September normally sees at least one or two decent cold fronts to whet the appetite for fall. Mother Nature had different plans this year, however, steering summer right past the beginning of autumn and giving Oklahoma its fourth warmest September since records began in 1895. The Panhandle experienced its warmest September on record, while the north central, southeast, and west central areas of the state had their second warmest. Tulsa ended with their second warmest September on record at 81.2 degrees, 8.2 degrees above normal. Oklahoma City’s 78.8 degrees earned them a ranking of seventh warmest at 4.9 degrees above normal. Gage suffered its warmest September since its records began, dating back to 1904. At least eight other NWS sites eclipsed their previous September monthly temperature records.
The statewide average temperature of 79.4 degrees – as observed by the Oklahoma Mesonet – was a whopping 7.1 degrees above normal. Only 1931’s 80.1 degrees, 1998’s 79.6 degrees, and 1939’s 79.5 degrees were higher. Triple-digit temperatures occurred as late as Sept. 27 with the Buffalo and Freedom Mesonet sites registering 101 and 100 degrees, respectively. The month’s highest temperature of 103 degrees occurred at Grandfield on the seventh. Twenty-eight readings of at least 100 degrees were reported by the Mesonet during the month. The month’s lowest reading was 48 degrees at Kenton on the 25th. The heat index was not as unbearable as it had been over the previous couple of months, but it did hit the century mark 596 times at the Mesonet’s 120 sites. A heat index of 106 degrees topped that category at six different sites. The first nine months of the year ended at 63.7 degrees, 0.3 degrees above normal to rank as the 50th warmest January-September on record.
Rains were both plentiful and scarce, depending upon location. The statewide average of 3.43 inches was a tenth of an inch below normal to rank as the 51st wettest September on record. Deficits of 2-4 inches were the rule across the northwest and parts of central and southeast Oklahoma. Meanwhile, surpluses of 2-5 inches occurred in the north central, northeast and southeast sections of the state. Parts of McCurtain County received more than 10 inches while the far northwest struggled to eclipse a half-inch. The Mesonet’s highest recorded total was 11.6 inches at Mt. Herman in McCurtain County. Freedom in Woodward County recorded a tenth of an inch to bring up the rear. The year continued on pace to finish as one of the top-10 wettest on record with a January-September statewide average of 37.01 inches, 8.62 inches above normal, the eighth wettest such period since records began in 1895.
Drought continued a slow decline after peaking in late August. By the end of September, drought had been reduced to less than 12% of the state according to the U.S. Drought Monitor, down from a high of 24% on August 20. Most of the drought was considered moderate in intensity, centered on far southwestern Oklahoma. There was a small area of severe drought in the far southwest that had been downgraded from extreme drought the previous week. The Drought Monitor’s intensity scale slides from moderate-severe-extreme-exceptional, with exceptional being the worst classification. Moderate drought increased slightly across the northwest in Ellis, Roger Mills and Woodward counties. Additionally, 16% of the state was considered in “abnormally dry” conditions, a precursor to drought intensification or an area recovering from drought but not yet back to normal.
The October temperature outlook from the Climate Prediction Center (CPC) indicates increased odds for above normal temperatures across the southeastern half of the United States, including Oklahoma. Those odds are greater across the southern two-thirds of the state. The October precipitation outlook shows increased odds for above normal precipitation across the northwestern one-third of Oklahoma, with better chances in the Panhandle and far northwest. CPC’s October drought outlook anticipates drought removal across the northwest and Panhandle, but persistence in southern Oklahoma.