WASHINGTON, DC — A sprawling storm system is moving across the country and is set to affect more than 35 states with severe thunderstorms, heavy rain and damaging wind gusts. It is already producing hazardous conditions in the Southwest and Four Corners region, where flooding has prompted evacuations and raised concerns about fast-rising water. The same system will then sweep east, bringing a new round of severe weather to the Plains, before expanding into the Midwest and eventually the Northeast later this week.
Forecasters say the storm is drawing deep tropical moisture north from the Pacific, which is helping fuel repeated rounds of rain. As it advances, a strengthening low-pressure area and cold front are expected to bring additional impacts, including strong winds, heavy mountain snow and travel disruptions across several regions.
Flooding and evacuations continue across Arizona and the Four Corners
The most urgent problems right now are concentrated in Arizona, southern Utah, northwest New Mexico and southwest Colorado. Flooding in those areas has already turned dangerous enough to trigger mandatory evacuations in parts of the region as water levels rise around homes, roads and businesses.
In Sedona, Arizona, officials urged some residents to leave as Oak Creek continued to climb. The creek reached a record level, adding to fears of significant flooding. The Weather Prediction Center has placed a Level 3 out of 4 flash flood risk over more than 65,000 square miles, an area roughly the size of Washington state, with nearly all of central and northern Arizona inside the threat zone.
That risk area includes more than four million people. The heaviest rain is expected along and north of the Mogollon Rim, including Flagstaff and the surrounding high country, where runoff and rising water remain major concerns through Monday morning.
Arizona and Colorado face dangerous rainfall totals and river threats
Rainfall totals in the Southwest could become extreme in a short period. The FOX Forecast Center said widespread amounts of 3 to 5 inches are possible, with isolated spots approaching 6 inches. Flagstaff has already recorded 5.69 inches of rain in October and is expected to pick up more as the storm lingers.
In southwest Colorado, the situation is also serious near the San Juan Mountains. Town officials in Pagosa Springs issued mandatory evacuations for homes and properties on Saturday. A Particularly Dangerous Situation Flood Warning is in effect for the San Juan River near town, where the river is forecast to rise to about 19 to 20 feet late Sunday night into early Monday morning.
Officials in Pagosa Springs also warned residents that sewage is being discharged into the San Juan River and said people should stay away from the water while conditions are monitored. Heavy runoff is expected to keep rivers and drainage systems elevated into early next week.
Heavy wet snow and 50 mph winds will complicate mountain travel
Flooding is not the only hazard in the West. Colder air moving into the region will bring snow to higher elevations, creating a second layer of danger for mountain communities and travelers. The highest elevations of the San Juan, Sawatch, Wasatch and Uinta ranges could see more than a foot of wet, heavy snow.
Southwest Colorado’s mountain passes may receive 12 to 18 inches, while 4 to 10 inches is possible across other high-elevation areas. That kind of snow can bring down tree limbs, disrupt power and make roads difficult to use. Combined with the flooding, it may leave some areas hard to reach.
Strong winds will make conditions worse. Southwesterly gusts could reach 30 to 50 mph Sunday across mountain ridges, then shift to the northwest Monday with similar speeds possible. Blowing snow could cut visibility on mountain roads, while blowing dust may affect parts of the desert Southwest.
Severe thunderstorms are expected from Kansas to north Texas Monday night
As the storm moves east of the Rockies on Monday, it will trigger a fresh severe-weather threat in the Central and Southern Plains. Forecasters expect thunderstorms to develop Monday afternoon and evening across parts of Kansas, Oklahoma and north Texas as a cold front and dryline move through the region.
Warm, humid air ahead of the system will feed the storms, while strong winds will support more organized development. The FOX Forecast Center says the storms could produce large hail, damaging wind gusts and a few tornadoes. The Storm Prediction Center has issued a Level 2 out of 5 severe storm risk for parts of south-central and eastern Kansas, western and central Oklahoma and north Texas.
The storms are expected to organize into a line and track east across Oklahoma, Kansas and north Texas by Monday evening and into the overnight hours. Straight-line winds are expected to be the main threat, although tornadoes remain possible.
Midweek rain and wind will stretch from the Midwest to the Northeast
By Tuesday, the cold front will move into the Deep South and bring damaging wind potential to Louisiana, Mississippi, Arkansas and Alabama. On Wednesday, the system is expected to push into the Upper Midwest, where gusty winds and periods of heavy rain will continue the disruption.
Wind gusts of 40 to 50 mph are possible from eastern Kansas and Nebraska through Iowa, Minnesota and Wisconsin. Forecasters say those winds could make travel hazardous and lead to delays. Heavy rain is also expected to spread across Texas and Oklahoma through Missouri, Iowa, Nebraska, Illinois, Minnesota and Wisconsin, with many locations getting 1 to 2 inches or more.
The Weather Prediction Center has put those areas under a Level 1 out of 4 excessive rainfall risk across a dozen states. Widespread flooding is not expected, but localized flooding could affect cities including Omaha, Des Moines and Minneapolis.
Rain may linger into Friday and early Saturday in the Northeast
The storm is expected to continue east into the Great Lakes and Mid-Atlantic by midweek before reaching the Northeast, where heavy rain is likely. Rain should begin spreading into the Ohio Valley on Wednesday and move toward the I-95 corridor around Thursday or Friday.
Forecasters also say the system could slow near the Great Lakes if a secondary low-pressure area develops or strengthens along the East Coast. That setup could pull moisture farther inland and extend the rain through Friday night and into early Saturday.
Widespread rainfall totals of more than an inch are possible across the Northeast, with localized amounts approaching 2 inches from central Pennsylvania and Maryland through the New York City area and southern New England. Those downpours could lead to minor flooding as the system finally moves out.