A potent upper-level disturbance centered over the Desert Southwest today will slowly head east and cause a severe weather outbreak for the Southern Plains and Deep South later this week.
The same system that caused needed rain and mountain snow for southern California over the past weekend and on Monday will be over the Desert Southwest today. Though it is fairly starved for moisture today, as it heads east it will tap into abundant moisture from the Gulf of Mexico that will help it cause the forecast severe weather outbreak.
Today will see showers and a few thunderstorms form over the Desert Southwest today as well as mountain snow. Winter Storm Watches are in effect for the Rocky Mountains of northern New Mexico and southern Colorado through Thursday, with a foot of snow possible at elevations over 8,000 feet. Winter Weather Advisories are in place for the San Juan Mountains of southwest Colorado and northwest portions of the Colorado Plateau of Arizona where several inches of snow could fall at elevations over 5,000 feet.
As the system continues to spin eastward, its main focus will become severe thunderstorms. The government's Storm Prediction Center has placed a Marginal Risk for severe weather over a large portion of interior Texas late Wednesday and Wednesday night. Strong southerly winds near the surface will transport Gulf of Mexico moisture northward. At the same time, winds aloft will be strong from the west and southwest. This turning off the wind will be a trigger for possible severe thunderstorm formation with strong wind gusts and even perhaps a few tornadoes being the main threat from these thunderstorms.
This severe weather threat will head eastward as the storm does. On Thursday, the severe weather threat will be over eastern Texas and by Thursday night over the southern Mississippi Valley. The main threats from this potential severe weather outbreak will continue to be strong wind gusts and a few tornadoes. The Storm Prediction Center has placed a Slight Risk for severe thunderstorms in this area for Thursday.
The best thing to do is to stay prepared and weather-aware, starting with knowing the difference between a watch and a warning should they be issued this week. A watch means that conditions are favorable for severe weather to develop, and you need to have a plan in place for acting. However, a warning means that severe weather has been indicated and/or imminent, and you need to act fast to remain safe. When in doubt remember, “When Thunder Roars, Go Indoors!”