford Rogue Valley Airport, OR 1.86 in (47 mm – 326% of normal); Omak, WA 2.9 in (74 mm – 500% of normal); and Idaho Falls Regional Airport, ID 2.1 in (53 mm – 250% of normal).
  • In the Four Corners states, warm and generally dry conditions prevailed across most of the region with the exception of some isolated areas in central and southern Arizona, southwestern New Mexico, and northern Utah that observed above-normal precipitation accumulations. In southern Arizona, the observing station at Patagonia Paton Center received 4.53 in (115 mm – 296% of normal), which represented the 5th wettest September on record dating back to 1921. In contrast, southern portions of Colorado and Utah experienced below-normal precipitation with areas falling into the bottom 10th percentile ranking for the month. In eastern portions of Colorado and New Mexico, anomalously warm temperatures were observed including at the Tucumcari Municipal Airport (NM), which logged its warmest September on record with an average temperature of 78.1° F (25.6°C) – a +8.2° F (4.5°C) departure from normal. In southeastern Colorado, average temperatures in Lamar were +6.1° F (3.4°C) above normal.
  • In California and the Great Basin of Nevada, above-normal precipitation was observed in northern portions of California and Nevada including some early-season snowfall in the northern Sierra and mountain ranges of northern Nevada. In northeastern Nevada, the Elko Regional Airport reported 2.39 in (61 mm – 419% of normal), which marked the 3rd wettest September on record dating back to 1888. In northern California, the northern Sierra town of Quincy received 1.78 in (45 mm – 220% of normal) for the month.
  • In Alaska, warmer-than-normal temperatures continued across the state in September with the greatest departures observed along the North Slope including at the Barrow Airport (Utquagvik, AK) that observed an average temperature of 40.8° F (4.9°C) – a +8.7° F (4.7°C) departure from normal and the warmest September on record dating back to 1901. Likewise, the Aleutian Island town of Cold Bay experienced its warmest September on record with an average temperature of 52° F (11.1°C), which was a +3.9° F (2.2° C) departure from normal. Across much of Southcentral and Southwest Alaska, precipitation was above normal including at the Illiamna Airport that logged 10.68 in (271 mm – 234% of normal) for the month.
  • In the Hawaiian Islands, average temperatures were above normal (1 to 5 degrees F) across most of the island chain for the month. For precipitation, the Big Island as well as Molokai and Lanai were drier than normal while Kauai, Oahu, and most of Maui were wetter than normal. On Oahu, the Honolulu International Airport observed 2.13 in (54 mm – 304% of normal). On Molokai, above-normal temperatures persisted with the Molokai Airport reporting an average temperature of 82.9° F (28.3°C), which was a +4.6° F (2.6°C) departure from normal and the warmest September on record dating back to 1949.
  • Significant Events for September 2019
    • September 28-30: Early-season snowfall event in Montana:A strong early-season storm delivered record-snowfall to areas of north-central and northwestern Montana including 52 inches at Babb, 48 inches at Browning, and 36 inches at East Glacier, according to preliminary reports from the National Weather Service in Great Falls, Montana.
    • September 18: Arctic sea ice tied for the second lowest minimum extent:According to National Snow & Ice Data Center, the Arctic sea ice extent dropped to 1.6 million square miles (4.15 million square kilometer) – which tied 2007 and 2016 for the second lowest minimum extent measured in the satellite record.
  • For more information, please go to the Western Regional Climate Center Home Page.

Citing This Report

NOAA National Centers for Environmental Information, State of the Climate: National Climate Report for September 2019, published online October 2019, retrieved on August 5, 2020 from https://www.ncdc.noaa.gov/sotc/national/201909.

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