SPC AC 290058
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0758 PM CDT Sat Mar 28 2020
Valid 290100Z - 291200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM A PORTION
OF THE TENNESSEE AND OHIO VALLEYS INTO THE MIDWEST REGION...
Scattered severe storms posing a threat for tornadoes, damaging wind
and large hail will continue this evening into the overnight from a
portion of the Tennessee and Ohio Valleys into the Midwest region.
The warm sector is in the process of being pinched off across
northeast IA suggesting the tornado threat in this region should end
by 02Z. However...additional storms are developing farther south
across northwestern and west central IL and will move eastward into
central and eastern IL where the 00Z RAOB from Lincoln indicated
around 800 J/kg MLCAPE, large low-level hodographs and 80 kt
effective bulk shear. This environment will continue to support
organized storms incuding supercells capable of producing tornadoes,
a couple of which could be strong this evening.
...Tennessee and Ohio Valleys...
A secondary branch of the low-level jet is forecast to strengthen
tonight from middle TN into the OH Valley in association with a
strong upper jet moving through the base of a progressive trough
situated across the Midwest. This will contribute to modest
low-level theta-e advection with MUCAPE from 500 to 1000 J/kg as
well as large hodographs with 300-400 m2/s2 0-1 km storm-relative
helicity within an otherwise strongly sheared environment. The band
of scattered storms developing along the warm conveyor belt from
southwest IN into western TN and northwest MS will likely maintain
embedded organized structures including supercells and bowing
segments capable of tornadoes, damaging wind and large hail as they
develop eastward into the overnight.
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z