Excessive Heat in Sullivan, Indiana

Criteria was reached from maximum heat index values reaching 110 degrees on June 14th over all but far eastern portions of Sullivan County. Heat index values are estimated from combination of observed maximum temperature of 98 degrees at Farmersburg TV-2 station and estimated dewpoints from proximity to nearby HUF ASOS.

Following a northward-progressing warm frontal zone, a strong, broad, subtropical upper-level ridge built over central Indiana by June 14th. Associated heat and at times record-high dewpoints (for June) then lasted for several days across the region. Morning lows were mainly in the mid-70s to low 80s, while afternoon highs in the mid-90s were common; dewpoints climbed into the upper 70s on June 14th, and stayed in the mid-70s through June 16th. Excessive Heat criteria of 110 degree or higher heat indices was reached during the afternoon and/or late day hours of June 14th, in 9 of central Indiana's 39 zones between far southwestern counties, southeastern portions of the Indianapolis Metro area, and two north-central counties.