monthly climate summary

Considering the extreme precipitation that ended 2015, and with the “super” El Niño that boosted the November-December period to the wettest on record for the state still in place, January was a veritable dud. According to preliminary data from the Oklahoma Mesonet, the statewide average precipitation total was 0.71 inches, nearly an inch below normal and the 28th driest January since records began in 1895. Only 29 of the Mesonet’s 120 stations recorded at least an inch of rain, and only three exceeded 2 inches. Cloudy led all Mesonet sites with 2.45 inches.

Mother Nature managed to save some of the worst of 2015’s weather for last, ending the year with a powerful winter storm that, while significant for western Oklahoma, was historic for the eastern half of the state. The Dec. 26-28 event prompted blizzard, ice storm and winter storm warnings for western Oklahoma while the eastern half was awash in flood-related emergencies. High winds accompanied the storm throughout its stay. The Oklahoma Mesonet recorded 984 wind gusts of at least 50 mph from 10 p.m. on Dec. 26 through 4:15 a.m. on Dec. 28.

Records were threatened, tornadoes were spotted, and ice crippled half of the state while the other half flooded, all thanks to two powerful storm systems during one of the wildest stretches of November weather in state history. The first system struck around mid-month and resembled a classic springtime severe weather setup. A series of supercells sprung up across the High Plains and marched east, dropping as many as five tornadoes in Oklahoma and many more across Texas and Kansas.

It took a bit of convincing, but Mother Nature finally gave the okay for fall to arrive during the final week of October. That change in seasons took the state from a warm, dry pattern that had persisted for the past three months to much more seasonable and rainy weather. Two successive storm systems at the end of the month brought heavy rains to much of southern and western Oklahoma, halting the advance of the flash drought that began during the heat of August. Those areas saw between 3-7 inches of rain, and in some areas of south central Oklahoma, more than 9 inches of moisture fell.

Flash drought continued to spread across southern Oklahoma during a dry, hot September, and had enveloped nearly 17 percent of the state by month’s end. According to preliminary data from the Oklahoma Mesonet, the statewide average rainfall total was 1.43 inches below normal at 2.1 inches, the 33rd driest September since records began in 1895. It was particularly dry across south central and southeastern Oklahoma, areas that had seen record rainfall from April through July.

Many a rainy summer has stared into the unyielding gaze of August and faltered. Coming off the wettest May-July period on record for Oklahoma, this August was met with similar expectations. In that regard, however, it was an unmitigated failure with preliminary data from the Oklahoma Mesonet indicating a statewide average of 2.3 inches. That is more than half an inch below normal and ranks the month as the 46th driest August on record, dating back to 1895. The northeast saw a surplus of more than 1.7 inches to rank as the 24th wettest August for that area.

The heavy rains of spring continued right through the first week of July before finally giving way to a more typical summertime pattern. Rainfall totals during July were particularly excessive from south central through east central Oklahoma, with widespread amounts of 10-15 inches through that area. According to preliminary data from the Oklahoma Mesonet, the statewide average for the month was 5.89 inches, 3.01 inches above normal and the sixth wettest July since records began in 1895.

Mother Nature turned off the spigot and cranked up the heat during the first 10 days of June, allowing swollen streams, rivers and reservoirs to slowly recede after the record May rains. The respite was short-lived, however, thanks to a tropical invasion from both the Pacific and Atlantic. First up was the remnant of hurricane Blanco from the Pacific that interacted with a stalled front and dumped 2-4 inches of rain over a wide swath of the state, including more than 10 inches near Hollis in far southwestern Oklahoma.

Historic rains during May virtually eliminated the drought that had plagued Oklahoma for much of the past five years. The storms that brought that relief came with a cost, however, spawning more than 60 tornadoes, catastrophic flooding, and the highest price of all, 11 fatalities. The rains began during the first week of May and by the end of the month the state had seen the most rainfall on record for any month in its history. The statewide average, as measured by the Oklahoma Mesonet, finished at 14.40 inches, 9.58 inches above normal.

Mired in significant drought for much of the last five years, western Oklahomans have been in desperate need of moisture. Mother Nature finally granted that wish and provided abundant rainfall during April. Much of Oklahoma saw at least 4-6 inches of rain during the month. According to preliminary data from the Oklahoma Mesonet, the statewide average rain total was 4.8 inches, 1.6 inches above normal and the 17th wettest April since records began in 1895. West central Oklahoma enjoyed its second wettest April on record with an average total of 7.6 inches, 5.2 inches above normal.