U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus03 kwns 170711 
Storm Prediction Center ac 170710 

Day 3 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0210 am CDT Tue Jul 17 2018 

Valid 191200z - 201200z 

..there is a marginal risk of severe thunderstorms across parts of 
the middle Missouri and upper Mississippi valleys... 

A marginal severe threat will be possible on Thursday across parts 
of the mid Missouri Valley into the upper Mississippi Valley. 

..mid Missouri Valley/upper Mississippi Valley... 
A shortwave trough is forecast to move eastward into the upper 
Mississippi Valley on Thursday as a cold front advances 
southeastward across the northern plains. The models are forecasting 
a moist airmass to be in place across the mid Missouri and upper 
Mississippi Valley where surface dewpoints should be upper 60s to 
lower 70s f. As a result, moderate instability appears likely to 
develop across much of the moist sector by Thursday afternoon. Model 
forecasts are not in agreement on where convective development will 
be most probable. The NAM is forecasting late afternoon storms in 
western Minnesota while the GFS and European model (ecmwf) show storms in southern 
Minnesota and east-central Iowa. This outlook favors the GFS and 
European model (ecmwf) solutions which suggest an isolated severe threat will be 
possible in western portions of the upper Mississippi Valley. A 
marginal risk area has been added from near the Mississippi River in 
northeast Iowa westward into southeastern South Dakota and northeast 
Nebraska where storm coverage may be isolated but strong instability 
is forecast. Marginally severe wind gusts and hail will be possible 
with the cells that develop in areas with the strongest instability. 

.Broyles.. 07/17/2018