Tropical moisture brings flash-flood risk to Southwest
Tropical moisture is expected to bring widespread showers and thunderstorms across Southern Nevada through Tuesday, with the greatest flash-flood risk in Mohave County, Arizona. Heavy rain, lightning, strong gusts and hazardous boating conditions are the main concerns.
By DoomRadar · Published on DoomRadar . Updated .
Based on two sources with available article excerpts. Source-linked claims are not independent confirmation.
Event date: The National Weather Service forecast widespread showers and thunderstorms through Tuesday, with some risks persisting beyond the initial system's eastward movement. [1]
What happened
The National Weather Service in Las Vegas forecast widespread showers and thunderstorms across Southern Nevada through Tuesday. The greatest flash-flood danger was identified in Mohave County, Arizona, with lesser chances across Clark and Lincoln counties in Nevada and eastern San Bernardino County, California. [1]
References for this detail (1)
- Tropical moisture to bring storms, flash flood risk to Las Vegas area through Tuesday - Las Vegas Sun Newslasvegassun.com · Article published: Sep 28, 2026, 3:00 PM UTC
The system was expected to move east on Tuesday, but the forecast said minor flash-flood, thunderstorm and heavy-rain risks would persist across the eastern part of the forecast area. This describes a continuing weather threat rather than a confirmed flood in every location. [1]
References for this detail (1)
- Tropical moisture to bring storms, flash flood risk to Las Vegas area through Tuesday - Las Vegas Sun Newslasvegassun.com · Article published: Sep 28, 2026, 3:00 PM UTC
The Weather Prediction Center placed the chance of flash flooding within 25 miles of a point in the highest-risk area at 40% or higher. Mohave County and eastern portions of Clark and Lincoln counties, along with eastern San Bernardino County, were identified as the areas with the greatest excessive-rainfall chance. [1]
References for this detail (1)
- Tropical moisture to bring storms, flash flood risk to Las Vegas area through Tuesday - Las Vegas Sun Newslasvegassun.com · Article published: Sep 28, 2026, 3:00 PM UTC
The forecast gave a 10% chance of rainfall exceeding 3.3 inches in Colorado City, 2 inches in Kingman, 1.2 inches in Lake Havasu City and 0.9 inches in Las Vegas on Monday. Tuesday's corresponding thresholds were lower in those locations. [1]
References for this detail (1)
- Tropical moisture to bring storms, flash flood risk to Las Vegas area through Tuesday - Las Vegas Sun Newslasvegassun.com · Article published: Sep 28, 2026, 3:00 PM UTC
Las Vegas highs were forecast at 83 degrees Monday and 84 degrees Tuesday, below normal. Winds were expected to blow from the south or southwest Monday before shifting north Tuesday. [1]
References for this detail (1)
- Tropical moisture to bring storms, flash flood risk to Las Vegas area through Tuesday - Las Vegas Sun Newslasvegassun.com · Article published: Sep 28, 2026, 3:00 PM UTC
A separate Borderland forecast said widespread rain could produce 1 to 2 inches across much of the region, with stronger or repeated thunderstorms generating localized totals of 3 to 4 inches or more. It also said soils were already saturated after recent heavy rain. [2]
References for this detail (1)
- ABC-7 First Alert: Tropical Moisture Set to Bring Heavy Rain, Flooding Threat to the Borderlandkvia.com · Article published: Sep 28, 2026, 8:08 PM UTC
Context from the sources
The Las Vegas forecast linked the Southwest moisture to Hurricane Polo and Hurricane Odalys, saying the systems could combine to add to heavy rainfall and flash-flood threats. [1]
The El Paso Borderland forecast identified an upper-level low over northern California and moisture from Hurricane Polo as contributors to the regional rain pattern, with the threat extending through Wednesday morning. [2]
Explore the sources and reporting timeline
2 source links · 2 domains
These counts describe the references, not independent confirmations. Different outlets can repeat the same original report.
Source timeline
Oldest to newest among the available source dates, not a chronology of the incident. Article publication dates come from the source; other recorded dates may reflect when a link was found.
- [1] Tropical moisture to bring storms, flash flood risk to Las Vegas area through Tuesday - Las Vegas Sun Newslasvegassun.comReferenced for: detail 1, detail 2, detail 3, detail 4, detail 5
- [2] ABC-7 First Alert: Tropical Moisture Set to Bring Heavy Rain, Flooding Threat to the Borderlandkvia.comReferenced for: detail 6
Questions answered by the reporting
Which areas face the greatest flash-flood risk?
Mohave County and the Colorado River Valley face a moderate risk, while eastern Clark and Lincoln counties, southern Nevada, and eastern San Bernardino County also face elevated concerns. [1]
What hazards accompany the heavy rain?
The forecast includes sudden gusts exceeding 40 mph, dangerous lightning and rapidly deteriorating boating conditions on Lake Mead, Lake Mohave and Lake Havasu. [1]
What this could mean for you
Road journeys may face sudden flooding, heavy rain, lightning and strong wind.
Localized thunderstorms can produce rapid runoff, while the forecast identifies flash flooding as the main concern for drivers.
Reported basis: [1][2] · The possible effect is interpretation.
Depends on: The risk is greatest where storms repeatedly pass over the same area or rain falls on already saturated ground.
Possible time frame: days, if those conditions hold.
Boating conditions may deteriorate quickly on three major lakes in the region.
Thunderstorms can bring dangerous lightning and gusts exceeding 40 mph, making conditions hazardous on exposed water.
Reported basis: [1] · The possible effect is interpretation.
Depends on: The risk rises when thunderstorms move across or near Lake Mead, Lake Mohave or Lake Havasu.
Possible time frame: days, if those conditions hold.
Possible consequences, not a forecast. Their relevance depends on your location and the conditions above.
For your country
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What changes the outlook
Risk increases if…
Repeated thunderstorms produce localized totals above the forecast ranges.
Heavy rain falls over the already saturated soils identified in the Borderland forecast.
Pressure eases if…
The moisture system moves east as forecast on Tuesday without repeated storm bands.
Thunderstorms remain scattered rather than training over the same communities.
Still unclear
The sources do not establish whether flooding, injuries or major damage occurred in any specific community.
The timing and location of the heaviest individual thunderstorms remain uncertain within the broader forecast area.
Market implications
Market impact
Sources (2)
References for the reported details. Separate links do not necessarily mean independent confirmation.
Available excerpt
Tropical moisture will bring widespread showers and thunderstorms to Southern Nevada through Tuesday, the National Weather Service in Las Vegas said Monday, with the greatest…A short excerpt from our source record; open the original for the full article.
Available excerpt
EL PASO, Texas (ABC-7) — A major surge of tropical moisture is headed toward the Borderland this week, setting the stage for several days of…A short excerpt from our source record; open the original for the full article.
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