Heat in Minnesota, July 29 to 30, 1999

Less than one week after the first heat wave, central and south central Minnesota were belted with even greater heat, especially on the 30th. The morning of the 29th started with lows in the 70s and dewpoints in the middle 60s to middle 70s, producing heat indices from 70 to 85. With afternoon highs well into the 90s, and dewpoints ranging from the middle 60s to upper 70s, heat indices climbed to the 95 to 114 range. Southern Minnesota bore the brunt of the heat this day with numerous triple digit indices. Faribault recorded the highest index at 114, with 113 at St. James, 111 at Redwood Falls, and 110 at Appleton and New Ulm. Though farther north, the central Minnesota cities of Mora and Little Falls still registered an index in the middle 90s.A muggy night pervaded southern Minnesota, as some locations saw their low temperature remain around 80. Combined with dewpoints in the 70s, the heat index hovered in the lower and middle 80s at locations such as Minneapolis/St. Paul, Redwood Falls and Albert Lea. Central Minnesota locations had an overnight heat index in the 70s.By 0900 CST on the 30th, the heat index had already climbed past 100 at Minneapolis/St. Paul and many other locales. High temperatures soared into the middle and upper 90s. Dewpoints neared 80, and some spots even exceeded 80. At 0755 CST, Minneapolis/St. Paul (MSP) tied an alltime record high dewpoint of 81 (equalling a mark set in 1995). Thus the heat index exceeded 110 in most areas. The highest reading was 122 at Faribault. A sampling of the heat index at other locations revealed 119 at Mora and Eden Prairie (Flying Cloud Airport/FCM), 116 at Redwood Falls, 115 at St. Cloud, and 113 at Glenwood. A cold front moved in later on the 30th, bringing severe thunderstorms and an end to the heat wave.