The combination of a strong upper-level high pressure over the central United States and moist southwest winds resulted in hot and humid conditions across the Mid-Atlantic that produced excessive heat conditions.

Excessive Heat in PRINCE GEORGES, MARYLAND
From 28-JUL-23 12:30:00 to 28-JUL-23 17:30:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: RAWS

The RAWS station at Cedarville State Forest, CVLM2, measured heat indices as high as 114F. Numerous other mesonets across Prince George's County measured heat indices in excess of 110F.

Excessive Heat in CENTRAL AND SOUTHEAST MONTGOMERY, MARYLAND
From 28-JUL-23 12:30:00 to 28-JUL-23 16:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A Maryland Department of Transportation mesonet, MD-001, located at the intersection of Interstate 270 and Interstate 370, measured heat indices as high as 111F. Several other mesonets across Central and Southeastern Montgomery County measured peak heat indices in excess of 110F.

Excessive Heat in CENTRAL AND SOUTHEAST HOWARD, MARYLAND
From 28-JUL-23 12:00:00 to 28-JUL-23 16:30:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A mesonet station in Columbia, Maryland, DW1546, measured heat indices as high as 113F. Several other mesonets across Central and Southeast Howard County measured peak heat indices in excess of 110F.

Excessive Heat in SOUTHEAST HARFORD, MARYLAND
From 28-JUL-23 13:00:00 to 28-JUL-23 17:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The RAWS station at Susquehanna State Park, SSQME, measured heat indices as high as 110F. Several other mesonets across Southeast Harford County measured peak heat indices at or in excess of 110F.

Excessive Heat in CECIL, MARYLAND
From 28-JUL-23 13:00:00 to 28-JUL-23 17:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Several mesonset stations across Cecil County measured heat indices above 110F for several hours.

Excessive Heat in SOUTHERN BALTIMORE, MARYLAND
From 28-JUL-23 13:00:00 to 28-JUL-23 17:30:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The ASOS at Baltimore Inner Harbor, KDMH, measured peak heat indices as high as 112F. Several other mesonets across southern Baltimore County measured heat indices in excess of 110F.

Excessive Heat in ST. MARY'S, MARYLAND
From 28-JUL-23 12:00:00 to 28-JUL-23 17:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

The AWOS at Patuxent River NAS, KNHK, measured heat indices as high as 111F. Numerous other mesonets across St. Mary's County measured peak heat indices in excess of 110F.

Excessive Heat in CHARLES, MARYLAND
From 28-JUL-23 13:00:00 to 28-JUL-23 17:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A Maryland Department of Transportation mesonet, MD-105, located at the intersection of Maryland Route 344 and Maryland Route 244 measured heat indices as high as 114F. Numerous other mesonets across Charles County measured peak heat indices in excess of 110F.

Excessive Heat in CALVERT, MARYLAND
From 28-JUL-23 13:30:00 to 28-JUL-23 18:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A Maryland Department of Transportation mesonet, MD-147, located at the intersection of Maryland Route 4 and Thomas Johnson Bridge, measured heat indices as high as 113F. Several other mesonets across Calvert County measured peak heat indices in excess of 110F.

Excessive Heat in ANNE ARUNDEL, MARYLAND
From 28-JUL-23 13:00:00 to 28-JUL-23 17:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The ASOS at Baltimore-Washington International Airport, KBWI, measured heat indices as high as 113F. Numerous other mesonets across Anne Arundel County measured heat indices in excess of 110F.

Excessive Heat in WASHINGTON, MARYLAND
From 28-JUL-23 13:00:00 to 28-JUL-23 17:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The ASOS at Hagerstown Regional Airport, KHGR, measured heat indices as high as 106F. Numerous other mesonets across Washington County measured heat indices in excess of 105F.