October 8th and 9th was the first measurable rain we have seen across the area since back on September 17th. Here are some of the totals from the past 48 hours.
There appears to be more where that came from, and maybe much more. With a potentially soaking rain (which we have desperately been waiting for and need) may also come the threat for severe weather during the day on Saturday. Right now the system that will eventually affect the Upper Midwest is spinning off of the coast of California. The red “L” just below Sacramento marks the current position of the storm. The other two “L’s” mark the track of where the Upper Level Low is currently forecast to go. We are looking at it on the water vapor imagery. This type of satellite imagery shows the amount of moisture in the mid to upper levels of the atmosphere. It is easy to see how the atmosphere is moving if there was a loop of the image below.
The Upper Level Low seen above on the water vapor imagery will act as the fuel for a surface low that will eventually develop east of the Rocky Mountains. Once the low emerges from the Rockies, it is forecast to deepen (strengthen) and push up into the Upper Midwest. A warm front will deliver slightly warmer air to area on Saturday. The warm sector will be the focal point for any potential severe weather to develop. The warm sector is the area below the warm front (Red Half Circles) and to the east(right) of the cold front. (Blue Triangles) As far as timing goes, it looks like we will watch clouds increase Friday night and may even start to get in on some showers that night as well. That is associated with some energy out ahead of the warm front that looks to cross the area on Saturday morning. Below is how things may look on Saturday from a surface weather map perspective.
The Storm Prediction Center has outlined the area in a Severe Risk for thunderstorms during the day on Saturday. What that basically means is that at this time with all of the weather data we have, if things hold together as they look now we will run the potential for severe thunderstorms to develop.
As many of you know, things can change in an instant with the weather. The main body of this system is after all still offshore of the west coast of the United States and a lot can certainly change. It does appear though at this point a soaking rain is likely with some places possibly picking up near an inch of rain or more, and severe thunderstorms may accompany this rain on Saturday. We are keeping an eye on this storm. Keep checking back for updates and changes as this storm system gets closer to the Upper Midwest.
This post was written by jkegges on October 10, 2012