U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 240056 
Storm Prediction Center ac 240055 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0755 PM CDT Fri Mar 23 2018 

Valid 240100z - 241200z 

..there is a slight risk of severe thunderstorms along portions of 
the Nebraska/Kansas border... 

..there is a marginal risk of severe thunderstorms surrounding the 
slight risk...and extending westward into northeast Colorado... 

Isolated large hail and possibly a strong wind gust or two remain 
possible this evening near the Kansas-Nebraska border. 

Latest radar loop shows that storms have developed/evolved into a 
short line segment near the Kansas/Nebraska border, with the 
strongest updraft over Norton County Kansas. This small cluster of 
near surface-based convection has developed in the immediate 
vicinity of the surface low and warm front, and should track 
east-southeast over the next couple of hours. 

South of the warm front, the warm sector remains capped -- per the 
latest model forecasts and inference from the evening raobs. With 
the onset of diurnal cooling now indicated, expect this cluster of 
cells to be short-lived, with risk for gusty winds and/or hail for 
the next 1-2 hours. 

Farther east, continued warm advection may allow elevated convection 
to expand somewhat over the next several hours, across southern 
Nebraska and northern Kansas and vicinity. Marginally severe hail 
may be possible with one or two of the strongest cells. 

Some low-end risk for gusty winds may persist for another hour or so 
across northeast Colorado, with weak convection ongoing across this 

.Goss.. 03/24/2018 


Mesoscale Discussion

acus11 kwns 240103 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 240102 

Mesoscale discussion 0169 
National Weather Service Storm Prediction Center Norman OK 
0802 PM CDT Fri Mar 23 2018 

Areas affected...portions of eastern South Dakota...southwestern Minnesota...and 
northern Iowa 

Concerning...heavy snow 

Valid 240102z - 240700z 

Summary...a band of heavy snow will develop through the evening, 
with snowfall rates around 1 inch per hour likely. 

Discussion...a band of rain/thunderstorms across southeastern South Dakota 
into northwestern Iowa as of 01z is being supported by lift associated 
with a shortwave trough ejecting northeastward over the 
northern/Central Plains. A strengthening southeasterly low-level jet 
will increase in the thermal gradient around 850 mb. Although some 
sleet may occur initially, forecast soundings from the NAM/hrrr 
suggest mid-level cooling with the approach of the shortwave trough 
will encourage a fast transition from rain to snow across eastern South Dakota 
into southern Minnesota and northern Iowa as ongoing precipitation shifts 
into this area through 03-05z. 

A band of heavy snow will develop across this region later this 
evening into the early overnight hours, with strong low-level 
frontogenetic forcing and deep ascent occurring through the 
dendritic growth zone likely supporting snowfall rates around 1 inch 
per hour. Some localized higher rates to around 2 inches per hour 
may be possible within convective elements of the band, and an 
isolated lightning strike or two cannot be ruled out. Of note, there 
will likely be a sharp northern gradient to the heavy snow due to a 
residual dry low-level airmass being reinforced by strong 
east-northeasterly surface winds across parts of central/eastern Minnesota. 

.Gleason.. 03/24/2018 

..please see www.Spc.NOAA.Gov for graphic product... 


Latitude...Lon 44179713 44569745 45219736 45639677 45579617 45379555 
45039488 44619427 44229364 43929318 43529272 43089247 
42759242 42569291 42969378 43329480 43449561 43709648