The first half of June continued our recent trend of cool, rainy weather, but in the last half of the month, the weather finally surrendered to the calendar and the heat was on.
Our hottest high temperature was 97 on the 16th. Our coolest low was 60. Our average monthly temperature during June was 81, which was 1 degree warmer than normal.
Briefly, some unfinished business: In the May climate summary, which was closed several days before the end of the month, I predicted heavy rains “of 2 inches or more” over Memorial weekend would push Denton County’s monthly rainfall total over our May average of about 4 inches. That was quite the understatement.
The last few days of May saw nearly 4.75 inches of rain, which pushed May’s total to 7.57 inches. May was also the third consecutive month with rainfall totals sharply above normal. March was +2.3″, April was +2.4″, and May +2.4″.
June kept the streak alive for a fourth month with 4.3″, which was about half an inch above normal for the month. The reason for the rain was a relatively rare occurrence known as a “TUTT Low.” Unlike the mid-latitude storm systems that normally cross Texas from west to east, a TUTT is an upper level trough of low pressure that forms high over the Tropics, hence the name, “Tropical Upper Tropospheric Trough.”
In this case, the actual low pressure “trough” of the system which originated in the Atlantic, became cut off from upper level winds as it exited the Gulf of Mexico and wrapped itself up into a semi-stationary low pressure system over Texas, becoming a “TUTT Low.” TUTTs bear some resemblance to Easterly waves, Tropical storms and Hurricanes, but they form in the upper atmosphere, produce less severe weather and can last indefinitely over land.
Year-in and year-out, heat is the #1 cause of weather-related fatalities. Looking ahead, there’s no reason to expect any more cool, rainy weather. Not only are we into July, but surface temperatures in the Pacific continue to cool and have officially ended the El Nino phase of the Southern Oscillation. Odds favor continuing the cooling cycle through neutral conditions into a La Nina phase. National Weather Service Climatologist Victor Murphy recently noted that the 8 DFW summers with the most 100-degree temperatures occurred during either neutral or La Nina conditions.
It was nice while it lasted.
Brad Barton is Chief Meteorologist for WBAP820/570KLIF/99.5 “The Wolf.” He also serves as Home field Meteorologist for the Texas Rangers Baseball Club. Paul Ruekberg of NewsWatch Dallas contributed to this report.