The August weather patterns that brought temperatures over 100 degrees for the first half of the month followed by much higher than average precipitation are caused by an atypical La Nina weather pattern.
Normally, a La Nina would bring warmer than normal temperatures but dryer then normal conditions.
“Typically we don’t see this much moisture with a La Nina,” said State Climatologist Mary Knapp.
Upper level steering currents move weather patterns through the area but when those currents didn’t move the storms, the area got a lot of rain in a localized area causing the big rain amounts.
Normally the rainfall amounts usually peak in June then drop off for several successive months through November.
The extreme heat in the first half of August is unusual but not unprecedented. For nine of the first 13 days of August the temperature got above 100 degrees in Pratt. The other part of the weather that was unusual was that the low temperatures never get below 70 degrees for the same time period. The low temperatures are a lot higher then usual.
Then the weather pattern shifted and after days of no moisture Pratt has received 6.97 inches of rain for just the month of August. In a normal year, August is one of the driest months and Pratt only averages 2.96 inches of rain.
Preston holds the highest August total this year with 8.5 inches of rain reported at a weather station near Preston. Cullison on the other hand has had 5.52 inches in August so rainfall amounts have varied across the county, Knapp said.
Those high rain totals fell in the right places in the county resulting in the Ninnescah River flooding in Pratt twice in just seven days.
On both those occasions, the Ninnescah got out of its banks in Lemon Park and rushing water reached from the riverbank to the base of the road the first time the river overflowed on August 16. Just a week later, following more local heavy rains, the river was out of its banks again and the water was even higher.
At the Pratt County Veterans Memorial Lake the water got so high it completely filled the spillway area and water touched the roadway between the Wildlife and Parks Headquarters and the lake.
Overall Pratt has recorded 21.84 inches of precipitation in 2010 and that is more than Pratt usually gets in an entire year. In 2009, Pratt got 19.65 inches of precipitation for the whole year so Pratt is well ahead of 2009 and still has four months to go, Knapp said.
