Monsoonal moisture over the Southwest will lessen somewhat early this week, but downpours will persist for some, leading to more flash flooding.
Moisture has been streaming northward into the southwestern quadrant of the U.S. over the last few days, leading to widespread drenching thunderstorms each afternoon and evening.
The moisture was streaming around a strong area of high pressure which was centered over the eastern Rockies and High Plains.
This high pressure system will continue to weaken and shift eastward as a large dip in the jet stream develops over the West Coast.
As the jet stream dives southward it will send that monsoonal moisture eastward, effectively drying out parts of the Southwest.
Still, enough moisture will persist through much of the upcoming week to produce more downpours and instances of flash flooding for some.
Heavy rains occurred on Saturday over southern Yavapai County, Ariz. where forest fires had left large burn scars. 2-4 inches of rain over this region in a short time lead to debris flows and mudslides as well as flooding of Turkey Creek and the Agua Fria.
A local bridge was washed out on the Havasu Creek at Supai, Ariz. as well.
More instances of flash flooding will occur through the first half of this week a bit farther east over the Colorado Rockies, eastern Arizona, and much of New Mexico while areas farther west dry out.
Daily bouts of drenching afternoon and evening thunderstorms will be common from Denver and Boulder, Colo. through Albuquerque, N.M. and Nogales, Ariz.
Thunderstorms across this region can produce rainfall rates of 1-2 inches per hour which is more than high enough to get flash flooding to occur. Especially since moisture values have been elevated for quite a while now.
Along with the heavy rainfall, dangerous cloud to ground lightning will threaten to postpone or delay any outdoor activities.
If flash flooding is occurring or imminent, take the proper precautions if you need to to travel. Never drive through a flooded roadway because you never know how deep the water might be.
Always carry an emergency kit in your vehicle in case you become stranded.
Heed all flash flood watches and warnings and keep an eye on the AccuWeather.com Severe Weather Center.
As temperatures rise through the weekend in the South, so will the risk for heat-related dangers.
While a tropical low is expected to brew into Tropical Storm Cristobal this weekend, the East Coast of the U.S. is being monitored for future impacts -- even if the storm remains well offshore.
United States residents may pay higher heating costs this fall as colder air is expected to grip the Rockies and Plains at times and some quick-hitting chilly shots may impact the Northeast.
A swath of soaking rain will slowly shift from the northern Plains to the Canadian Prairies this weekend, making people reach for their umbrellas and heightening concerns for flooding.
While residents will face more disruptions to outdoor activities on Saturday, dry air will push southward across Pittsburgh to end the weekend.
The Great Gust of 1724 in Virginia. The storm forced a temporary prohibition in the export of Indian corn.
Denver, CO (1921)
2.20 inches of rain in 1 hour.
Chesapeake Bay Area (1933)
Hurricane - 6.39 inches of rain in Washington, D.C. Damage in Maryland close to $17 million. Tide 7 feet above normal flooded Norfolk, VA.