monthly climate summary

Many of Oklahoma’s most extreme rainfall events have occurred during the fall, the result of a rare conjunction of meteorological ingredients converging over the Southern Plains. Those ingredients – the remnants of a pacific tropical system, a stalled front, and abundant moisture from the Gulf of Mexico – came together late in the month to produce massive rainfall totals across south central Oklahoma. The Oklahoma Mesonet site at Fittstown recorded 14.2 inches of rain on Sept.

Autumnal temperatures, heavy rain, and drought reduction captured the Oklahoma weather headlines during August, although the blazing voice of summer was still heard on occasion. Drought shrank considerably in both coverage and intensity during the month thanks to some well-placed heavy rains. Wind, hail and flash flooding accompanied a somewhat unusual uptick in severe weather. Flash flooding necessitated water rescues in several cities, and a Main Street bridge was washed away in Norman. The severe weather culminated with two confirmed tornadoes in Mayes and Rogers counties on Aug.

Mother Nature threw Oklahoma a Hail Mary during the final week of July, offering drought-quenching rains and a glorious preview of fall. That brief seasonal transformation followed a dose of brutal summer weather that saw highs soar above 110 degrees and the heat index hit 120. The middle two weeks were especially fierce, culminating with record-breaking heat from the 19th through the 22nd. Temperatures reached 113 degrees at the Grandfield and Tipton Mesonet sites on both the 19th and 20th.

The Gulf of Mexico was in a giving mood throughout June, feeding a deep plume of tropical moisture to a succession of storm systems moving across Oklahoma. Not all areas were quite as fortunate as others, but a substantial portion of the state received significant, drought-reducing rainfall. The eastern Panhandle even got an unexpected boost from the remnants of hurricane Bud as it made its journey through the Gulf of California into the Northern Plains. The most prolific June rains fell from the eastern Panhandle through central and east central Oklahoma.

In defiance of spring, Mother Nature slipped right into summer during May, and broke a major record in doing so. Based on preliminary data from the Oklahoma Mesonet, the month finished as the warmest on record with a statewide average of 74.6 degrees, 6.4 degrees above normal. The previous record of 74 degrees was set back in 1962. This abrupt transition was especially jarring coming directly after the second coolest April on record. The heat was unkind to those battling severe drought conditions, but sporadic heavy rains did lend improvements to some.

Wildfires rolled across the Oklahoma prairie for two weeks in April, scorching hundreds of thousands of acres and placing entire towns in jeopardy. The fires came on the heels of more than six months of drought in which western Oklahoma received virtually no significant precipitation. Vegetation that had seen abundant growth during 2017 lay dormant or dead, awaiting a spark. Weather conditions coalesced on the 12th and 17th to produce fire danger labeled “historic.” As feared, fires roared to life on the 12th, driven to a frenzy on winds gusting to over 50 mph.

Drought continued to punish western Oklahoma throughout March, even as eastern sections saw additional relief. Similar to February, Interstate 44 served as a rough demarcation line between the above normal totals to the southeast and paltry offerings to the northwest. The news was dire for northwestern Oklahoma, where precipitation deficits that began in early October 2017 strengthened drought impacts. Fire danger rose to critical levels almost daily.

February rain records were shattered as a series of storm systems during the month’s final week brought snow, sleet and heavy rains to Oklahoma. The unsettled weather dumped a season’s worth of moisture over the southeastern half of the state and provided a brief brush with wintry weather. Kids across the state finally enjoyed a snow day or two as slippery travel shut down schools. The Oklahoma Mesonet site at Broken Bow led the state with an astounding 17.65 inches of rainfall, the highest total ever recorded in Oklahoma during February.

The dry weather that plagued Oklahoma through the final three months of 2017 showed no signs of letting up during the first month of 2018. The lack of precipitation was especially prominent across western Oklahoma where 19 of the Oklahoma Mesonet’s 120 stations received no precipitation for the month, and another 47 saw less than a quarter-inch. In some cases, the precipitation-free streak extended back to early October. The Mesonet sites at Woodward and Hooker had gone 113 consecutive days without a single drop of moisture by the end of January.

Oklahoma’s seemingly endless supply of mild weather came to an abrupt halt during the third week of December, ushering in a frigid end to a warm 2017. A bulge in the jet stream allowed frosty air to plunge southward and place most of the country into an arctic deep freeze. Oklahoma’s introduction to the cold air came on Dec. 21 and lasted through the end of the year. Highs in the 60s and even a few 70s were common during the first three weeks of December, topped by a high of 83 degrees at three Mesonet sites in southwest Oklahoma on the fourth.