What is a TUTT system?

[ntxweatherwatcher]

I am curious exactly what at TUTT system is, and what that would mean for Texas if this NWS posting came to fruition? (see bottom of forecast discussion)

Area forecast discussion
National Weather Service Fort Worth Texas
258 PM CDT Thursday Jul 30 2009


Discussion...
the front has reached a Comanche to Sherman line and will move
into the southern County Warning Area overnight and stall. Isentropic lift up and
over the frontal boundary will be best over the southwestern and
southern counties later tonight and thats were we have the better
probability of precipitation. Will keep chance probability of precipitation going over the southern half Friday
then shift chance probability of precipitation to the northern half Friday night through
Sunday as the stalled front lifts north Friday night then returns
Saturday night. Do not expect significant severe storm activity
across the County Warning Area tonight...but a few of the strong storms with
heavy rainfall could produce localized flooding over the southwest
County Warning Area.


Lows tonight will be quite pleasant north of the front with rural
areas dropping into the upper 60s. Highs Friday will be normal or
slight above over the far southern counties...but only in the
upper 80s to lower 90s to the north. Similar highs/lows are
expected Saturday and Sunday.


For next week...the upper trough encompassing almost the entire
Continental U.S....will shift its axis toward the eastern coast with the
western upper high rebuilding over the southern and Central
Plains. This will bring hot (96-102) and dry weather back to the
region...especially over the Central Plains. One thing of interest
is that the GFS is indicating that as the upper highs becomes
centered over Oklahoma...a TUTT will develop over the northern
Gulf and track westward across south Texas middle week. Depending on
its location Wed-Fri...it could bring a tropical airmass into the
region and maybe some convection. We will wait several more models
runs before committing to this. 75

[x-y-no]

TUTT stands for Tropical Upper Tropospheric Trough. Either a trough or a cut-off upper low. In the tropics/subtropics these can be fairly long-term self-sustaining features, maintained by a balance of subsidence warming and radiational cooling.