Locally severe storms and flash flooding are threatening bone-dry portions of western and southern Texas this week.
A nearly stationary front draped across southern and western Texas and extending back into New Mexico will be the focal point for rounds of thunderstorms through the end of this week.
The thunderstorms will be most widespread each afternoon with the aid of daytime heating.
Runoff is generated very quickly in these typically arid locations, so downpours threaten flash flooding. Repeated downpours hitting the same communities will heighten this threat.
"Dry stream beds, known to locals as arroyos and washes can rapidly fill with water. Keep children from playing in these areas. Use caution at low water crossings and be alert for rapidly changing weather conditions upstream," AccuWeather.com Expert Senior Meteorologist Alex Sosnowski said.
By Thursday and Friday, a storm system tracking in from the West will force the rain and the storms to shift expand eastward across central and eastern portions of Texas and the southern Plains. Over the weekend, the lower Mississippi Valley will be the target of locally drenching showers and thunderstorms.
Severe thunderstorms could rattle across South Texas on Thursday afternoon as the storm system approaches from the west. Corpus Christi and Laredo are among the communities that should pay close attention to rapidly changing weather conditions and threatening storms late Thursday.
Large hail and damaging wind gusts will be the primary concerns with these storms. However; an isolated tornado cannot be ruled out.
East Texas, including the Houston area, may deal with a few severe thunderstorms on Friday.
A new round of showers and thunderstorms may unfold across the southern Rockies and West Texas next week.
The Rain is Welcome in Texas
According to the U.S. Drought Monitor, western and southern portions of Texas are still suffering from severe to exceptional drought conditions.
From Aug. 2010-Present
"In many cases, the roots of the current drought extend into the late summer of 2010 with rainfall of only 25 to 50 percent of normal," Sosnowski said.
"While rainfall in these arid areas is typically lean, cutting the rainfall by one half to three-quarters over the long term can have serious consequences on agriculture, drinking water and recreation. A lack of snow in northern New Mexico this winter, combined with the ongoing overall drought is seriously impacting water levels on the life-giving Rio Grande River."
The rain this week is not expected to be drought-busting, but any rainfall is welcome across the region. More rain on a "regular basis" would be needed to entirely reverse the drought conditions in places across West Texas, according to Sosnowski.
The AccuWeather.com 2012 Summer Forecast calls for some beneficial rain early in the season in southwestern portions of Texas as tropical moisture from the Gulf of Mexico will be drawn around the back edge of a dome of high pressure dominating the Plains. However, the Texas Panhandle is expected to remain hot and dry.
Temperatures will be a few degrees below average across the UK this weekend, but largely dry conditions are expected.
After no rain for almost a month, Santiago braces for rain early in the week. Cool air follows, spreading into Chile, Argentina and Uruguay mid-week.
There is a significant chance that Jimena will turn back toward Hawaii and threaten the islands during the second week of September.
An unusually strong push of cool air for early September will move southward along the Atlantic Seaboard into the Labor Day weekend before July-like heat returns by next week.
Steering winds could take Ignacio, as a remnant storm, into the southeastern arm of Alaska or British Columbia during the middle days of next week.
Strong thunderstorms will roll across the Upper Midwest while rain and strong winds roar through the Northwest this weekend.
Washington, DC (1939)
"Once in a hundred-year rainstorm" 4.40 inches in 2 hours at the Washington Zoo.
Minneapolis, MN (1941)
Tornado - 5 dead - $450,000 damage.
Greatest natural disaster for Arizona. Rains in central Arizona caused rivers to rise 5-10 feet per hour, sweeping cars and buildings 30-40 feet downstream. Twenty-three lives were claimed by the floodwaters. This rain came from Tropical Storm Norma.