AUSTIN (KXAN) - The environment over northern portions of south-central Texas will become very conducive for a severe weather outbreak this afternoon and evening, and I will be in the field Tuesday afternoon tracking the thunderstorms along with experienced local storm chaser Randy Denzer.
Meteorologists look at many variables to determine the potential for severe thunderstorms and tornadoes. Today, all of those variables are perfectly aligned in the most favorable severe weather and tornado setup the area has seen in at least a year.
Convective Available Potential Energy, or CAPE, and Lifted Index, called LI, are measures of how powerful thunderstorm updrafts will be, based mainly on the basic principle that warm air rises. By Tuesday afternoon, CAPE values are forecast to push above 5,000 J/Kg. That is a technical measurement that shows the massive amount of energy these thunderstorms will have
This is the highest number I have ever seen regardless of geographical area. LI values later today will approach -15, again the highest I have ever seen.
These almost unheard-of CAPE and LI values will lead to very powerful thunderstorm updrafts. The more powerful the updrafts, the taller the storms will become (up to 55,000 feet!) and the larger hail the storms will create.
In addition to tall, powerful thunderstorms with large hail, we are also expecting many of these supercells to rotate.
Meteorologists measure the rotation of a thunderstorm updraft (which creates a tornado) by a value called helicity. Think of helicity as the amount of corkscrew-twist that rising air inside of the storm will have. Helicity values this afternoon from the surface to inside of the thunderstorm are expected to be between 400-500, meaning the storms will be rotating enough to support tornado development - possibly even violent tornadoes.
As the atmosphere primes itself for a severe thunderstorm outbreak in central Texas this afternoon and evening, stay tuned to KXAN for the latest.
Late Saturday night into early Sunday morning, a light band of freezing drizzle traversed the I-35 corridor eastward. With sub-freezing temperatures, even the light precipitation created major problems.
A 10-year-old was killed while standing outside a vehicle after the child's family was involved in a fender bender, DPS said.
Austin Police are looking for a missing woman.
APD is responding to a 25 vehicle accident near the 5400 block of Ed Bluestein near Thurgood Ave.
A man is dead after being hit by several vehicles in the eastbound lane of Highway 71 Saturday night.
A representative at the Fayette County Sheriff's office said that Fayette County is effectively shut down due to icy conditions.