NWS heat advisories cover parts of 17 states on September 1, heat indices up to 43°C (110°F) forecast, U.S.

19 National Weather Service (NWS) forecast offices have issued Heat Advisories covering portions of Arkansas, Delaware, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Michigan, Mississippi, Missouri, New Jersey, Ohio, Oklahoma, Pennsylvania, Tennessee, and West Virginia on September 1.

Forecast heat indices ranged from approximately 37°C (99°F) in parts of northern Indiana and northwestern Ohio to 43.3°C (110°F) in parts of the Jackson, Mississippi, and Chicago forecast areas. Several central U.S. offices maintained Heat Advisories through September 3 or September 4, with Kansas City/Pleasant Hill, St. Louis, Paducah and Springfield among the offices carrying advisories through Friday.

Several multi-day products cited the duration of the heat and reduced overnight relief in addition to afternoon heat-index values. Kansas City/Pleasant Hill, Indianapolis, Louisville, Cleveland, Northern Indiana, Paducah and Springfield were among the offices referencing warm nighttime conditions or limited overnight cooling.

NWS offices repeatedly warned that high temperatures and humidity can cause heat illness and advised residents to reduce strenuous outdoor activity, remain hydrated, and use air-conditioned environments where available.

NWS Wilmington OH: east-central and southeast Indiana, northern Kentucky and central to southern Ohio

A Heat Advisory was in effect from 14:00 EDT (18:00 UTC) on September 1 until 20:00 EDT on September 3 (00:00 UTC on September 4) across portions of east-central and southeast Indiana, northeast and northern Kentucky, and central, south-central, southwest and west-central Ohio. NWS forecast heat-index values up to 38.9°C (102°F), including across the Cincinnati, Columbus and Dayton areas.

NWS Jackson MS: southeast Arkansas, northeast Louisiana and much of central and western Mississippi

NWS Jackson maintained a Heat Advisory from 11:00 CDT (16:00 UTC) until 19:00 CDT on September 1 (00:00 UTC on September 2) across southeast Arkansas, northeast Louisiana and central, north-central, northwest, south-central, southwest and west-central Mississippi. Heat-index values were forecast up to 43°C (110°F), among the highest values in the supplied compilation, and NWS included additional precautions for outdoor workers.

NWS Kansas City/Pleasant Hill MO: eastern Kansas and broad areas of northern and central Missouri

A multi-day Heat Advisory covered portions of east-central and northeast Kansas and central, north-central, northeast, northwest and west-central Missouri through 20:00 CDT on September 4 (01:00 UTC on September 5). Heat-index values were forecast up to 41°C (105°F), although NWS said that value might not be reached every day and cited the duration of the heat and limited overnight relief as reasons for maintaining the advisory.

NWS Des Moines IA: central and south-central Iowa

NWS Des Moines maintained a Heat Advisory for central and south-central Iowa, including the Des Moines metropolitan area, through 19:00 CDT on September 2 (00:00 UTC on September 3). Heat-index values were forecast at approximately 38–40°C (100–103°F) across Dallas, Polk, Jasper, Poweshiek, Madison, Warren, Marion, Mahaska and several counties farther south toward the Missouri border.

NWS Indianapolis IN: all of central Indiana

All of central Indiana was under a Heat Advisory from 14:00 EDT (18:00 UTC) on September 1 until 20:00 EDT on September 3 (00:00 UTC on September 4). Peak heat-index values were forecast up to 41°C (105°F) each afternoon, with NWS also citing limited overnight relief from the heat and humidity.

NWS St. Louis MO: south-central, southwest and west-central Illinois and central, east-central, northeast and southeast Missouri

NWS St. Louis maintained a broad Heat Advisory across south-central, southwest and west-central Illinois and central, east-central, northeast and southeast Missouri through 20:00 CDT on September 4 (01:00 UTC on September 5). Heat-index values across the general advisory area were forecast up to 41°C (105°F).

A separate advisory block covering Madison, Monroe and St. Clair counties in Illinois and Jefferson, St. Charles, St. Louis County and St. Louis City in Missouri carried forecast heat-index values up to 42°C (108°F) through the same Friday expiration time. NWS also provided cooling-center and energy-assistance information for the St. Louis metropolitan area.

NWS Lincoln IL: central, eastern and southeastern Illinois

NWS Lincoln maintained a Heat Advisory across central, east-central, southeast and west-central Illinois through 19:00 CDT on September 3 (00:00 UTC on September 4). Afternoon heat-index values were forecast up to 41°C (105°F), with the product stating that values would fall to roughly 24–26°C (mid-to-upper 70s°F) at night; the product did not separately identify the nighttime variable.

A second block covering Marshall, McLean, Woodford, Champaign, Edgar and Vermilion counties began at 13:00 CDT (18:00 UTC) on September 1 and continued through the same Thursday expiration time, also with heat-index values up to 41°C (105°F).

NWS Cleveland OH: north-central, northeast and northwest Ohio

A Heat Advisory covered parts of north-central, northeast and northwest Ohio from 14:00 EDT (18:00 UTC) on September 1 until 20:00 EDT on September 2 (00:00 UTC on September 3). Peak heat-index values were forecast around 36–39°C (upper 90s to lower 100s°F), while overnight lows were expected near 22–24°C (low-to-mid 70s°F). NWS said hot and humid conditions would continue Thursday and that portions of the advisory might need to be extended.

NWS Louisville KY: south-central Indiana and north-central, northwestern and south-central Kentucky

A Heat Advisory was in effect from 13:00 EDT / 12:00 CDT (17:00 UTC) on September 1 until 20:00 EDT / 19:00 CDT on September 3 (00:00 UTC on September 4). Heat-index values of 38–42°C (100–107°F) were forecast for at least three successive days across portions of south-central Indiana and north-central, northwest and south-central Kentucky, while nighttime temperatures were forecast near 22–24°C (low-to-mid 70s°F).

NWS Quad Cities IA IL: eastern Iowa, western Illinois and northeast Missouri

NWS Quad Cities maintained a Heat Advisory across portions of northwest and west-central Illinois, east-central and southeast Iowa and northeast Missouri through 19:00 CDT on September 3 (00:00 UTC on September 4). The main advisory area, including Iowa City, Davenport, Moline and Burlington, had forecast heat-index values up to 40°C (104°F).

Bureau and Putnam counties in Illinois entered the advisory at 13:00 CDT (18:00 UTC) on September 1, while Carroll and Whiteside counties in Illinois and Clinton County in Iowa were also covered through Thursday. Both blocks carried forecast heat-index values up to 38°C (101°F).

NWS Chicago IL: central, east-central, north-central and northeast Illinois and northwest Indiana

NWS Chicago issued Heat Advisories for two afternoon and evening periods across central, east-central, north-central and northeast Illinois and northwest Indiana. The first ran from 12:00 CDT / 13:00 EDT (17:00 UTC) until 21:00 CDT / 22:00 EDT on September 1 (02:00 UTC on September 2), followed by another period during the same local hours on September 2, ending at 02:00 UTC on September 3.

Forecast heat-index values ranged from 38–43°C (100–110°F). An expanded September 1 advisory included Boone, De Kalb, Lee, Ogle, Winnebago, central Cook, DuPage, Kane, Lake, McHenry and northern Cook counties, where NWS said morning showers and thunderstorms could prevent the hottest forecast temperatures from materializing.

NWS Mount Holly, NJ: Philadelphia region, northern Delaware and parts of New Jersey

A Heat Advisory covered New Castle County in Delaware; Mercer, Camden, Gloucester and northwestern Burlington counties in New Jersey; and Delaware, eastern Chester, eastern Montgomery, Lower Bucks and Philadelphia counties in Pennsylvania from 12:00 EDT (16:00 UTC) until 20:00 EDT on September 1 (00:00 UTC on September 2). Heat-index values up to 38°C (100°F) were forecast across the advisory area, including Philadelphia, Wilmington, Trenton and Camden.

NWS Northern Indiana: northern Indiana, northwest Ohio and southern Michigan

NWS Northern Indiana maintained a Heat Advisory across northern Indiana and northwest Ohio from 14:00 EDT / 13:00 CDT (18:00 UTC) on September 1 until 20:00 EDT / 19:00 CDT on September 2 (00:00 UTC on September 3). Heat-index values of 37–40°C (99–103°F) were forecast, with overnight lows near 22–24°C (low-to-mid 70s°F), while heat indices could approach 38°C (100°F) again Thursday afternoon.

The office also expanded the advisory into Branch, Cass, Hillsdale, northern and southern Berrien, and St. Joseph counties in Michigan for the same period. Heat-index values there were forecast up to 38°C (100°F), with similarly warm overnight conditions.

NWS Paducah KY: southern Illinois, southwest Indiana, western Kentucky and southeast Missouri

NWS Paducah maintained one of the latest-expiring Heat Advisories in the supplied compilation, covering portions of southern Illinois, southwest Indiana, western Kentucky and southeast Missouri through 20:00 CDT / 21:00 EDT on September 4 (01:00 UTC on September 5). Daily peak heat-index values were forecast at 38–42°C (100–108°F).

NWS said heat-index values above 38°C (100°F) might continue into Saturday. The office also said several record-warm overnight low temperatures in the mid-70s°F were possible during the week, but the advisory did not identify the stations or specific records involved.

NWS Charleston WV: northeast Kentucky, southeast Ohio and much of West Virginia

NWS Charleston placed portions of northeast Kentucky, southeast Ohio and central, northern, southern and western West Virginia under a Heat Advisory from 13:00 EDT (17:00 UTC) on September 1 until 20:00 EDT on September 2 (00:00 UTC on September 3). Heat-index values up to 40°C (103°F) were forecast, including across the Charleston and Huntington areas and communities near the Ohio and Kentucky borders.

NWS Little Rock AR: central, eastern, north-central, southeast and western Arkansas

A Heat Advisory covered portions of central, eastern, north-central, southeast and western Arkansas from 12:00 to 20:00 CDT on September 1 (17:00 UTC on September 1 to 01:00 UTC on September 2). Heat-index values up to 42°C (108°F) were forecast across the main advisory area, including Little Rock, North Little Rock, Pine Bluff, Conway and Russellville.

Garland and Hot Spring counties, including Hot Springs and Malvern, were added for the same advisory period and carried the same forecast maximum of 42°C (108°F).

NWS Tulsa OK: northeast Oklahoma and west-central Arkansas

NWS Tulsa maintained a Heat Advisory from 12:00 to 20:00 CDT on September 1 (17:00 UTC on September 1 to 01:00 UTC on September 2) across Mayes, Nowata, Rogers, southeast Osage, Tulsa, Wagoner and Washington counties in Oklahoma and southern Crawford, central and southern Franklin, and north and central Sebastian counties in Arkansas.

Heat-index values up to 42°C (107°F) were forecast. NWS said heat-related illness was possible, especially among people not acclimated to the conditions or performing strenuous activity.

NWS Memphis TN: eastern Arkansas, northern Mississippi, southeast Missouri and western Tennessee

NWS Memphis maintained a Heat Advisory from 12:00 to 20:00 CDT on September 1 (17:00 UTC on September 1 to 01:00 UTC on September 2) across portions of eastern Arkansas, northern Mississippi, southeast Missouri and western Tennessee. Heat-index values up to 41°C (106°F) were forecast across an area including the Memphis metropolitan region, Jonesboro, West Memphis, Dyersburg, Southaven, Tunica, Clarksdale, Kennett and Caruthersville.

NWS Springfield MO: southeast Kansas and central, east-central, south-central, southwest and west-central Missouri

NWS Springfield maintained a Heat Advisory across southeast Kansas and central, east-central, south-central, southwest and west-central Missouri through 20:00 CDT on September 4 (01:00 UTC on September 5). Forecast heat-index values were 38–41°C (100–105°F), with minimal overnight relief and temperatures around 24–26°C (mid-to-upper 70s°F).

The advisory included Springfield, Joplin, Branson, Rolla, West Plains, Lake of the Ozarks and communities extending westward into southeast Kansas.

References:

¹ Heat advisory – NWS – Accessed at 13:30 UTC on September 1, 2026