U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus02 kwns 191702 
Storm Prediction Center ac 191701 

Day 2 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1201 PM CDT Tue Sep 19 2017 

Valid 201200z - 211200z 

..there is a marginal risk of severe thunderstorms from the u.P. Of 
Michigan to northeast Kansas... 

A few severe storms are possible from northeastern Kansas 
northeastward to the Upper Peninsula of Michigan Wednesday afternoon 
and evening. 


Strong short-wave trough is expected to eject across the upper Red 
River valley as a 500mb speed Max translates across eastern ND 
toward the international border region of northern Minnesota. Height falls 
will focus across this region early in the period before shifting 
into northwest on where large-scale forcing for ascent should 
encourage convection along/ahead of cold front. 

In the wake of the short-wave, surface pressures will rise across 
the plains which will drive a surface front to a position from 
western WI, southwest into central Kansas by early afternoon. Strong 
capping along this boundary should inhibit thunderstorm development 
until later in the day when boundary-layer heating should weaken cin 
such that parcels, assisted by frontal ascent, are capable of 
reaching their level of free convection. While large-scale ascent will focus across 
Canada, it appears strong, potentially severe, thunderstorms will 
develop along the wind shift within a sheared environment supportive 
of sustaining organized updrafts. Large hail and damaging winds are 
the primary threats with line segments/clusters that should mature 
during the late afternoon/early evening. This activity should linger 
into the overnight hours across this mid-Mississippi Valley as the 
front stalls and convection is aided by a veered low level jet into northern 

A few strong storms could evolve along the dry line across the 
Southern Plains but overall the severe threat appears too limited to 
warrant 5% severe probs at this time. 

.Darrow.. 09/19/2017