Southwest US: Bud's moisture to fuel flooding downpours late Friday into the weekend
Hurricane Bud continues to slowly churn towards the southern tip of Baja California Tuesday afternoon. Bud, a once Category 4 powerhouse, is now weakening as it travels over cooler ocean water and will likely be a tropical storm once it makes landfall across southern Baja California late Thursday.
Aletta, no longer a tropical system, and Hurricane Bud are shown in this satellite image. Terra/MODIS from NASA.
The circulation of Bud will dissipate by Friday as it moves into Sonora. However, an abundance of tropical moisture will be leftover and will be pulled northward into the Southwest U.S. by an upper-level trough over the West.
The combination of this upper-level trough, energy leftover from Bud, and the tropical plume of moisture will lead to heavy showers and thunderstorms across the Four Corner states late Friday into Saturday night.
An upper-level trough in the West will pull what is left of Bud and it's moisture into the Southwest U.S. Friday into Saturday night.
Precipitable water, an indicator of moisture in the atmosphere, will increase as tropical moisture is pulled northward. The abundance of tropical moisture will fuel downpours and lead to flash flooding.
These storms will be able to bring heavy rainfall in a short amount of time so flash flooding will be possible. Dry stream beds will temporarily turn into raging rivers in some areas so people are urged to use extra caution and be aware of their surrounding conditions.
On average, most showers and storms will bring 0.25 to 0.75 inches of rain but there will be isolated areas that receive 1 to 2 inches in a very short time.
Many will view this rain as a positive thing as the region continues to deal with drought and wildfires.
However, there will be other threats with these storms. Gusty outflow winds can kick up and blow around dust, leading to poor visibility and dangerous air quality. Lightning can also create new wildfires if it occurs in areas outside of the heaviest rain.
Drier air will begin to work back in across the Southwest Sunday and things will begin to turn back to normal.