More than 15 million Americans face life-threatening rainfall this week as moisture from two Pacific hurricanes collides with a jet-stream dip across the central and southern United States.
Flood watches went up Tuesday morning across ten states after Hurricane Polo came ashore in Mexico on Monday and began feeding leftover moisture from Hurricane Odalys into a southward dip in the jet stream, according to AccuWeather reporting carried in national coverage.
The heaviest rain is aimed at Arizona, Colorado, New Mexico, Kansas, Oklahoma, and Texas, with watches also covering Utah, Nebraska, Missouri, and Iowa. Additional soaking of more than two inches could reach Arkansas, Illinois, Indiana, Michigan, and Wisconsin by Friday.
National Weather Service offices already posted flash flood warnings in Arizona and New Mexico on Tuesday. Soil across the Southwest was already saturated, raising the odds that washes, creeks, dirt roads, and underpasses would go under quickly.
Hurricane Polo made landfall near Loreto in Baja California Sur on Monday. Roads flooded there, and streets in Puerto San Carlos were reported submerged by Tuesday.
The New York Post reported Polo as a Category 3 storm with sustained winds near 115 mph as it closed on Baja California Sur, with 6 to 12 inches of rain expected in parts of the peninsula and a projected second landfall in southern or central Sonora before the system weakened.
Forecasters said Polo was expected to lose hurricane status before its remnants crossed into the U.S. Southwest, but the National Weather Service still allowed that the system could be a tropical storm as its eye neared the Texas border Tuesday night.
AccuWeather meteorologist Alex Duffus described the setup in plain terms.
"This rainfall event will essentially consist of a triple threat combination: moisture leftover from Odalys, moisture transported from Polo and the incoming trough shifting across the West."
He added:
"All pieces will work together to create a life-threatening rainfall event for some locations."
AccuWeather meteorologist Brandon Buckingham warned that the strongest bands could dump water faster than many drainage systems can handle.
"Rainfall rates within the most intense bouts of rainfall this week can reach 2-3 inches per hour, which can create a life-threatening situation,"
AccuWeather projected as much as eight inches this week in parts of Colorado, Iowa, Kansas, Missouri, Nebraska, New Mexico, Oklahoma, and Texas. The weather service flagged a worst-case scenario of up to 18 inches in isolated spots.
Six states sat in a Moderate Risk zone for excessive rainfall on Tuesday: Arizona, New Mexico, Texas, Oklahoma, Colorado, and Kansas. Heaviest downpours were expected to shift into central Texas, Oklahoma, and Kansas on Wednesday, then into parts of Arkansas and Missouri on Thursday.
AccuWeather Chief Meteorologist Jonathan Porter put the New Mexico threat in sharp relief.
"In some places, especially in New Mexico, this may be the most dangerous flash flooding risk in the last five years or more, underscoring the importance of watching for and avoiding rapidly rising water."
Forecasters said the greatest risk of widespread property damage and injuries stretched across New Mexico and central Texas. Damaging wind gusts up to 60 mph and isolated tornadoes were also possible as the remnants moved through the South.
The National Weather Service kept the public guidance direct. Flooding of washes and creeks was expected. Some dirt roads would turn muddy and impassable. Paved roads and underpasses could flood as well.
NWS repeated the line that still saves lives every storm season:
"Turn around, don't drown when encountering flooded roads. Most flood deaths occur in vehicles."
That warning matters because colder air was pushing the jet stream south and carrying the moisture east toward the Midwest and Great Lakes. The rain shield was forecast to stretch from the Southwest toward those regions through the week, not dump everything in one afternoon and leave.
Travel trouble showed up early at Phoenix Sky Harbor International Airport. As of 11 a.m. ET, flights were delayed by an average of 37 minutes. The airport issued a ground delay for thunderstorms expected to run until at least 4 p.m. ET.
For a national traveler, that is the first practical hit: wet runways, stacked arrivals, and a system still feeding rain into the desert Southwest while the larger moisture plume marches toward the Plains.
Monday brought Polo’s landfall in Baja. Tuesday brought the watches, the Arizona and New Mexico flash flood warnings, and the first heavy rain focus on the six-state Moderate Risk corridor. Wednesday favors central Texas, Oklahoma, and Kansas. Thursday favors Arkansas and Missouri. By Friday, AccuWeather still saw more than two inches possible as far as Illinois, Indiana, Michigan, and Wisconsin.
No U.S. injury or death totals were reported in the initial round of coverage. The danger described so far is forecast risk, flooded Mexican towns near landfall, and the familiar American pattern of motorists underestimating water over the road.
When meteorologists stack leftover hurricane moisture, a fresh Pacific system, and a jet-stream dip over already wet ground, the smart move is the old one: watch the rises, skip the flooded crossing, and treat the next few days as a serious weather week, not a light rain delay.
