U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus03 kwns 220742 
Storm Prediction Center ac 220742 

Day 3 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0242 am CDT Wed may 22 2019 

Valid 241200z - 251200z 

..there is a slight risk of severe thunderstorms from a portion of 
the Central Plains into the upper Mississippi Valley region... 

A few strong to severe storms will be possible on Friday from a 
portion of the upper Mississippi Valley region into a part of the 
central and Southern Plains. 


Model consensus is that a shortwave trough initially over the 
central/northern plains early Friday will continue northeast into 
the upper MS valley region during the day. Attendant surface low 
initially over South Dakota will reach Minnesota by mid-late afternoon with trailing 
cold front extending southwest through Iowa and central Kansas. A warm 
front will advance northeast through the upper MS valley and by 
early evening should extend from the surface low in Minnesota through the 
southern Great Lakes and into the Ohio Valley. Dryline will reside 
across West Texas during the day, but should retreat into eastern nm 
during the evening. 

..eastern Kansas through the upper Mississippi Valley region... 

Richer low-level moisture with mid-upper 60s f dewpoints will advect 
northeast through the mid-upper MS valley warm sector during the day 
and this should contribute to a corridor of moderate instability 
(1500-2000 j/kg mlcape) as the boundary layer warms. Some storms may 
be ongoing on cool side of the warm front as well as farther west 
across Kansas in vicinity of the cold front. Additional storms will 
probably develop along the cold front or residual outflow boundaries 
during the afternoon. Flow in the lowest 3 km is forecast to weaken 
and the strongest mid-upper winds will likely remain north of the 
warm sector which could be limiting factors for a more robust severe 
threat. However, winds aloft will support 40-45 kt largely 
unidirectional effective bulk shear. It appears the parameter space 
will be sufficient for a threat of some strong to severe storms with 
large hail and damaging wind the main threats through early evening. 

..southern High Plains area... 

Storms may be ongoing from a portion of West Texas into OK which 
complicates the forecast to some degree. Nevertheless, initial 
activity may weaken, with potential for boundary-layer recovery 
during the afternoon, potentially supporting strong instability with 
2000-3000 j/kg MLCAPE. A belt of 40-50 kt mid-level winds will 
persist over this region, therefore the parameter space will be 
conditionally supportive of severe storms. While dryline convergence 
is not expected to be particularly strong and forcing aloft will be 
weak, potential still exists for isolated storm development either 
along the dryline or in association with residual boundaries from 
early convection. Will introduce a marginal risk category this 
update, but an upgrade to higher probabilities may be needed in 
future outlooks once some of the mesoscale uncertainties have been 

.Dial.. 05/22/2019