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.
Join us weekdays at noon and Thursdays at 4 p.m. EST and for enhanced breaking coverage when severe weather strikes.
Following a southward push of cool, dry air at midweek, clouds, showers and higher humidity will return to the Northeast.
Even though the tremendous rains have come and gone, flooding will continue on the major rivers in the South Central states for the next couple of weeks.
Another round of storms will fire across the northern Plains at midweek with the chance for isolated tornadoes.
Major hurricane Blanca will threaten Baja California with flooding rain and damaging winds this weekend.
While the center of Andres will remain a thousand miles away, its moisture will still get drawn into the Western United States and enhance thunderstorm activity later this week.
Dulles Airport, Washington, D.C. (1991)
4.25 inches of rain -- normal for all of June is 4.23 inches.
Great Comanche Tornado commenced near Cedar Rapids, IA, and ended over Lake Michigan; 175 killed, destroyed Comanche village on Mississippi River.
Thunderstorms in northwestern Kansas produced up to 18 inches of hail near Salden during the early evening. Crops were completely destroyed and total damage from the storm was nearly 500,000 dollars. Temperature dropped from near 80 degrees before the storm to 38 degrees at the height of the storm.