Why does the SPC's enhanced thunderstorm outlook rarely match my local NWS forecast?

[KSWx]

As an example, the SPC has 10% all day tomorrow for Topeka:

 

 

Meanwhile on the NWS forecast for Topeka:

 

 

 

 

Can someone please tell me what I'm missing?  Thanks in advance!

[ohleary]

As an example, the SPC has 10% all day tomorrow for Topeka:

 

 

Meanwhile on the NWS forecast for Topeka:

 

 

 

 

Can someone please tell me what I'm missing?  Thanks in advance!

 

I have to imagine what your actual forecast was, since you only put an icon, but I'd guess it said "showers and thunderstorms likely. Chance of precipitation 70%".  Not 70% chance of thunderstorms.

[LocoAko]

Right. I believe the SPC graphic is the probability of thunder, while the percentage on the NWS is the probability of precipitation.