Alert archive / Missouri / Heat Advisories in 2026

Heat Advisory 2, NWS St. Louis, MO

June 27, 202625 counties in Missouri; 14 counties in Illinois

NWS St. Louis, MO issued this heat advisory at Jun 27, 2026, 1:59 AM CDT for 25 counties in Missouri; 14 counties in Illinois. It took effect at Jun 28, 2026, 12:00 PM CDT. It was in force for 37 hr.

The area

The counties it named.

The facts

Issued: Jun 27, 2026, 1:59 AM CDT (06:59 UTC)
In effect from: Jun 28, 2026, 12:00 PM CDT
Expired: Jun 30, 2026, 1:20 AM CDT
In force: 37 hr
Issued by: NWS St. Louis, MO

All 39 counties

Adams County, IL, Bond County, IL, Brown County, IL, Calhoun County, IL, Clinton County, IL, Fayette County, IL, Greene County, IL, Jersey County, IL, Macoupin County, IL, Marion County, IL, Montgomery County, IL, Pike County, IL, Randolph County, IL, Washington County, IL, Audrain County, MO, Boone County, MO, Callaway County, MO, Cole County, MO, Crawford County, MO, Franklin County, MO, Gasconade County, MO, Iron County, MO, Knox County, MO, Lewis County, MO, Lincoln County, MO, Madison County, MO, Marion County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Osage County, MO, Pike County, MO, Ralls County, MO, Reynolds County, MO, Saint Francois County, MO, Sainte Genevieve County, MO, Shelby County, MO, Warren County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 27 km from the middle of the area, began a volume at 07:01 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 7.0 hours before the alert went out and 245 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1 J/kg
Mixed-layer CIN: -33 J/kg
Mixed-layer LCL: 567 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 148 m²/s²
0-3 km storm-relative helicity: 199 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this heat advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS St. Louis, MO wrote its last area forecast discussion before this heat advisory went out at Jun 26, 10:43 PM CDT, 3 hours 16 minutes earlier.

Area forecast discussion, Jun 26, 10:43 PM CDT, 3 hours 16 minutes before

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The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 27, 1:59 AM CDT	Extreme Heat Watch	LSX	Jefferson, Saint Charles, Saint Louis, City of Saint Louis	11 hr
Jun 27, 12:13 PM CDT	Areal Flood Advisory	LSX	Jefferson, Saint Louis, City of Saint Louis	3 hr
Jun 27, 1:03 PM CDT	Areal Flood Advisory	LSX	City of Saint Louis	3 hr
Jun 27, 1:15 PM CDT	Extreme Heat Warning	LSX	Audrain, Boone, Callaway, Cole, Crawford, Franklin and 23 more	7 days
Jun 27, 1:29 PM CDT	Areal Flood Advisory	LSX	Saint Charles, Saint Louis	3 hr
Jun 27, 4:48 PM CDT	Areal Flood Advisory	LSX	Lincoln, Montgomery, Warren	3 hr
Jun 27, 12:06 PM CDT	Areal Flood Advisory	LSX	Marion	53 min
Jun 27, 12:08 PM CDT	Areal Flood Advisory	LSX	Clinton, Saint Clair, Washington	3 hr
Jun 27, 12:59 PM CDT	Flash Flood Warning	LSX	Marion	4 hr
Jun 27, 1:24 PM CDT	Areal Flood Advisory	LSX	Bond, Fayette	3 hr

Nearby

Heat Advisories in Missouri, 2026 Heat Advisories in Illinois, 2026 Every heat advisory in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.