Mesoscale Discussion 0034
NWS Storm Prediction Center Norman OK
0625 PM CST Sun Jan 21 2018
Areas affected...Northeast Texas...southeast Oklahoma...western
Concerning...Tornado Watch 1...
Valid 220025Z - 220230Z
The severe weather threat for Tornado Watch 1 continues.
SUMMARY...The threat of a tornado or two persists from northeast
Texas into western Arkansas, and may increase over the next few
hours. A few damaging wind gusts are also possible this evening.
DISCUSSION...An initial zone of storms persist within a zone of
deeper low-level moisture convergence, near the wrn edge of the
low-level jet. Weak but sufficient instability remains in place for
strong to severe storms, given the presence of low 60s dewpoints and
continued cooling aloft. The 00Z FWD sounding shows a rather deep
boundary layer, but also resides farther west near a cold front
aloft with veered winds at 850 mb. In addition to cooling aloft,
rapid drying is also occurring.
Shear profiles farther east near the low-level jet axis remain
favorable for supercells, and several small storms have shown at
least weak mesocyclones. The strongest cell is currently over
Navarro county TX with a well defined mesocyclone. The southern end
of this line also has access to slightly better moisture, and a
tornado or two cannot be ruled out.
With time, convergence will increase along the approaching front,
and this may boost overall storm activity, perhaps consolidating it
into more of a line. Shear will remain favorable as this line
advances eastward, with a wind and QLCS tornado threat.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 35669426 35649368 35529317 35319288 35019279 34429290
32869353 32209382 31789448 31609501 31629538 31599625
31719666 31929667 32859629 33949571 34819535 35439499