July rainfall combined with June's historic rains to turn the two months into the second-wettest June and July on record in Indiana, according to the Indiana State Climate Office.
Rainfall during six weeks from about June 7 to July 21 totaled 15.09 inches, said the climate office, based in Purdue University's Department of Agronomy. The wettest June-July was in 1958, when 16.15 inches of rain fell in Indiana.
A preliminary statewide total of 6.05 inches of rain fell in Indiana in July, ranking the month as the seventh-wettest July since records began in 1895. The wettest July was in 1992 with 8.55 inches.
The hardest-hit areas in July were generally in two-county bands of Hendricks and Marion in central Indiana, and Clark and Jefferson in the southeast portion of the state. The heaviest reported rainfall was 17.65 inches in a Clark County monitoring station in Charlestown, noted Ken Scheeringa, associate state climatologist.
June set a record as the wettest June in Indiana at 9.04 inches. That exceeded the previous record of 8.13 inches in 1958.
A major cause of the six-week rain pattern was high pressure, anchored in the southeastern states, that deflected incoming storm systems to Indiana, the climate office reported. Storms originated in the Texas area on the west edge of the high-pressure system, containing large amounts of moisture from the Gulf of Mexico.
Since about July 21, however, upper atmosphere high pressure has expanded coast to coast across the southern states, cutting off the relentless moving of moisture from the Gulf.
"This new wind flow path has since returned Indiana to a likelihood of a more normal summer rainfall pattern," said State Climatologist Dev Niyogi.
The outlook for the remainder of August is for equal chances of below-, normal- or above-normal temperature and precipitation in Indiana. The early part of the month is expected to be much cooler and drier than normal, with a possible moderation in both temperature and precipitation in the middle and latter parts of the month.
A map showing July rainfall amounts throughout Indiana is available at http://www.iclimate.org/precip/images/2015/07/2015-07.gif.