National Overview - April 2015


NCDC 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

More Information


National Overview:



April Extreme Weather/Climate Events

Supplemental April 2015 Information


 Average Temperature Departures (April)
April Average Temperature Departures
 April Percent of Average Precip
April Percent of Average Precipitation

  • Climate Highlights — April
  • April 2015 Statewide Temperature Ranks Map

    April 2015 Statewide Precipitation Ranks Map
    April 2015 Statewide Temperature and Precipitation ranks
  • The April 2015 contiguous U.S. average temperature was 53.1°F, 2.1°F above the 20th century average. This ranked as the 17th warmest April on record and the warmest since 2012. The April contiguous U.S. maximum (daytime) temperature was 65.7°F, 2.3°F above average and the 22nd warmest on record. The April contiguous U.S. minimum (nighttime) temperature was 40.5°F, 1.9°F above average and the 15th warmest on record.
  • Much of the contiguous U.S. was warmer than average, especially the Southeast. The above-average mean temperatures in the Southeast were driven largely by warm minimum temperatures. Florida had its warmest April on record with a statewide average temperature of 75.4°F, 6.1°F above the 20th century average. This exceeded the previous record set in 1908 by 0.7°F. Georgia, South Carolina and Louisiana were also much warmer than average during April.
  • Alabama, Florida, and Georgia each had a record warm average April minimum temperature. Alabama's was 5.5°F above average, Florida's was 8.1°F above average, and Georgia's was 6.4°F above average. Four additional states in the Southeast had a top ten warm April minimum temperature.
  • The April Lower 48 precipitation total was 2.78 inches, 0.26 inch above average, ranking in the wettest one-third of the historical record.
  • Wetter than average conditions stretched from the Southern Plains into the Southeast and Ohio Valley. Kentucky, Louisiana and West Virginia were much wetter than average. Kentucky had its second wettest April on record with nearly twice the average monthly precipitation. The state was plagued by widespread flooding early in the month.
  • Below-average precipitation stretched from the West Coast, through the Northern Rockies and Plains, and into the Northeast. South Dakota had its 11th driest April on record, marking a continuation of drier than average conditions that have impacted the state since the beginning of 2015.
  • Alaska was warmer and wetter than average during April. Interior regions of the state were particularly warm, while the panhandle and southwestern regions were much wetter than average. The statewide April average temperature was 27.7°F, 4.4°F above the 20th century average, and the 11th warmest April since records began in 1925. The statewide April precipitation total was 2.53 inches, 0.64 inch above average, the 11th wettest April on record.
  • According to NOAA data analyzed by the Rutgers Global Snow Lab, the April snow cover extent for the contiguous U.S. was 161,000 square miles, 121,000 square miles below the 1981-2010 average. This was the 10th smallest April snow cover extent for the contiguous U.S. and the smallest since 2012. Above-average snow cover was observed across the Northeast and parts of the Northern Rockies. Below-average snow cover was widespread in the West and the Central and Northern Plains stretching into the Midwest. Across Alaska, the April snow cover extent was 533,000 square miles, 16,000 square miles below the 1981-2010 average and the seventh smallest April snow cover extent for the state. Below average snow cover was observed across western regions of the state.
  • According to the April 28 U.S. Drought Monitor report, 37.4 percent of the contiguous U.S. was in drought, up slightly from 36.8 percent at the end of March. Drought conditions worsened across parts of the Northwest, Northern Plains and Upper Midwest. Over 92 percent of Minnesota and 77 percent of South Dakota were in drought — both states were nearly drought free at the beginning of 2015. Heavy precipitation across parts of the Southern Plains and central Gulf Coast improved both long-term and short-term drought conditions. Exceptional drought conditions remained entrenched in the West.
  • Based on NOAA's Residential Energy Demand Temperature Index (REDTI), the contiguous U.S. temperature-related energy demand during April was 29 percent below average and the 34th lowest in the 1895-2015 period of record.
  • During April, there were 2,238 warm daily temperature records (756 daily warm maximum temperature records and 1,482 daily warm minimum temperature records) broken or tied while there were 1,071 cold daily temperature records (678 daily cold maximum temperature records and 393 daily cold minimum temperature records) broken or tied.
  • Climate Highlights — year-to-date (January 2015-April 2015)
  • Jan-April 2015 Statewide Temperature Ranks Map

    Jan-April 2015 Statewide Precipitation Ranks Map
    January-April 2015 Statewide Temperature and Precipitation ranks
  • The January-April 2015 contiguous U.S. average temperature was 41.1°F, 2.0°F above the 20th century average. This ranked as the 20th warmest year-to-date on record and the warmest since 2012. The January-April contiguous U.S. maximum temperature was 52.8°F, 2.3°F above average and the 16th warmest on record. The January-April contiguous U.S. minimum temperature was 29.5°F, 1.7°F above average and the 22nd warmest on record.
  • Much warmer than average conditions were observed from the Rockies to the West Coast, including Alaska. Maximum and minimum temperatures were both much warmer than average across the region. Arizona and California were both record warm with temperature departures from average of 5.1°F and 6.3°F, respectively. In California, this bested the previous record warm January-April, which occurred last year, by 1.1°F.
  • Below-average temperatures were observed in the Midwest and Northeast, where 11 states were much cooler than average. No state was record cold, but Massachusetts and New York each had their second coldest year-to-date on record; only January-April 1904 was colder for both states.
  • Across the Midwest and Northeast, both maximum and minimum temperature were much below-average during the first four months of 2015, but minimum temperatures generally had a larger departure from average. New York had a record cold minimum temperature for January-April, with a minimum temperature of 12.8°F, 6.0°F below the 20th century average. This was 1.0°F colder than the previous record that was set in 1904.
  • The year-to-date contiguous U.S. precipitation total was 8.49 inches, 0.98 inch below the 20th century average. This tied the 18th driest January-April on record.
  • Above-average precipitation was observed across the Southern Plains and Ohio Valley, where Texas was much wetter than average. Parts of the Southern Plains have been dealing with drought conditions dating back five years, with the wet start of 2015 providing long-term and short-term drought relief across the region. The January-April precipitation total for Texas was 11.12 inches, 4.02 inches above average, and marked the wettest start to a year since 2004.
  • Below-average precipitation was observed from the West Coast, through the Northern Plains, the Midwest and into the Northeast, where 13 states were much drier than average. Following a winter with very little snow, South Dakota was record dry for the first four months of 2015, with a mere 1.68 inches of precipitation, 2.33 inches below average. The previous record dry January-April occurred in 1934, when 1.81 inches of precipitation was observed. California had its third driest start to a calendar year with 5.28 inches of precipitation, 7.67 inches below average. The January-April period of 1977 and 2013 were drier with 5.01 inches and 3.81 inches of precipitation, respectively.
  • Alaska was warmer and wetter than average during the first four months of 2015. The statewide average temperature was 15.7°F, 5.4°F above average, and the ninth warmest in the 1925-2015 record. Northern and southern parts of Alaska were much warmer than average, particularly the panhandle. Interior regions were slightly warmer than average. The statewide average precipitation total was 9.73 inches, 0.56 inch above average, and the 28th wettest year-to-date on record. Central and southwestern regions were drier than average, while the panhandle was wetter than average.
  • Based on REDTI, the contiguous U.S. temperature-related energy demand during January-April was 8 percent above average and the 46th highest in the 121-year period of record.
  • The U.S. Climate Extremes Index (USCEI) for the year-to-date was 40 percent above average and the 15th highest value on record. The warm West and cold Northeast temperature pattern during January-April contributed to the much above average USCEI, with the components that measure both warm and cold daytime and nighttime temperatures being much above average. The USCEI is an index that tracks extremes (falling in the upper or lower 10 percent of the record) in temperature, precipitation and drought across the contiguous United States
    • On the regional scale, the West had a record high CEI for the year-to-date, driven in large part by extremely warm daytime and nighttime temperatures, the spatial extent of drought, and days without precipitation. The Southwest also had a record high CEI for January-April, mostly due to warm daytime and nighttime temperatures and 1-day precipitation totals. The Northwest had its fifth highest CEI for the year-to-date.

**A comparison of the national temperature departure from average as calculated by NCDC's operational dataset (nClimDiv), the U.S. Historical Climatology Network (USHCN), and the U.S. Climate Reference Network (USCRN) is available on our National Temperature Index page.**



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 Climatic Data Center.

  • Northeast Region: (Information provided by the Northeast Regional Climate Center)
  • The average temperature for the Northeast has been colder than normal each month so far in 2015, and April was no exception. The region's average temperature of 45.5 degrees F (7.5 degrees C) was 0.6 degrees F (0.3 degrees C) below normal. Unlike previous months, though, not all states were colder than normal. April temperature departures ranged from 2.1 degrees F (1.2 degrees C) below normal in Maine and Vermont to 1.1 degrees F (0.6 degrees C) above normal in West Virginia. Caribou, ME, had its all-time lowest April temperature with a low of -4 degrees F (-20 degrees C) on the 6th.
  • Also since the start of 2015, the region has averaged below-normal precipitation each month. For April, the Northeast received 3.48 inches (88.39 mm) of precipitation, or 95 percent of normal. State departures ranged from 52 percent of normal in Rhode Island to 164 percent of normal in West Virginia, making it the state's 4th wettest April on record.
  • According to the U.S. Drought Monitor released on April 2, 45 percent of the Northeast was abnormally dry. Dryness eased slightly in parts of Pennsylvania and New York so that by month's end 40 percent of the region was abnormally dry.
  • Through mid-April, river flooding and flash flooding in West Virginia caused numerous road closures and led to multiple water rescues, while heavy rain contributed to mudslides. In northern Maine, ice jams caused flooding. Severe storms damaged buildings and trees in southern parts of the region during the month. On April 9, straight-line winds of up to 80 mph (36 m/s) caused damage in western Pennsylvania and baseball-sized hail fall in western West Virginia. On April 20, an EF-0 tornado touched down in central Pennsylvania and a waterspout was reported on the Chesapeake Bay in Maryland. Two days later, showers associated with a cold front produced a wind gust of 71 mph (32 m/s) at the Philadelphia International Airport. According to the National Weather Service, it was the 4th strongest wind gust on record at the site. The growing season was running up to a month behind schedule for parts of the region due to cold temperatures and lingering snow cover.
  • For more information, please go to the Northeast Regional Climate Center Home Page.
  • Midwest Region: (Information provided by the Midwest Regional Climate Center)
  • Overall, April 2015 temperatures were above normal across much of the region, but only by 1 to 3 degrees F (0.6 to 1.7 degrees C). The month began with unseasonably warm temperatures on April 1st, reaching greater than 80 degrees F (26.7 degrees C) in parts of Iowa, Minnesota, and Missouri, which is significantly above normal for April 1st. Unseasonably warm temperatures continued throughout the Midwest the first three weeks of the month, but took a cold turn starting the 22nd. Low temperatures on April 23rd and 24th prompted freeze warnings across Illinois, Indiana, Michigan, and Ohio as freezing temperatures were widespread both mornings. Lows on April 24th were by far the coldest in these areas, dropping as low as 15 degrees F (-9.4 degrees C) in portions of Michigan and northern Minnesota. Preliminary statewide temperatures show monthly average temperatures close to normal for many states since the warm start and cool end to the month averaged together for near-normal average temperatures. Missouri had the greatest departure from normal for average temperature, with the statewide April temperature 2.1 degrees F (1.2 degrees C) above normal. The other eight Midwest states were within 2.0 degrees F (1.1 degrees C) of normal, and all above normal with the exception of Michigan, which was 0.9 degrees F (0.5 degrees C) below normal.
  • April 2015 precipitation was 150 to 300 percent of normal across the Ohio River Valley after numerous rounds of showers and thunderstorms occurred during the month, while the remainder of the Midwest experienced near to below normal April precipitation. The most significant rainfall event in the Ohio River Valley took place on April 2nd-3rd, where 4 to 6 inches (102 to 152 mm) of rain in some areas produced widespread flash flooding and rivers overflowing their banks in portions of Kentucky, Indiana, and Ohio. The Ohio River Valley has had a very wet spring through April with precipitation totals 4.0 to 10.0 inches (102 mm to 254 mm) above normal in this area, while the rest of the Midwest has been drier than normal so far this spring. April 2015 precipitation totals ranged from only 0.10 inch (3 mm) in northwest Minnesota to 10 to 12 inches (254 to 305 mm) in central Kentucky. April 2015 was the 2nd wettest April on record for Frankfort, KY and Lexington, KY after 11.24 inches (286 mm) was recorded in Frankfort and 11.41 inches (290 mm) of rain was recorded in Lexington for the month. Overall, the preliminary statewide precipitation total for Kentucky was 8.66 inches (220 mm), which is 4.56 inches (116 mm) above normal. On the contrary, five states in the Midwest were drier than normal for April. The greatest departures were in Minnesota, which had a statewide value of only 1.39 inches (35 mm), which is 0.85 inches (22 mm) below normal. Drought conditions worsened as a result of the dry conditions in Minnesota. In northwest Minnesota, moderate drought intensified to severe drought by the end of the month. Snow continued to fall in the upper Midwest throughout the month, with monthly totals topping out at 12 to 15 inches (30 to 38 cm) in the Upper Peninsula of Michigan and northern Wisconsin. These totals were above normal by 2 to 10 inches (5 to 25 cm). A majority of this snow fell during events that occurred during the first and second week of the month.
  • The U.S. Drought Monitor showed worsened drought conditions across Minnesota by the end of April with much of the state classified as moderate to severe drought. However, combined with the observed seasonally warmer temperatures, the dry conditions have provided suitable field work days and planting in the state ahead of normal. Farmers report being optimistic for a good crop provided spring rains finally arrive. Much of Wisconsin, central Michigan, and northern Indiana were classified as abnormally dry by the end of April. Due to the wetter than normal conditions across the Ohio River Valley during April, planting was slightly behind in Indiana, Illinois, Ohio, and Kentucky at the end of the month compared to 5-year averages available via state crop progress reports.
  • It was an active month for severe weather in the Midwest, with the most significant event occurring on April 8th and 9th. The two-day severe weather outbreak produced over 700 reports of hail, wind, and tornadoes across the U.S., with many of them in the Midwest. Seven tornadoes moved through north-central Illinois on April 9th, with the most devastating being an EF-4 that went along a 30-mile (48.3 km) path from Franklin Grove, IL to Fairdale, IL, killing 2 people and injuring 22 more. Other notable severe weather events in April included tornadoes in southwest Missouri on April 2nd and 3rd and severe weather in Kentucky on April 25th.
  • Unseasonably cold temperatures in March resulted in lingering ice cover on the Great Lakes into April, with the total ice cover at the beginning of the month at 47.6%. Lake Superior in particular still had quite a bit of ice cover at the beginning of the month, with about 60% of the lake ice covered on April 1st. As April progressed, warmer temperatures reduced ice cover on Lake Superior to around 10% by the end of the month, which is much lower than the end of April last year when ice cover was still around 40% on Lake Superior. Throughout the month of April, total Great Lakes ice cover decreased by about 42%, with the month-end ice cover at 5.7%. This is lower than the end of April last year when ice cover was still at 23.5%, which lingered as a result of the record-breaking ice cover and cold temperatures throughout the winter and spring of 2014.
  • 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 in April were above average across much of the Southeast region. The greatest departures were found across Florida and portions of southern Alabama and Georgia, where monthly temperatures were 5 to 8 degrees F (2.8 to 4.4 degrees C) above average. A total of 17 long-term (period of record exceeding 50 years) reporting stations in Florida observed their warmest April mean temperature on record. A few of these locations include Tallahassee (1893-2015), Tampa (1890-2015), Fort Myers (1892-2015), and Miami (1896-2015). These unusually warm conditions were also quite persistent across Florida during the month; for example, the daily maximum temperature at several locations, including Ocala (1896-2015) and Orlando (1892-2015), was 80 degrees F (26.7 degrees C) or greater for all thirty days of the month. This is only the second and third time on record for Ocala and Orlando, respectively, in which all daily maximum temperatures during April were at least 80 degrees F. Miami, FL observed a maximum temperature of 96 degrees F (35.6 degrees C) on the 26th, which is tied for its warmest April maximum temperature on record. Mean temperatures were also above average in Puerto Rico and the U.S. Virgin Islands. Guayama, PR (1914-2015) observed its second warmest mean temperature for April on record. The warmest weather of the month occurred on the 8th and 9th, as moist tropical air surged northward ahead of an approaching mid-latitude cyclone. During this two-day period, daily maximum temperatures exceeded 80 degrees F over much of the region (excluding Virginia) and reached the lower 90s F (32.2 to 33.9 degrees C) across portions of central Georgia and South Carolina. In contrast, the coolest weather of the month occurred on the 5th, as a strong Arctic high pushed southward across the region. Daily minimum temperatures were below 45 degrees F (7.2 degrees C) across a broad area extending from northern Alabama to Virginia, with temperatures dropping into the upper 20s F (-2.8 to -1.7 degrees C) in portions of western North Carolina and Virginia.
  • Precipitation was above normal across much of the Southeast during April. The wettest locations were found across portions of southern Alabama, central Georgia, the western half of the Florida Panhandle, and central Florida. Monthly precipitation totals in these areas were 3 to 8 inches (76.2 to 203 mm) above normal, or 200 to as much as 600 percent of normal. Kissimmee, FL (1959-2015) observed its wettest April on record with 9.14 inches (232 mm) of precipitation, and Jefferson, NC (1896-2015) observed its second wettest April on record with 7.95 inches (202 mm) of precipitation. Slow-moving frontal boundaries were connected with several heavy precipitation events during the month. On the 12th, Mobile, AL (1873-2015) observed its 12th wettest day of any month on record and 4th wettest April day on record with 7.28 inches (185 mm) of precipitation. On the 29th, Key West, FL (1873-2015) observed its third wettest April day on record with 5.28 inches (134 mm) of precipitation. Portions of north-central Florida and the North Carolina coastal region observed unusually dry conditions during the month, where monthly precipitation totals were 75 to as little as 25 percent of normal. Precipitation was also below normal for much of Puerto Rico and the U.S. Virgin Islands during April. Juncos, PR (1931-2015) observed its third driest April on record with only 0.58 inch (14.7 mm) of precipitation.
  • There were 477 severe weather reports across the Southeast during April, and over 70 percent of these reports were for damaging thunderstorm winds. At least one severe weather report was recorded within the region on 20 days during the month, but nearly 80 percent of these reports were associated with severe weather outbreaks that occurred on just three days during April (19th, 20th, and 25th). There were several reports of large hail across the region, including 2.25 inch (hen egg-sized) hail in Franklin County, NC on the 8th of the month and 2.75 inch (baseball-sized) hail in Laurens County, GA on the 25th of the month. On the 25th, damaging straight-line winds exceeding 75 mph, associated with a cluster of severe thunderstorms, resulted in the fatalities of six sailors participating in the Dauphin Island Regatta near Mobile, AL. A vigorous squall line produced straight-line winds exceeding 80 mph in the vicinity of Savannah, GA later that day. A woman in downtown Savannah was injured when a tree fell on her house. Twenty-four tornadoes were confirmed across the Southeast in April, including 7 EF-0s, 15 EF-1s, and 2 EF-2s. The tornado activity was confined to the southern portion of the region, as no tornadoes were reported in North Carolina or Virginia. One of the more devastating tornadoes occurred on the 19th of the month, when an EF-1 tornado destroyed a mobile home in Calhoun County, SC and injured two residents. On the same day, an EF-1 tornado tracked approximately 39.1 miles across the three states of Florida, Alabama, and Georgia, causing extensive damage to trees, power lines, and built structures along its path. On the 9th of the month, lightning strikes from separate thunderstorms caused the deaths of two North Carolina residents, a man waiting in a mall parking lot in Cary, NC and a woman standing outside of her home in Harnett County.
  • An improvement in drought conditions was observed across the region during April. The percentage of the region under drought-free conditions (less than D1) increased from approximately 96 percent on March 31st to 99 percent on April 28th. Moderate (D1) drought conditions were completely eliminated in southern Alabama and the western half of the Florida Panhandle, and the localized coverage of severe (D2) drought conditions in Miami-Dade County was also ameliorated. Only a small portion of far southern Florida remained in moderate drought at the end of the month. While the unusually warm temperatures during April promoted rapid growth in the corn fields of Georgia, excessive amounts of precipitation leached fertilizers below the root zone of the corn plants, causing a deficiency in the uptake of these essential nutrients. The wet conditions during April also contributed to the development of a fungal disease, known as fusarium head blight, within some Georgia wheat fields.
  • 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 )
  • April 2015 was mild with a wide range in precipitation across the High Plains Region. Generally, average temperatures ranged from near normal up to 4.0 degrees F (2.2 degrees C) above normal. Only isolated areas were outside of this temperature range. Precipitation varied widely, however, with areas like southeastern Wyoming receiving over 200 percent of normal precipitation, while areas such as central South Dakota failed to reach 25 percent of normal. This translated into precipitation surpluses in excess of 1.50 inches (38 mm) across southeastern Wyoming, northeastern Colorado, and a portion of the Nebraska panhandle. On the other end of the spectrum, deficits of at least 1.50 inches (38 mm) were common across central and eastern South Dakota. The dry weather had both positive and negative impacts this month. Early in the season, dry weather can have a positive impact on agriculture. For instance, dry areas in the Dakotas have been good for farming activities as drier soils have allowed for field work to commence with some early planting of small grains, like oats and spring wheat. The dry weather also had some negative impacts, such as an increased risk of wildfires. Wildfires are not uncommon in the spring and this month was no exception, especially across the Dakotas. Multiple reasons for the increased risk include an abundance of fuel built up from the past few years, low snowpack this winter, and overall low precipitation totals. North Dakota had many wildfire issues this month. For example, in mid-April, a grass fire came very close to the campus of University of Mary, just outside of Bismarck, North Dakota. The university closed for one evening and some students were evacuated to a neighboring college. Additionally, I-29 from Grand Forks to the Canadian border was closed due to smoke from grass fires. According to the May 1st release of the National Significant Wildland Fire Potential Outlook from the National Interagency Fire Center, the potential for significant wildfires across the Dakotas should return to normal during May.
  • Unlike the last few months, temperatures were largely near normal across the High Plains region with many locations ending the month within 2.0 degrees F (1.1 degrees C) of normal. Much of Kansas, Nebraska, and South Dakota, however, were in the 2.0-4.0 degrees F (1.1-2.2 degrees C) above normal range. Isolated areas on this eastern side of the region were on the high end of this range. This allowed a few locations to rank in the top 20 warmest Aprils on record, including Aberdeen (18th), Huron (18th), and Pierre (19th) in South Dakota, Norfolk (19th) in Nebraska, and Wichita (18th) in Kansas. Although monthly records were not broken this April, there were some daily records set throughout the month. April 22nd was a particularly chilly morning with numerous record lows set across the region. Minimum temperatures ranged from the mid 40's (7.2 degrees C) in southern Kansas to the mid-teens (-9.4 degrees C) in the Dakotas. Aberdeen, South Dakota was one of these locations and with a minimum temperature of 15 degrees F (-9.4 degrees C) a new daily record was set (period of record 1893-2015). This broke the 1956 record by 5 degrees F (2.8 degrees C). It is not unusual to have a hard freeze in late April in places like Nebraska and the Dakotas. For example, the last spring freeze (at 28.0 degrees F / -2.2 degrees C) in the Dakotas usually occurs somewhere between mid-April to mid-May.
  • For the High Plains region, there was a wide range in precipitation this month with totals ranging from 5 to 300 percent of normal. Areas of the Dakotas largely missed out on precipitation and this was reflected in the latest release of the U.S. Drought Monitor. Two large areas in central and eastern South Dakota received at best 25 percent of normal precipitation. This area of low precipitation also extended into southeastern North Dakota. Deficits of 1.00-2.00 inches (25-51 mm) were common across these areas. On the other end of the spectrum, an area encompassing southeastern Wyoming, the panhandle of Nebraska, northeastern Colorado, and northwestern Kansas received ample precipitation with totals ranging from 150-300 percent of normal. A few pockets scattered across Nebraska, Kansas, western Wyoming, and central and western Colorado also had precipitation totals of at least 150 percent of normal. The following gives a more detailed look at some of the extremes that occurred this month. On the wet side, wintry weather impacted transportation across southern Wyoming this month as I-80 was closed twice within just a few days. A mid-month snowstorm created treacherous driving conditions which led to multiple accidents and injuries. During the two day period of April 16-17, this stretch received heavy, wet snow with totals generally ranging from 10.0-16.0 inches (25-41 cm). I-80 was closed for about 150 miles (241 km) between Cheyenne and Rawlins for at least 20 hours as a result of the accidents. Just a few days later on the 20th, the interstate closed again as fog and wintry road conditions contributed to another pile-up involving at least 50 vehicles. Meanwhile, on the dry side, much of South Dakota received less than 50 percent of normal precipitation. These low amounts caused most locations across the state to be ranked in the top 20 driest Aprils on record. This dryness is not a recent development, however, as precipitation has been lacking since last fall. For instance, Water Year to Date (October 1 - April 30) precipitation totals rank in the top 10 driest for locations all across the state. Examples include Rapid City in the west (4th), Pierre in the central part of the state (7th), and Aberdeen in the east (3rd). The past couple of months have been particularly dry for Rapid City which has only received 0.76 inches (19 mm) of liquid equivalent precipitation and 1.2 inches (3 cm) of snow over these two months. This marks the 2nd driest and 3rd least snowiest March and April on record for Rapid City (period of record 1942-2015).
  • Although there were small improvements, drought conditions have generally expanded across the High Plains region according to the latest release of the U.S. Drought Monitor. The total area in drought (D1-D4) increased from about 35 percent to nearly 45 percent. South Dakota fared the worst this month. The total area in drought (D1-D4) increased from about 43 percent to 77 percent and a rather large new area of severe drought (D2) has emerged in the central and eastern parts of the state. In these areas, winter wheat winterkill has been an issue. Winterkill can be the result of many factors, including a lack of snow cover in the winter and early spring, and a recent lack of rainfall. Additionally, the National Agricultural Statistics Service (NASS) indicated that topsoil moisture across South Dakota was rated at 69 percent Short or Very Short at the end of the month. Other degradations around the region included an expansion of moderate drought (D1) in eastern North Dakota, northeastern Nebraska, and southwestern Wyoming. Meanwhile, in south-central Kansas, D2 expanded slightly and a new area of extreme drought (D3) emerged as well. Improvements were made in only a few areas, such as western Colorado where a small area of D2 was improved to D1. Additionally, abnormally dry conditions (D0) were removed from northeastern Colorado, portions of central Nebraska, an area of west-central North Dakota, and a very small area of eastern Kansas. Several chances for thunderstorms in the first week of May could lead to more improvements across the region.
  • For more information, please go to the High Plains Regional Climate Center Home Page.
  • Southern Region: (Information provided by the Southern Regional Climate Center)
  • Although there were small improvements, drought conditions have generally expanded across the High Plains region according to the latest release of the U.S. Drought Monitor. The total area in drought (D1-D4) increased from about 35 percent to nearly 45 percent. South Dakota fared the worst this month. The total area in drought (D1-D4) increased from about 43 percent to 77 percent and a rather large new area of severe drought (D2) has emerged in the central and eastern parts of the state. In these areas, winter wheat winterkill has been an issue. Winterkill can be the result of many factors, including a lack of snow cover in the winter and early spring, and a recent lack of rainfall. Additionally, the National Agricultural Statistics Service (NASS) indicated that topsoil moisture across South Dakota was rated at 69 percent Short or Very Short at the end of the month. Other degradations around the region included an expansion of moderate drought (D1) in eastern North Dakota, northeastern Nebraska, and southwestern Wyoming. Meanwhile, in south-central Kansas, D2 expanded slightly and a new area of extreme drought (D3) emerged as well. Improvements were made in only a few areas, such as western Colorado where a small area of D2 was improved to D1. Additionally, abnormally dry conditions (D0) were removed from northeastern Colorado, portions of central Nebraska, an area of west-central North Dakota, and a very small area of eastern Kansas. Several chances for thunderstorms in the first week of May could lead to more improvements across the region.
  • April was a wetter than normal month for all six states in the Southern Region. Precipitation totals varied spatially with each state showing some dryness in select counties/parishes. A series of low pressure systems moved across the Gulf coast, bringing anomalous precipitation totals. Most stations in Southern Texas and Louisiana reported over one and a half times the normal allotment. Similar values were also observed in northern and eastern Texas and central Oklahoma. In the case of the latter, precipitation totals of over three times the monthly normal were observed. The state-wide average precipitation totals for the month are as follows with: Arkansas reporting 5.72 inches (145.29 mm), Louisiana reporting 8.21 inches (208.53 mm), Mississippi reporting 6.19 inches (157.23 mm), Oklahoma reporting 4.80 inches (121.92 mm), Tennessee reporting 5.72 inches (145.29 mm), and Texas reporting 3.91 inches (99.31 mm). The state of Louisiana reported its ninth wettest April on record (1895-2015), while for Texas it was their fifteenth wettest April (1895-2015). Oklahoma recorded its nineteenth wettest April, and for Tennessee, it was their twenty-sixth wettest April on record (1895-2015). The remaining state-wide rankings fell within the two middle quartiles.
  • Drought conditions in the Southern Region improved significantly for the second consecutive month. Anomalously high precipitation has led to a large reduction in the areal coverage of extreme and exceptional drought. As of April 28, 2015, only 6.05 percent of the Southern Region was classified as extreme drought or worse, compared to 12.60 percent on March 31, 2015. Along the central Gulf coast, heavy rains have alleviated all drought conditions in southern Louisiana and southern Mississippi.
  • Because of the large amount of lows and frontal systems that passed through the region in April, the number of severe weather events was extremely high. In fact, there were only a few days during the month where no severe weather was reported in the Southern Region. The most widespread severe weather occurred on the following days of the month: April 16, 17, 18, 19, 22, 24, 26, and 27. On April 24, over a dozen tornadoes were reported covering three states: Texas, Louisiana, and Mississippi. Fortunately no injuries or fatalities were listed. Baseball-sized hail was reported in St. Martin, Louisiana, with wind gusts that were estimated at around 65 mph (104.61 kph). On April 27, classes at Louisiana State University were canceled when straight line winds associated with a squall line passed through Baton Rouge. Over 50,000 people were without power.
  • April was a very wet month for Texas, especially in Houston where 8.20 inches (208.28 mm) of rain was recorded. This was the sixth wettest April on record for the area. Amarillo is doing better in the rainfall department as well, by having a day of record rainfall at the end of the month with 1.71 inches (43.43 mm) in 24 hours. Moreover, Gainesville saw up to 5 inches (127 mm) of rain during one storm. The heavy rains this month proved valuable for wheat growers, but more problematic for other crops. Onions are growing great, along with peaches due to the cool winter. The warmer and wetter spring, however, is causing concern over invasive weed growth in the coming months. Muddy and soggy grounds in the wettest portions of the state are causing issues for farmers that are wanting to plant crops for the spring growing period as soil moisture is still running too high. Ecologically, cattle are still doing well and have plentiful water in their stock tanks from the rain. As for the drought conditions, as of the end of the month only sixteen percent of the state is under severe drought or worse. This is the lowest percentage since November of 2010. Statewide, reservoirs now stand at 73.9 percent full, which is nearly a four percent jump since the end of March, which included a nine percent increase in storage in North Central Texas, easing sprinkler use restrictions for the first time since 2013 West Central Texas and the Highland Lakes have not improved as much, however, with Austin area reservoirs still sitting at forty percent and mandatory Stage 1 water restrictions being considered by the Brazos Valley River Authority (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 Region Climate Center)
  • April brought near to slightly below normal temperatures to the West, breaking a four-month stretch of widespread above normal temperatures. This month showed a typical springtime transitional pattern, with two cold storm systems passing across much of the West interspersed with strong high pressure and above normal temperatures. Precipitation was variable across the West, though generally below normal. Scattered areas of the Southwest observed above normal precipitation.
  • The West saw periods of above and below normal temperatures this month that averaged to near normal for the month. Some parts of the Southwest experienced less variability this month and saw climatologically significant monthly temperatures. California statewide was warmer than average for a 16th consecutive month. San Diego, California, recorded an average April temperature of 65.8 F (18.8 C), 4 F (2.2 C) above normal, the second warmest April since records began in 1939. For the first time in 2015, Los Angeles, California and Tucson, Arizona did not have monthly average temperatures among the top-10 on record. Los Angeles recorded an average 65.8 F (18.8 C) for April, 2.7 F (1.5 C) above normal, the 11th warmest April in a 139-year record. The Tucson average of 69 F (20.6 C) was 2 F (1.1 C) above normal and 16th warmest since records began in 1946. On the cooler than normal side, temperatures at Bozeman, Montana averaged to 41.9 F (5.5 C) for April, 3.2 F (1.8 C) below normal. This value fell within the middle tercile of April temperature observations in this station's 75 years of record. Elsewhere in the West, temperatures were generally within 1-2 F (0.5-1 C) of normal.
  • Precipitation was variable across the West this month, though several areas received beneficial rain and snow. Sacramento, California received 1.82 in (46 mm) precipitation for the month, 140% of normal, its first month in 2015 with above normal precipitation. Scattered areas of above normal precipitation were observed in the desert region along the California-Arizona border. Lake Havasu City, Arizona, observed 0.97 in (25 mm), 1600% of the normal 0.06 in (2 mm). Most of this fell during a storm on the 24th. A large area of northwestern Nevada also experienced above normal April precipitation. Winnemucca reported 1.83 in (46 mm), 206% of normal, the 12th wettest April in its 139-year record. Elsewhere in the Southwest, southeastern New Mexico received ample April precipitation. Roswell logged its 13th wettest April in a 123-year record with 1.74 in (44 mm), 1.13 in (29 mm) above normal. Nearly all of this precipitation fell on the 15th. In southeastern Utah, Moab recorded 1.82 in (46 mm) for April, 219% of normal and the 9th wettest April since records began in 1893. Following a dry March, Colorado's Front Range received beneficial April precipitation. Boulder observed 4.5 in (114 mm) for the month, 156% of normal and the 15th wettest April in a 123-year record.
  • Near to well above normal temperatures were observed across Alaska this month. Anchorage recorded its warmest April on record at an average 40.7 F (4.8 C), 3.9 F (2.2 C) above normal; records there began in 1952. Precipitation was significantly above normal across southern Alaska. King Salmon reported 2.18 in (55 mm) precipitation, 223% of normal, the 6th wettest April in a 99-year record. Further south, several locations in Hawaii saw wetter than normal conditions and lessening of drought on all major islands. Kahului, Maui, recorded 2.81 in (71 mm) rainfall, 181% of normal. Temperatures were also above normal in many locations throughout the state. On the windward side of Oahu, Kaneohe recorded an average 77.3 F (25.2 C) for the month, 3.2 F (1.8 C) above normal and the warmest April since records began in 1942.
  • April (all month): Severe drought persists in California/Nevada/Oregon: Precipitation in parts of California and Nevada was far from sufficient to alleviate multi-year drought conditions. The region's precipitation season is coming to an end and this winter's meager snowpack promises little runoff for the spring and summer months, suggesting the drought may intensify. California's governor declared a mandatory 25% reduction in urban water use and the replacement of 50 million square feet of lawn with artificial turf or drought tolerant landscapes, among other actions.
  • April 14: Dust storms affect Salt Lake City, Utah and Las Vegas, Nevada: Strong winds ahead of a low pressure system produced dust storms that reduced visibility in these areas. West of Salt Lake City, a 17-vehicle pileup occurred killing 1 person and injuring 25. Additionally, Salt Lake City's air quality was deemed "unhealthy" and 15,000 people were without power. In Las Vegas, 2,000 homes and businesses were without power and felled trees blocked roads and damaged property.
  • For more information, please go to the Western Regional Climate Center Home Page.

Citing This Report

NOAA National Climatic Data Center, State of the Climate: National Overview for April 2015, published online May 2015, retrieved on May 27, 2015 from http://www.ncdc.noaa.gov/sotc/national/201504.