Hurricane Polo Remnants Bring Major Flooding Threat
On our storm map today, the primary focus is on the potential for significant and potentially severe flooding across the Desert Southwest and into the Central Plains as the remnants of Hurricane Polo move northward.
Polo will come up through Baja California today, with its remnants and associated tropical moisture spreading into Arizona and New Mexico and eventually into portions of Colorado and Kansas by tomorrow. Rain is already developing across parts of the Southwest, and additional precipitation will become more widespread today.
Desert Southwest Flooding
The concern is that some of this rainfall could become very heavy, with localized rainfall totals potentially reaching four to five inches in the hardest-hit areas. For the Desert Southwest, that is an enormous amount of rainfall, particularly when it occurs over a relatively short period of time.
Heavy rain is already occurring across portions of Arizona, particularly from the Phoenix area eastward, and additional rounds of thunderstorms and heavy rainfall are expected today. This could lead to rapid runoff, flash flooding, and rising water levels in normally dry washes and streams.
The flooding threat will not be limited to Arizona and New Mexico. Areas farther north, including southern Utah, could also experience flooding as the tropical moisture plume expands northward.
Heavy Rain Spreads Into the Plains
As the remnants of Polo continue moving north and east, the heavy rain will spread out of the Southwest and into the Plains.
Flooding problems could develop across Kansas and Colorado, with the threat eventually expanding into Nebraska, Iowa, Minnesota, and Wisconsin as the system continues to track northeastward.
Some areas could receive multiple rounds of rainfall, increasing the potential for significant runoff and flooding. Locations that experience repeated thunderstorms or slow-moving bands of heavy rain will be particularly vulnerable.
The Bottom Line
This is shaping up to be a major moisture event, with the remnants of Hurricane Polo transporting tropical moisture from Baja California northward through the Southwest and into the Plains and Upper Midwest.
The greatest immediate concern is Arizona and New Mexico, where heavy rainfall on top of already-wet areas could produce serious flash flooding. But the threat will expand rapidly, eventually reaching Colorado, Kansas, Nebraska, Iowa, Minnesota, and Wisconsin.
With some locations potentially receiving four to five inches of rain, this is a storm system that could produce significant flooding and dangerous conditions across a large portion of the country.