May 2013 Climate and Hydrology Summary

Tulsa: May 2013 was the 23rd coldest (66.8°F; since 1905), the 57th driest (4.71"; since 1888), and the record snowiest (Trace; since1900) May on record.

A trace of snow fell in Tulsa on May 2, 2013, making this the latest trace of snow on record in Tulsa and the first time snow has fallen in the month of May.

Fort Smith: May 2013 was the 51st coldest (69.0°F, tied 1890, 1948; since 1883) and the 52nd wettest (5.40"; since 1883) May on record.

Fayetteville: May 2013 was the 13th coldest (63.6°F; since 1950), the 11th wettest (8.24"; since 1950), and the record snowiest (0.5"; since 1950) May on record.

0.5" of snow fell in Fayetteville on May 3, 2013, making this the latest trace of snow on record in Fayetteville and the first time snow has fallen in the month of May. This is also the latest snowfall recorded in the state of Arkansas, as well as the first time snow has fallen in Arkansas in the month of May.

Using the radar-derived estimated observed precipitation from the RFCs, rainfall totals for May 2013 ranged from 3” to 17”, with a large portion of the area receiving 5”-10”. This resulted in much of the region having 100% to over 200% percent of the normal May rainfall. However, far southeast Oklahoma and portions of northeast Oklahoma southeast of I-44 and north of I-40 only had 50% to 90% of the normal May rainfall.

May 2013 was a tumultuous month across eastern Oklahoma and northwest Arkansas, with snow, tornadoes, flooding, and drought. 13 forecast points went into minor or moderate flood due to rainfall this month, with the Neosho River and Kiamichi River both flooding twice.

Two periods of severe weather and heavy rain affected the region during the second half of May 2013. The first period of storms brought several tornadoes and widespread flooding on May 19-21. At the end of the month, three additional rounds of storms from May 29 through June 1 brought 4 more tornadoes, river flooding, and severe flash flooding. More information about these events are available by following the links.

According to the Drought Monitor from May 28, 2013, only a small portion of eastern Oklahoma remained in Moderate to Severe drought. This Drought Monitor, however, does not include the heavy rain that fell over the drought areas during the last few days of May 2013. As of May 28, severe (D2) drought was present across eastern Kay, Osage, Pawnee, Washington, and Nowata Counties in eastern Oklahoma. Moderate (D1) conditions existed over sections of far western Craig, southeast Nowata, Rogers, Tulsa, and northern Creek Counties in eastern Oklahoma. Abnormally dry conditions continued in portions of Craig, Rogers, Tulsa, southern Creek, Okmulgee, and northern Okfuskee Counties in eastern Oklahoma.

According to the Oklahoma Climatological Survey, the 30-day period May 2-31, 2013 was the 16th wettest for northeast Oklahoma, the 29th wettest for east central Oklahoma, and the 33rd wettest for southeast Oklahoma. Records go back to 1921.

According to the Oklahoma Climatological Survey, for Spring 2013, northeast Oklahoma ranked as 24th wettest, east central Oklahoma ranked as 25th wettest, and southeast Oklahoma ranked as 37th wettest. Records go back to 1921.

Spring (March - April - May) 2013

Tulsa: Spring 2013 was the 4th coldest (56.9°F; since 1905) and the 33rd driest (9.16"; since 1888) Spring on record. For the cold season 2012-13, Tulsa recorded 3.7" of snow, making this the 86th snowiest cold season (since 1900-01).

Fort Smith: Spring 2013 was the 32nd coldest (59.9°F, tied 1969; since 1883) and the 56th wettest (12.55"; since 1883) Spring on record. For the cold season 2012-13, Fort Smith recorded 8.0" of snow, making this the 31st snowiest cold season (since 1883-84).

Fayetteville: Spring 2013 was the 4th coldest (54.3°F; since 1950) and the 11th wettest (18.25"; since 1950) Spring on record. For the cold season 2012-13, Fayetteville recorded 3.1" of snow, making this the 46th snowiest cold season (since 1950-51).

Outlook

The Climate Prediction Center CPC outlook for June 2013 (issued May 31, 2013) indicates equal chances for above, near, and below normal temperatures and precipitation across all of northeast Oklahoma and northwest Arkansas. This outlook is based primarily on dynamical computer models, as well as climate forcing mechanisms such as soil conditions and decadal-timescale climate trends.

For the 3-month period June-July-August 2013, CPC is forecasting an enhanced chance for above normal temperatures and an equal chance for above, near, and below median precipitation across all of eastern Oklahoma and northwest Arkansas (outlook issued May 16, 2013). Tthis outlook is primarily based on recent trends and dynamic computer model output, with some input from statistical forecast tools and long-term trends.

According to CPC, ENSO neutral conditions remained through May. ENSO neutral conditions are expected to continue through Summer 2013, followed by uncertain conditions in the ENSO state from late 2013 and beyond.