A sprawling storm system is expected to take shape across the United States this week as moisture from Hurricane Polo moves inland and collides with a strong cold front, setting the stage for several days of heavy rain, flooding and potentially severe thunderstorms.
Meteorologist Max Schuster, host of the Max Velocity – Severe Weather Center YouTube channel, said the developing system could become one of the most widespread and disruptive storms the country has experienced in more than three months, with impacts stretching from the Southwest and Great Plains toward the Midwest, Ohio Valley and eventually the East Coast.
The storm will not be a simple one-day event, either. Schuster said some form of unsettled weather could remain in place for four or five days as tropical moisture is pulled deep into the country and interacts with a changing jet stream and an advancing cold front.
Hurricane Polo’s Moisture Moves Inland
One of the biggest ingredients behind the developing storm is Hurricane Polo, which Schuster said had reached Category 5 strength three separate times before beginning its move north toward Baja California.
Although Polo is expected to weaken considerably as it crosses Mexico, the meteorologist stressed that its leftover moisture will remain important. The system is forecast to move toward the Desert Southwest and Texas as a tropical depression around Tuesday and Wednesday, while its moisture spreads into the central and southern Plains.
That distinction matters because a weakening hurricane can still have a major influence hundreds of miles from where its circulation ultimately falls apart. In this case, Schuster expects the tropical moisture to become absorbed into the larger weather pattern, providing fuel for a much broader storm system.
Heavy rain is expected to become increasingly widespread across New Mexico and nearby areas by Wednesday morning, with eastern Arizona also facing the possibility of significant rainfall over a relatively short period.
Schuster said he believes at least a few flash flood emergencies could develop in New Mexico, describing the flooding threat there as potentially tremendous.
Another weakening Pacific system is also contributing moisture. According to Schuster, former Hurricane Odallas will help send additional moisture into parts of the Southwest, supporting showers and thunderstorms across the Four Corners region early in the week.
Severe Weather Could Develop Wednesday
By Wednesday afternoon and evening, Schuster expects the broader storm to begin organizing more aggressively over the southern Plains, particularly near the Texas Panhandle.
One concern is rapidly falling atmospheric pressure, which could create a strong pressure gradient and produce significant winds even outside thunderstorms. Schuster said the European weather model indicated gusts could potentially reach 60 to 70 mph in some areas simply because of the strengthening low-pressure system.
At the same time, enough atmospheric instability could develop for severe thunderstorms across parts of the Texas Panhandle and western Oklahoma.
Schuster said damaging winds would be one of the main concerns, although he also raised the possibility of tornadoes as the low-level jet strengthens and deeper moisture arrives.
That combination makes Wednesday particularly worth watching. A system with strong background winds, tropical moisture and possible severe storms can create several hazards at once, which makes forecasting the exact location of the greatest impact more complicated than simply following one line of thunderstorms.
The threat could continue into Thursday, when thunderstorms may stretch as far east as Illinois and Indiana, although Schuster expects the more concentrated storm activity to remain across Kansas, Oklahoma and Texas.
Isolated to scattered severe storms may again be possible, with damaging winds the primary threat and a smaller risk of tornadoes.
Schuster also warned that any tornadoes forming in such a moisture-rich environment could become rain-wrapped, making them harder to see.
Flooding May Be The Biggest Concern
Despite the potential for severe weather, Schuster repeatedly emphasized flooding as the most serious threat from the overall system.
Large amounts of tropical moisture are expected to flow into areas that could receive repeated rounds of rain, increasing the risk that rainfall accumulates faster than rivers, drainage systems and already saturated ground can handle it.
Some model projections shown by Schuster indicated widespread totals of roughly 1 to 4 inches, with substantially higher amounts possible in localized areas.
He said parts of the central United States could potentially see 5 to 10 inches of rain by the middle or latter part of the week, while sections of New Mexico and Colorado could receive more than 4 or 5 inches.
In mountainous terrain, that amount of rain creates another concern: mudslides. Schuster noted that the landscape in New Mexico makes flooding and slope failures particularly dangerous when rainfall totals climb sharply over a short period.
Different forecast models disagree somewhat on exactly where the heaviest rain will fall, which is fairly normal several days before a complex storm develops.
The European model was more aggressive with moisture remaining from Polo, while Schuster said the GFS model shifted some of the largest rainfall totals farther south, including a possible corridor of 4 to 8 inches from around Dallas toward San Antonio.
The precise placement may change, but both scenarios point toward an unusually wet pattern across a large portion of the country.
Storm Could Last Into The Weekend
Rather than quickly moving through, the system could remain active through Friday and the weekend.
Schuster said showers and thunderstorms may continue from Texas through the Ohio Valley on Friday, with the broader system eventually reaching the East Coast around Saturday and Sunday.
He described it as a much longer-lived storm than many of the systems seen across the country in recent months.
That prolonged duration is important because flooding often becomes more serious when several rounds of rain repeatedly cross the same locations. Even moderate rainfall can become problematic when the ground has little time to dry before another batch of storms arrives.
Schuster also pointed to a broad excessive rainfall threat extending through a large portion of the central and southwestern United States, with areas around Albuquerque, Amarillo and El Paso among those he said could face particularly significant rainfall.
He suggested that some places could approach 6 to 10 inches of rain depending on how the system evolves, though he emphasized that model details still need to be refined.
A Strong Cold Front Follows
Behind the rain and storms, a significant temperature change is expected.
Schuster said warmer and more humid air will surge northward across the Mississippi Valley and southern Plains around Wednesday and Thursday before a stronger cold front begins pushing through the central Plains.
By Friday, overnight temperatures could drop into the 40s and 50s across the Midwest, Great Lakes and portions of the central and northern Plains.
Cooler air is then expected to continue spreading south through the weekend and into the beginning of next week as the main storm system moves east.
Schuster said even Dallas could see overnight temperatures fall into the upper 50s or lower 60s around the beginning of next week.
Farther into early October, the forecast becomes less certain, although the European model showed a sizable area of colder air potentially remaining over parts of the country.
For now, the more immediate concern is the transition between unusually deep tropical moisture and the stronger cold front expected later this week.
Northeast Conditions Gradually Improve
While the developing central U.S. storm becomes the main focus, Schuster said the powerful coastal system affecting the Northeast should gradually weaken.
Rain will continue across parts of New England on Monday, generally becoming lighter to moderate, although isolated flooding could still occur.
Winds should also steadily weaken as the storm loses strength, with much calmer conditions expected by late Tuesday and Wednesday.
That improvement will come as attention shifts westward, where moisture left behind by the Pacific hurricanes begins combining with the larger atmospheric pattern.
Schuster characterized the incoming system as the most widespread and potentially impactful storm the country has experienced in several months.
The exact rainfall totals, severe-weather corridors and timing will continue to depend on how quickly Polo weakens and where its moisture ultimately travels, but the overall signal is unusually broad: a large section of the country could face several consecutive days of active weather before cooler air finally pushes in behind the storm.
Mark grew up in the heart of Texas, where tornadoes and extreme weather were a part of life. His early experiences sparked a fascination with emergency preparedness and homesteading. A father of three, Mark is dedicated to teaching families how to be self-sufficient, with a focus on food storage, DIY projects, and energy independence. His writing empowers everyday people to take small steps toward greater self-reliance without feeling overwhelmed.
