As per reports, thunderstorms, flash flooding, wildfire conditions, and extreme heat are forecast across multiple regions of the US on Tuesday (23 June), with several warnings and watches in effect.

Thunderstorm activity is forecast across a broad corridor extending from the Northeast (Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania) to the High Plains (eastern Colorado, western Kansas, Nebraska, Wyoming, parts of New Mexico, Texas). Rainfall and thunderstorms are expected to develop across portions of the Central and Eastern US throughout the day.

• Two primary areas are being monitored for severe weather and flash flooding potential. The first extends across the Mid-Atlantic (including Delaware, Maryland, Virginia, West Virginia, and Washington DC) from the Delmarva Peninsula to the Coastal Carolinas (North Carolina and South Carolina).
• The second covers portions of the Mid-Mississippi Valley (including Missouri, Illinois, Kentucky, Tennessee, and Arkansas) through the High Plains. Thunderstorm activity along the Eastern Seaboard is forecast to diminish by evening, while unsettled conditions are expected to persist overnight across the Plains.
• Additional rounds of thunderstorms are forecast across the Heartland (Kansas, Nebraska, Iowa, Missouri) and the Upper Midwest (Minnesota, Wisconsin, Michigan, Iowa, Illinois) through Thursday (25 June). Rainfall and thunderstorms are also forecast across portions of the Great Basin (Nevada, Utah, southern Idaho, and western Wyoming) and the Southwest (Arizona and New Mexico) during the week.
• Flood watches are in effect until 1100 hours local time (1500 hours UTC) on Tuesday (23 June) across portions of southwest Virginia and southern West Virginia. Affected areas include Buchanan and Dickenson counties in Virginia and Boone, Logan, McDowell, Mingo, Wyoming, Raleigh, Fayette, Nicholas, Webster, Pocahontas, and Randolph counties in West Virginia.
• A separate flood watch is in effect until 1100 hours local time (1500 hours UTC) on Tuesday (23 June) for Tazewell County in Virginia and Mercer, Summers, Monroe, and Greenbrier counties in West Virginia, where additional rainfall and thunderstorms may result in localized flooding.
• A flood watch is in effect from 1300 hours local time (1700 hours UTC) through the evening on Tuesday (23 June) across southeastern Virginia, including Chesapeake, Virginia Beach, Norfolk, Portsmouth, Suffolk, Hampton, Newport News, York, James City, Isle of Wight, and Surry. Rainfall rates may exceed two inches per hour, with localized totals of three to five inches possible.
• A flood watch is in effect through Tuesday (23 June) afternoon across portions of Arkansas, Louisiana, southeast Oklahoma, and northeast Texas. Affected areas include Columbia, Hempstead, Howard, Lafayette, Little River, Miller, Nevada, Sevier, and Union counties in Arkansas; Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto, Jackson, Lincoln, Ouachita, Red River, Union, Webster, and Winn parishes in Louisiana; McCurtain County in Oklahoma; and Bowie, Camp, Cass, Franklin, Harrison, Marion, Morris, Red River, Titus, Upshur, and Wood counties in Texas. Rainfall totals of two to four inches are expected, with isolated areas potentially receiving five to seven inches.
• Red Flag Warnings remain in effect from 1200 hours local time (1800 hours UTC) until 2000 hours local time (0200 hours UTC on 24 June) across parts of north-central Colorado, including South and Southeast Grand County, West Central and Southwest Boulder County, Gilpin County, Clear Creek County, Summit County, North and West Park County, West Jackson County, and West Grand County.
• Forecast conditions include west winds of 10-20 miles per hour with gusts reaching 30-35 miles per hour and relative humidity levels as low as nine to 13 percent. Fire Weather Watches remain in effect for portions of Grand County, Summit County, and Park County from Wednesday (24 June) morning through afternoon.
• Additional Red Flag Warnings are in effect from 1200 hours local time (1800 hours UTC) until 2100 hours local time (0300 hours UTC on 24 June) across portions of central and southern Colorado, including Fremont County, Canon City, Howard, Texas Creek, the Eastern San Juan Mountains, La Garita Mountains, Wolf Creek Pass, Creede, Lake County, Chaffee County, and the San Luis Valley.
• Fire Weather Watches are also in effect for portions of the Upper Arkansas River Valley and San Luis Valley from Wednesday (24 June) morning through evening. Forecast humidity values may fall to as low as five percent, accompanied by west winds of 10-20 miles per hour with gusts up to 35 miles per hour.
• Extreme heat is forecast to persist across the West (California, Oregon, Washington, Idaho, Nevada, Utah), Southwest (Arizona and New Mexico), and Southern Plains (Texas and Oklahoma) through at least Thursday (25 June).