Day 1 Severe Weather Outlook

Valid 102000Z – 111200Z


Widespread severe thunderstorms are likely across the southern Great
Plains, mainly this afternoon and evening, spreading east into the
Lower Mississippi Valley tonight. The most dangerous corridor for
strong tornadoes and intense damaging winds should be centered on
northeast Texas through northern Louisiana and southern Arkansas
this evening through the overnight.

Only relatively minor changes were made to the previous convective
outlook. Those changes are listed according…1) removal and/or
eastward adjustment of severe probabilities over parts of western
OK/south-central KS. 2) including the greater St. Louis metro in a
categorical slight risk for the possibility of wind damage from
squall line activity later this evening. 3) Lowering severe hail
probabilities over east-central OK from 30-percent to 15-percent
based on ongoing convective trends and the expected gradual shift of
the area of most pristine mid-level lapse rates to be farther south
into TX.

..Smith.. 01/10/2020

.PREV DISCUSSION… /ISSUED 1013 AM CST Fri Jan 10 2020/

The ongoing forecast appears to be in good shape, with no changes
made for this update.

Scattered thunderstorms have been occurring this morning over
northwest OK. These storms will persist through the day and spread
northeastward into parts of southern KS and eventually western MO.
Much of this activity appears to be elevated, with the primary risk
being hail.

12z model solutions are in solid agreement that intense convection
will form by mid afternoon roughly along the low-level jet axis
across central/eastern OK – building southward into north-central
TX. Forecast soundings show very strong vertical shear and
sufficient CAPE for a few supercells, along with bowing structures.
Damaging winds and tornadoes will be possible with the strongest
cells. A strong tornado is possible. Severe storms should spread
eastward into western AR after dark.

By late afternoon, a line of intense storms should develop from
northeast into east-central TX. These storms will track eastward
into a progressively more sheared and moist environment. Large hail
will be the primary threat initially, but storms will quickly evolve
into bowing structures with increasing risks of widespread damaging
winds and a few tornadoes through the night. Forecast soundings
show minimal cap ahead of the line, along with intense low-level
shear and ample boundary layer moisture. This suggests the
potential for a few discrete storms to form ahead of the squall line
as it moves across parts of AR/LA overnight. These storms would
have the most prominent threat of strong tornadoes. 12z guidance is
consistent in timing the squall line into western MS and southwest
TN before Sat/12z, with a continued damaging wind and tornado


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