U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus02 kwns 190420 
Storm Prediction Center ac 190420 

Day 2 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1120 PM CDT Wed Oct 18 2017 

Valid 201200z - 211200z 

..no severe thunderstorm areas forecast... 

some thunderstorm potential will exist across the south-central US 
and over the upper Mississippi Valley and across parts of southern 


Higher-precipitable water air mass will begin to advance north across the western 
Gulf basin into the plains during the day2 period as broad troughing 
establishes itself across the western parts of the US. One 
low-latitude short-wave trough will eject across the southern High 
Plains into OK/North Texas during the afternoon and this should enhance 
low-level warm advection such that isolated-scattered convection may 
develop as air mass moistens. Forecast soundings do not exhibit 
significant instability but adequate buoyancy should exist for 
deeper updrafts to penetrate levels necessary for lightning. Weak 
lapse rates and the lack of a strong focus suggest the probability 
of severe is too low to warrant a severe risk this period. 

Farther north, low-level warm advection will increase markedly 
during the latter half of the period as strong low level jet develops from Kansas 
into Minnesota. Forecast instability is quite weak along this corridor but 
likely adequate for a few elevated thunderstorms. 

Upper ridge will dominate the southeastern US during the day2 period 
and a dominant surface high should hold over the southern 
Appalachians. As a result, deep easterly flow will persist across 
the Florida Peninsula. Deeper showers will congregate across the eastern 
and southern peninsula and isolated lightning could develop with 
this activity. 

.Darrow.. 10/19/2017