4/25 severe weather potential, forecast question

[Todd Friskey]

Still new at my own attempts in trying to forecast, I have a question in regards to today's severe weather potential out in Western Oklahoma. I have been reading today's post from those who are headed to the region where the likelihood of severe weather will occur today. From what I gather there is going to be a lot of people out in that area setting up shop, so to speak. I am reading the NWS public forecast for Western Oklahoma and the Texas region. The NWSO's at Amarillo and OKC only give a range anywhere from 20 to 40% chance (ATTM) of thunderstorms even developing within SPC's risk graphic. For some reason I figured these percentages would be higher, with the model data and conditions becoming ripe later today. The moisture is definitely evident. I mean if it was me and I saw the percentages in my area, lets say 80% and that conditions were favorable, I'd be out in a heartbeat. Does a slight or moderate chance of T-storms ever play into the decison making process to go out or is it more what the models depict. But knowing how mother nature likes to throw curves on occasion, I hope its not a bust for anyone. Its hard for me to explain what I am getting at. Please enlighten me with any information you might have to if you have time to post. I will be watching from work today.

 

[Jason Boggs]

Right now 1pm, the front has hit Amarillo. It has also hit the NE TX panhandle. I think the play today will be east towards Shamrock, TX and to the SE along the dryline. There is a chance for strong tornadoes near and after dark once the LLJ cranks up. Helicity values will go through the roof, and if supercells can stay discrete, large tornadoes will be a possibility.

 

[GPhillips]

I am reading the NWS public forecast for Western Oklahoma and the Texas region. The NWSO's at Amarillo and OKC only give a range anywhere from 20 to 40% chance (ATTM) of thunderstorms even developing within SPC's risk graphic.

20 to 40% chance does not necessarily mean a 20 to 40% chance of any thunderstorms even developing, it means that at any one location, there is that chance. So, for one example, if scattered thunderstorms are virtually certain to develop, but the forecaster thinks that with the scattered coverage of those thunderstorms, there is only a 20 to 40% chance for any given location to get rain, then you'll see those probabilities in the forecast. It's a little more complicated than that, but that is the general idea.