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.
Sun and warm temperatures will be disrupted by weekend rain and possible thunderstorms.
Cold air sweeping in this weekend will help pave the way for a snowstorm Sunday afternoon into Monday morning around Harrisburg, Pennsylvania.
Cold air sweeping in this weekend will help pave the way for a winter storm Sunday into Monday morning around Pittsburgh.
A snowstorm reaching Detroit on Sunday will bring colder air and 3 to 6 inches of snow, and more snow is expected next week.
Cold air sweeping in this weekend will help pave the way for a snowstorm by Monday around Boston.
Cold air sweeping in this weekend will help pave the way for a snowstorm Sunday night into Monday around New York City.
Northway, AK (1989)
Record high barometer reading of 1978.4 mb (31.85 inches) -- North American record.
Minneapolis, MN (1990)
Never below zero this January for the first time on record for January.
Atlantic City, NJ (1990)
All-time warmest January followed the coldest December on record (December 1989).