Excessive Heat — Cape Girardeau, Missouri

2025-07-19 to 2025-07-30 · Cape Girardeau, Missouri

Event narrative

Heat continued from mid-July. Heat indices only reached heat advisory duration criteria July 26th and 27th.

Wider weather episode

An extended heat wave across the Quad State region occurred from mid to late July. On the synoptic scale, at 500mb, a 594dam ridge was present across the Southeast U.S., with the ridge building northward to include the Ohio Valley and Great Lakes by July 22nd-23rd. The Quad State was initially on the edge of the ridge from the 17th-20th, resulting in greater coverage of showers and thunderstorms. Convection coverage became more isolated the 22nd-25th as the ridge strengthened over the Ohio Valley. The ridge relaxed slightly on the 26th-27th, before the worst of the heat arrived on the 28th-29th. A cold front moving through on the 31st allowed for a much cooler and drier airmass to move across the region.

For Southeast Missouri, high temperatures in the low to mid 90s combined with very high humidity (dew points in the mid 70s to low 80s) produced heat index values routinely in the 102 to 112 range from July 19th through the 30th. Some relief came during the northern portions of Southeast Missouri on the 21st due to showers and increased cloud cover. As the ridge amplified and shower activity decreased, Southeast Missouri became covered in widespread heat indices of 105-115 from the 22nd-25th, with localized higher readings. Slight decreases in heat indices occurred on the 26th-27th as more clouds were around, followed by the most oppressive heat with widespread heat indices of 110-120 with localized higher readings on the 28th-29th. The heat wave continued through the 30th, then a cold front moving south through the region brought relief to close out the month. Heat Advisories or Extreme Heat Warnings were in effect for portions of the Quad State for 15 consecutive days.

Sikeston, MO reached a heat index of 110+ for 10 consecutive days and exceeded 105 degrees every day during the 15 day heat wave. Cape Girardeau, MO broke their all-time record for consecutive days with a 75 degree dew point with 26 straight days from July 6-31, while 49 consecutive days reaching a 70 degree dew point was one shy of the record. Cape Girardeau observed 10 straight days of a heat index of at least 105 from July 16th-25th, tying their longest streak in 1999, while reaching 100 degrees 16 straight days was one shy of their record (heat index records date back to 1996 for Cape Girardeau). Poplar Bluff, MO experienced 25 consecutive days with a 75 degree dew point from July 6-30, which is tied for the 3rd longest streak on record, while 51 consecutive days with a dew point of 70 was one shy of the record. Poplar Bluff observed 9 consecutive days reaching a heat index of at least 105 degrees from July 17th-26th, which was three days shy of the all-time longest streak, while their 15-day streak of reaching 100 degrees is tied for second longest (heat index records date back to 1997 for Poplar Bluff). The highest heat index in Southeast Missouri for the late July heatwave was 122 at the Big Spring RAWS site in Carter County on the 22nd.

Source: NOAA Storm Events Database, event_id 1290647. Narrative written by the NWS forecast office that issued the report.