04 Jul 2022 | 09:46 AM UTC
US: Adverse weather forecast across north-central and eastern regions through at least July 6
Severe weather forecast across parts of the north-central and eastern US through at least July 6. Tornadoes and flooding possible.
Event
Rounds of severe thunderstorms are forecast across parts of the north-central and eastern US through at least July 6. Storms impacting the northern plains overnight July 3-early July 4 are expected to spread southeastward towards the Great Lakes July 4 and onto the Ohio Valley and the central Appalachians July 5. Further rounds of storms are expected to follow roughly the same paths from the northern plains eastward as far as the Mid-Atlantic in the coming days. Thunderstorms will likely be accompanied by heavy rainfall, strong winds, hail storms, and possible tornadoes. Heavy rainfall may result in floods and flash floods, especially over low-lying areas or areas close to water bodies. Strong winds associated with the storms of up to 126 kph (78 mph) have been recorded in parts of Montana late July 3 and hail storms in parts of South Dakota.
Government Advisories
As of early July 4, the National Weather Service (NWS) has issued flash flood and flood warnings and severe thunderstorms watches over parts of central and eastern South Dakota. Flood watches have been issued for parts of southern and southeastern North Dakota and western Minnesota.
The National Weather Service's (NWS) Storm Prediction Center has warned of an "Enhanced Risk" (Level 3) of severe thunderstorms early July 4 for parts of eastern Montana and western North Dakota. There is a "Slight Risk" (Level 2) of severe thunderstorms for the same period for areas surrounding the Enhanced Risk area, including parts of central and eastern Montana, western and southern North Dakota, much of South Dakota, much of Nebraska, far northern Kansas, and far western Minnesota. A Slight Risk continues over much of the affected areas at various times over the coming days.
Severe storms in the "Enhanced Risk" (Level 3) regions are forecast to be more numerous, persistent, and widespread than those in the region where a "Slight Risk" (Level 2) has been issued. Storms in the Slight Risk regions are not forecast to be widespread or long-lived. Isolated intense storms are possible, which may contain hail, damaging winds, and a few tornadoes; however, widespread damage is unlikely.
NWS's Weather Prediction Center has warned of a "Slight Risk" (Level 2 on a four-tier scale) of excessive rainfall over parts of eastern Montana, central and southern North Dakota, far western Minnesota, and far northeastern South Dakota early July 4. There is also a "Slight Risk" of excessive rainfall over parts of central and southern Wisconsin, far southeastern Minnesota, northeastern Iowa, far northern Illinois, and far western Michigan July 4-5 and for much of West Virginia, southeastern Ohio, southwestern Pennsylvania, far northwestern Maryland, northern and western Virginia, and far eastern Kentucky July 5-6.
Officials could update and possibly extend the coverage of weather alerts over the coming days.
Hazardous Conditions
Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rainfall has saturated the soil.
Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days and tornado warnings advising the public to shelter in place. Disruptions to electricity and telecommunications services are possible where severe weather impacts utility networks.
Transport
The severe weather will likely contribute to transport disruptions throughout the region. Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.
Severe weather could also trigger flight delays and cancellations at airports across the affected region. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas that see heavy rainfall and potential track inundation.
Localized business disruptions may occur in flood- or tornado-hit areas; some businesses might not operate at full capacity because of damage to facilities, possible evacuations, and some employees' inability to reach work sites.
Advice
Monitor local media for weather updates and related advisories. Confirm all transport reservations and business appointments before travel. Make allowances for localized travel delays and potential supply chain disruptions where flooding has been forecast. Do not drive on flooded roads. Review contingency plans and be prepared to move quickly to shelter if tornado warnings are issued. Charge battery-powered devices in the case of prolonged electricity outages.
