Split Flow Pattern

The pattern we are sliding into over the weekend and coming week will favor active weather.  This is because we are transitioning to a split flow pattern.

So what is a split flow pattern?  Below is a depiction of the Jet Stream placement around 6 AM Friday.  The jet stream is a band of strong air currents that encircles the hemispheres (one in each) several miles above earth’s surface.  This is the conveyor belt that storm systems ride along to give us everyday weather conditions.

GFS Model Depiction of the Jet Stream valid 6 AM Mon
GFS Model Depiction of the Jet Stream valid 6 AM Fri 2/1/14

Notice the uniform direction of the jet stream in the above picture.  Split flow is beginning to evolve, with a northern branch starting to organize.  It features your standard west to east movement in a uniform manner.  However, that may change in the weekend and early next week.

GFS Model Depiction of the Jet Stream valid 6 AM Mon
GFS Model Depiction of the Jet Stream valid 6 AM Mon 2/4/14

Notice now there are two branches of the jet stream.  One branch extends from the northern Pacific, down to Baja California, northeastward into the Texas panhandle, then east of there.  The other branch is further to the north, extending out of Canada and moving into the northern United States.  This is what is meant by a split flow pattern.

This split flow pattern often leads to a time of active weather. When reading the forecast posts, notice the increase in precipitation chances. This will likely continue into next week.