Mesoscale Discussion 0036
NWS Storm Prediction Center Norman OK
0935 PM CST Sun Jan 21 2018
Areas affected...Northeast Texas across Arkansas and into far
Concerning...Tornado Watch 1...
Valid 220335Z - 220530Z
The severe weather threat for Tornado Watch 1 continues.
SUMMARY...The threat of a couple tornadoes as well as damaging winds
will likely spread east of the existing watch, and a new watch may
be needed by 5Z.
DISCUSSION...A southwest-northeast oriented zone of thunderstorms
has become more productive over the past few hours, as wind fields
continue to increase. Only modest levels of instability exists, but
low-level flow is strong. A few storms have shown signs of
possible/brief tornadoes with little or no lightning, suggesting
minimal instability is needed.
Sporadic severe storms currently exist from northeast TX across
western AR. Additional storms may develop southward into
east-central TX and northwest LA, with shear favoring supercells and
perhaps a tornado or two.
As the cold front reaches the existing batch of storms, they will
likely merge into a line and accelerate eastward. Models suggest
that some threat will likely persist across central AR, and perhaps
far southern MO as warm advection creates minimal instability there.
Overall, the threat is expected to weaken as it approaches the MS
river late tonight.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 31889345 31709423 31829504 32159540 32499564 32979568
34529495 36019416 37089296 37269174 36979108 36119105
34339184 32999249 32509268 31889345