12 May 2022 | 03:47 PM UTC
US, Canada: Adverse weather forecast across the South, Ohio Valley, and North Central regions, US and south-central Canada through at least May 15 /update 2
Adverse weather forecast across the South, Ohio Valley, and North Central regions, US and south-central Canada through at least May 15.
Event
Severe weather is forecast across portions of the South, Ohio Valley, and North Central regions in the US and south-central Canada through at least May 15. Thunderstorms will likely be accompanied by heavy rainfall, strong winds, hail storms, and possible tornadoes.
Government Advisories
As of late May 11, the National Weather Service (NWS) has issued flood watches and warnings across parts of eastern North Dakota and northern Minnesota. Authorities will likely issue watches and warnings over the coming hours and days as the storm progresses.
The NWS's Storm Prediction Center has warned of a "Moderate Risk" (Level 4 on a five-tier scale)of severe thunderstorms over portions of eastern South Dakota, western Minnesota, and southeastern North Dakota May 12-13. There is an "Enhanced Risk" (Level 3) of severe thunderstorms for surrounding areas of southeastern North Dakota, eastern South Dakota, western and central Minnesota, northwestern Iowa, western Nebraska, and into far northern Kentucky. There is also a "Slight Risk" (Level 2) of severe thunderstorms from western Upper Michigan to northeastern Oklahoma and northwestern Arkansas May 13-14 and across parts of central and eastern Kansas, northern and eastern Oklahoma, southwestern Missouri, and far northwestern Arkansas May 14-15.
A "Moderate Risk" (Level 4) of severe thunderstorms indicates a potential for widespread severe weather with several thunderstorms and/or tornadoes possible, some of which may be intense. 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.
The NWS's Weather Prediction Center has warned of a "Slight Risk" (Level 2 on a four tier-scale) of excessive rainfall for parts of northeastern Montana, northwestern and eastern North Dakota, eastern South Dakota, and much of Minnesota May 12-13.
Environment Canada has issued red rainfall warnings across western Ontario and southeastern Saskatchewan provinces and special weather statements for heavy rainfall with possible embedded thunderstorms across parts of southern Manitoba, western and central Ontario, and southeastern Saskatchewan.
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, as well as 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 in the 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.
