@NOAA: National Climate Report – April 2018

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Climate Highlights — April


April 2018 Statewide Temperature Ranks
  • During April, the average contiguous U.S. temperature was 48.9°F, 2.2°F below the 20th century average, making it the 13th coldest April on record and the coldest since 1997.
  • Below-average temperatures were observed from the Rockies to the East Coast. Twenty-two states had an April temperature that ranked among the 10 coldest on record. Eight states had their second coldest April on record and two states—Iowa and Wisconsin—were record cold.
  • Above-average April temperatures were observed across much of the West, with record warm temperatures for parts of the Southwest. Arizona had its second warmest April on record with a statewide temperature 6.3°F above average.
  • Above-average April temperatures were also observed in southern Florida.
  • The contiguous U.S. average maximum (daytime) temperature during April was 61.7°F, 1.7°F below the 20th century average, marking the 21st coolest value on record and coolest since 1997. Below-average maximum temperatures were observed from the Rockies to East Coast, with 19 states having a top 10 cold April maximum temperature. Iowa had a record cold April maximum temperature.
  • The location of record and near-record cold maximum temperature coincided with record-setting April snowfall. Above-average conditions were observed in the Southwest, where Arizona had its second warmest April maximum temperature on record.
  • Nationally, the April minimum (nighttime) temperature was the seventh coldest on record at 36.1°F, 2.6°F below average. Below-average conditions were observed from the Rockies to the East Coast, where nine states had an average minimum temperature for the month that was record cold with fourteen additional states having much-below-average minimum temperatures. Above-average minimum temperatures were observed across the West.
  • The Alaska average April temperature was 26.6°F, 3.3°F above the long-term mean. This ranked among the warmest third of the historical record. St. Paul and Cold Bay each had their fifth warmest April on record. Along the state’s west coast, sea ice continued to be much below average, contributing to the above-average temperatures. Some impacts of the low sea ice reported include coastal erosion and loss of hunting/fishing grounds.
  • During April there were 7,068 record cold daily high (3,778) and low (3,290) temperature records, which was about 2.8 times the 2,563 record warm daily high (972) and low (1,591) temperature records.
  • Based on NOAA’s Residential Energy Demand Temperature Index (REDTI), the contiguous U.S. temperature-related energy demand during April was 82 percent above average and was the fifth highest value in the 124-year period of record. The below-average temperatures in the Northeast and Midwest contributed to the above-average REDTI.
  • Precipitation

    April 2018 Statewide Precipitation Ranks
  • The April precipitation total for the contiguous U.S. was 2.41 inches, 0.11 inch below average, and ranked near the median value in the 124-year period of record.
  • During April, above-average precipitation was observed along the West Coast, Northern Rockies and much of the East. Record high precipitation was observed in parts of the Northwest, with Washington state having its third wettest April on record with 5.53 inches of precipitation, 2.70 inches above average. This was the wettest April for the state since 1996.
  • Below-average precipitation stretched from the Southwest, through much of the Great Plains, where five states had a monthly precipitation total that was much below average. The dry conditions in the Southern Plains provided ideal wildfire conditions with numerous large wildfires burning during the month. Record-low precipitation was observed in parts of the Southwest and mid-Mississippi Valley.
  • According to NOAA data, analyzed by the Rutgers Global Snow Lab, the contiguous U.S. snow cover extent during April was 508,000 square miles, 227,000 square miles above the 1981–2010 average. This was the fifth largest April snow cover extent on record for the Lower 48 since satellite records began 52 years ago, and the largest April snow cover extent since 1997. Above-average snow cover was observed for most northern locations in the nation, with below-average snow cover in the Southwest.
  • Most locations on the Hawaiian Islands had above-average precipitation during April with Lihue having its sixth wettest April and Kula its third wettest. On April 14-15, heavy rain fell across Kauai causing major flooding and landslides. According to preliminary data, a rain gauge near Hanalei, on Kauai’s North Shore, reported 49.69 inches of rain in 24 hours, potentially a new national record. It is pending review by the National Climate Extremes Committee.
  • According to the May 1 U.S. Drought Monitor report, 28.6 percent of the contiguous U.S. was in drought, down from 29.4 percent at the beginning of April. Drought conditions improved in California, the Northern Plains and the Southeast. Drought also improved in parts of the Alaskan panhandle. Drought conditions expanded and intensified in the Southwest and Central to Southern Plains. The percent area of the contiguous U.S. experiencing D4 – Exceptional Drought, the worst category, expanded to 2.2 percent, the highest since November 2016. D4 drought conditions stretched from the Southwest to Southern Plains.
  • @CWCB_DNR Proposed Acquisition of Contractual Interest in Ruedi Reservoir Water for ISF Use

    The dam that forms Ruedi Reservoir, above Basalt on the Fryingpan River. Photo: Brent Gardner-Smith/Aspen Journalism

    From email from the Colorado Water Conservation Board (Rob Viehl):

    DATE: May 16, 2018

    RE: Proposed Acquisition of Contractual Interest in Ruedi Reservoir Water for ISF Use on Fryingpan River, Eagle & Pitkin Counties

    The Colorado Water Conservation Board will be considering a proposal from the Colorado River Water Conservation District, acting through its Colorado River Water Projects Enterprise (“CRWCD”) to enter into a one-year renewable short-term lease of a portion of water that CRWCD holds in Ruedi Reservoir for instream flow (“ISF”) use to boost winter flows in the Fryingpan River below Ruedi Reservoir. The Board will consider this proposal at its May 23-24, 2018 meeting in Salida. The agenda for this Board meeting can be found at:

    Consideration of this proposal initiates the 120-day period for Board review pursuant to Rule 6b. of the Board’s Rules Concerning the Colorado Instream Flow and Natural Lake Level Program (“ISF Rules”), which became effective on March 2, 2009. No formal Board action will be taken at this time.

    Information concerning the ISF Rules and water acquisitions can be found at:

    Click to access Final%20Adopted%20ISF%20Rules%201-27-2009.pdf

    The following information concerning the proposed lease of water is provided pursuant to ISF Rule 6m.(1):
    Subject Water Right:

    Source: Fryingpan River
    Decree: CA4613
    Priority No.: 718
    Appropriation Date: 7/29/1957
    Adjudication Date: 6/20/1958
    Decreed Amount: 140,697.3 Acre Feet

    Decree: 81CW0034(Second Filling)
    Appropriation Date: 1/22/1981
    Adjudication Date: 12/31/1981
    Decreed Amount: 101,280 Acre Feet

    Bureau of Reclamation Contract: 079D6C0106
    Contract Use: Supplement winter instream flows in the Fryingpan River
    Contract Amount: 5,000 Acre Feet
    Amount Offered for Consideration: 3,500 Acre Feet

    Proposed Reaches of Stream:

    Fryingpan River: From the confluence with Rocky Ford Creek, adjacent to the outlet of Ruedi Reservoir, downstream to its confluence with the Roaring Fork River, a distance of approximately 14.4 miles.

    Purpose of the Acquisition:

    The leased water would be used to supplement the existing 39 cfs ISF water right in the Fryingpan River to preserve the natural environment, and used at rates up to 70 cfs to meet the Roaring Fork Conservancy and Colorado Parks and Wildlife flow recommendations to improve the natural environment to a reasonable degree.

    Proposed Season of Use:

    Water stored in Ruedi Reservoir will be released to the Fryingpan River during the winter time period. The existing instream flow water right is decreed for 39 cfs from November 1 – April 30. The objective of the lease would be to maintain Fryingpan River flows at a rate of 70 cfs to prevent the formation of anchor ice at times when temperatures and low flows could otherwise combine to create anchor ice, which adversely impacts aquatic macroinvertebrates and trout fry.

    Supporting Data:

    Available information concerning the purpose of the acquisition and the degree of preservation of the natural environment, and available scientific data can be found on CWCB water acquisitions web page at: http://cwcb.state.co.us/environment/instream-flow-program/Pages/RuediReservoirFryingpanRiver.aspx

    Linda Bassi
    Stream and Lake Protection Section
    Colorado Water Conservation Board
    1313 Sherman Street, Room 721
    Denver, CO 80203
    303-866-3441 x3204

    Kaylea White
    Stream and Lake Protection Section
    Colorado Water Conservation Board
    1313 Sherman Street, Room 721
    Denver, CO 80203
    303-866-3441 x3240