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Morning upper-air sounding launched from Fort Worth Texas. This sounding was released just around the time a cold front moved through, but reveals several important clues about this day’s atmospheric environment.
The morning upper-air sounding was launched from our office in Fort Worth just as the aforementioned cold front was passing overhead. As a result, while it is not entirely representative of the afternoon environment across Central Texas, there are several keys we are able to glean from this atmospheric sounding:
- ​Mid-level lapse rates (between about 10,000 feet and 20,000 feet), or the change in temperature with height, were impressively steep, decreasing at a rate of 7.5 degrees C for every kilometer. This is a sign that thunderstorm updrafts would be able to acquire substantial acceleration in the free atmosphere.
- Moisture, while not overly deep, was very high near the surface, with the sounding measuring a surface dewpoint temperature of 73 degrees F. Moisture content, as we’ll see in just a bit, was even more impressive across Central Texas.
- Wind shear, or the turning of winds and/or change of speed with height was fairly minimal on this day. However, deep layer bulk shear (the vector difference between the winds at about 20,000 feet and near the surface) was near 40 knots, which, combined with the very high instability, was more than sufficient for supercell thunderstorms. Very weak winds in the lower-levels, however, did not appear to be very conducive for tornadic thunderstorms.
