Mesoscale Discussion 0236
NWS Storm Prediction Center Norman OK
0209 AM CST Wed Mar 01 2017
Areas affected...Parts of sern MO...srn IL...wrn KY...cntrl/nern
AR...wrn TN and nwrn MS
Concerning...Severe potential...Watch likely
Valid 010809Z - 011015Z
Probability of Watch Issuance...80 percent
SUMMARY...A new tornado watch likely will be issued prior to the 10Z
expiration time of tornado watch 46.
DISCUSSION...Aided by forcing for ascent associated with upper
troughing now advancing across and east of the Plains, vigorous
convective development is ongoing within a couple of evolving lines.
These are focused along a cold front, and a pre-frontal confluence
zone (which appears to coincide with a 50-60 kt southwesterly 850 mb
jet), which are forecast to advance eastward across the Ozark
Plateau into the Mississippi Valley through 11-13Z.
Ahead of the convection, into the Mississippi Valley, the warm
sector air mass is moist and potentially unstable, in the presence
of large clockwise curved low-level hodographs. Isolated discrete
storm development may not be out of the question ahead of the lines.
If this occurs, they probably will be accompanied by a risk for
tornadoes and large hail. Otherwise, with the approach of the
evolving convective lines (which seem likely to maintain intensity
through at least daybreak), low-level hodographs, while remaining
strong, trend more linear, and may be accompanied by primarily a
risk for damaging surface gusts.
LAT...LON 34349429 35259286 35809254 36669188 37499072 38128952
38158845 37458775 36438812 34938961 34109126 33599349