KATC StormTeam 3 Weather BLOG

Yesterday was an off day in the WeatherLab.  It was an off day for every meteorologist within a 100 mile radius of Lafayette for that matter.  Sometimes things change so quickly that the only way to forecast is to “nowcast”.  Wednesday was one of those days.  I predicted sunshine, and by the afternoon a large part of Acadiana was being rained on.

Normally during the month of August we’ll have at least a 20% in the forecast every single day.  That’s because it’s humid, it’s hot, and usually just the heat of the day is enough energy to get a few storms going during the afternoon.  But over the last couple of days, with a cool front passing through, the air mass had been very dry.  The dry air also allowed us to experience unusual temperatures in the low to mid 60s at night.  But there was a sharp contrast.  Only about 100 miles to our west was the front, and the humidity levels skyrocketed once you were west of Beaumont.  Along that boundary, the storms continued to fire Monday and Tuesday, and seemed to be remaining there.

Wednesday morning brought more of the same.  Dry air over Acadiana, storms that were dissipating over east Texas along the front, and pushing toward the Gulf.  The pattern was nearly identical to the weather pattern we saw early in the week.  But there was something lurking in the dry air over Mississippi.  We call it a Vort Max.  The technical term is Vorticity Maximum.  Basically this is a small spin in the atmosphere usually generated by larger systems surrounding it.  If you’ve ever paddled a canoe, you’ve seen something similar in the water.  When you pull the paddle, you will notice smaller swirls rotating around the main area of water that was disturbed by the paddle. 

These Vort Max’s can be seen sometimes on water vapor satellite imagery, and they can also be seen in the radiosonde data from the morning and evening weather balloon launches from various NWS offices around the country.  Once they’re in the computer model formula, then the effect they will have on an area can be analyzed.  But like the swirls off the canoe paddle, they’re moderately unpredictable, and don’t last very long.  If they’re not seen, or the life cycle is too short, then the models, satellites, and meteorologists will base a forecast as if it wasn’t there.  This was the case on Wednesday.  Click on each image below for the timeline and a description of what happened.

 

 

 

 

 

 

 

 

 

So we’re not 100%.  There is an off day every once in a while.  Occasionally we have to bite the bullet, but that’s the name of the game when it comes to weather.  I did hear from a few of you and your disappointment.  But at least I know you’re out there, and you are listening to what Rob and I think is going to happen.  I know if it had worked out the other way…predicting rain and then it was sunny…I wouldn’t have heard from any of you.  At least this busted forecast brought all of us together.

StormTeam3 Meteorologist Dave Baker

Good Morning Acadiana-Weekdays 5-7am!