April 2018 Climate and Hydrology Summary

Tulsa: April 2018 was the 2nd coldest (54.1°F, record is 53.4°F in 1907; since 1905), the 20th driest (1.76"; since 1888), and the 4th snowiest (0.1"; since 1900) April on record.

Tulsa: The 2017-18 cold season ranked as the 14th least snowy (tying 1975-76; since records began in 1900-01) with 2.1".

Fort Smith: April 2018 was the 3rd coldest (56.5°F; since 1883) and the 63rd driest (3.63"; since 1883) April on record. No snow fell in April.

Fort Smith: Daily records set or tied this month include a record cold minimum temperature.

Fort Smith: The 2017-18 cold season ranked as the 5th least snowy (since records began in 1883-84) with only a trace of snow (tied 9 other years).

Fayetteville: April 2018 was the Record coldest (51.5°F, previous record 51.6°F in 1983; since 1950), the 5th driest (1.54"; since 1950), and the 3rd snowiest (Trace, tied 14 other years; since 1950) April on record.

Fayetteville: The 2017-18 cold season ranked as the 6th least snowy (since records began in 1949-50) with 0.4" of snow.

Using the radar-derived estimated observed precipitation from the RFCs, rainfall totals for April 2018 ranged from around 1” to isolated amounts around 6” across eastern OK and northwest AR. This corresponds to 20-90% of the normal April rainfall for most of eastern OK and northwest AR. However, portions of Okmulgee, Okfuskee, Muskogee, northern Le Flore, and Sebastian Counties were near normal to near 200% of the normal April rainfall.

It was a cold (5ËšF to 6ËšF below normal) and dry April across eastern Oklahoma and northwest Arkansas. For the State of Oklahoma and Tulsa, OK, April 2018 was the second coldest April on record. This April was the record coldest in Fayetteville, AR and 3rd coldest in Fort Smith, AR.

A new all-time record low temperature for the month of April was established for the State of Arkansas. On April 8th, 2018, the temperature at Kingston 2 S in Madison County (elevation 2,145 feet) fell to 9°F. Officials from the NWS Tulsa office visited the site to verify the accuracy of this reading and it was determined the reading is valid. The reading also corroborated with a couple of other nearby readings of 11°F from a variety of instrument types. Thus, the reading of 9°F at Kingston 2 S on April 8th, 2018 establishes a new record low temperature for the state of Arkansas for the month of April. Since reliable record keeping began in the 19th century in Arkansas, this is the first verified occurrence of a single digit reading in the month of April in the state. The previous record low for Arkansas for the month of April was 12°F, which was recorded at Lead Hill in Boone County on April 13, 1957 and tied on April 8, 2007.

Fayetteville, AR tied for the record latest killing freeze (24°F) with 24°F on April 16, 2018. This tied the record from April 16, 1953. Fort Smith, AR missed the record latest freeze by one day, with a temperature of 32°F on April 16, 2018. The current record is April 17 from 1921 and 1951. Tulsa, OK also missed its record latest hard freeze (28°F) with a temperature of 27°F on April 16, 2018. The current record is April 17, 1921.

There were no tornadoes in Oklahoma in April 2018 (for only the third time), breaking the previous record of April 26, 1962 as the latest first date of a tornado in the state (the 1st tornado of 2018 in OK occurred on May 1 near Buffalo). 2 tornadoes did occur in west central Arkansas this month.

Elevated showers developed during the early morning of the 13th across southeast OK and spread north during the morning as warm air advection increased over the area. A dry line then approached from the west, igniting scattered showers and thunderstorms, some of which became severe, during the afternoon and evening hours. A supercell developed over northeastern Le Flore County Oklahoma during the afternoon. The storm intensified as it moved northeast into northern Sebastian County and southern Crawford County Arkansas, where it produced a strong tornado. Another storm produced a weak tornado over northeastern Sebastian County Arkansas and southwestern Franklin County Arkansas. Information about these events can be found at https://arcg.is/1f5Ob4

According to the Drought Monitor from May 1, 2018, Severe (D2) Drought conditions were impacting northwest Osage, far northwest Pawnee, and eastern Kay Counties in eastern OK. Moderate (D1) drought conditions were present across portions of Osage, Pawnee, Washington, and Nowata Counties in eastern OK. Abnormally Dry (D0) but not in drought conditions encompassed portions of Pawnee, Creek, Osage, Washington, Tulsa, Rogers, Nowata, and Craig Counties.

According to the Oklahoma Climatological Survey, April 2018 was the 11th driest for northeast Oklahoma, the 41st driest for east central Oklahoma, and the 41st driest for southeast Oklahoma. Records go back to 1921. For the Year-to-Date period Jan. 1-Apr. 30, 2018, northeast Oklahoma ranked as the 38th driest, east central Oklahoma was the 10th wettest, and southeast Oklahoma was the 10th wettest period. For the last 365 days (May 1, 2017-April 30, 2018), northeast Oklahoma was the 49th wettest, east central Oklahoma was the 18th wettest, and southeast Oklahoma was the 24th wettest.