KATC StormTeam 3 Weather BLOG

“Hole Punch Clouds” were seen across much of Acadiana’s sky this afternoon.  Thanks to many viewers I received some great shots of holes and lines punched through the cirro-form cloud deck that was located at 23,000ft earlier today.  The satellite imagery really showed numerous hole punches across the region all the way back through Texas spanning into Arkansas too.  I had to play forensic meteorologist this afternoon to determine exactly how these formations were induced.  I have seen the phenomenon before, but had never seen it show up so dramatically on the satellite shots too.  The NWS in Pensacola has a nice description of similar cloud formations that were observed in 2003.  From there I looked at today’s upper air sounding that showed our cirro-form cloud deck at 23,000ft.  Just below that deck was super dry air.  Temperatures at this level were in the minus 25-30 degree range.  The satellite imagery indicated that most of the formations originated in Texas and were carried in the winds aloft while the formations broadened.  Basically jet aircraft that crossed this deck, and most probably descending craft, initiated perturbations in the atmosphere that allowed a “supercooling” of the air parcel that was dragged downward by the aircraft.  As supercooling occurred, ice crystals formed and while the ice crystals formed, evaporation surrounding the ice crystals produced the circular pattern.  In some spots you could see the cirrus ice crystals in the center of the circles, while other circles were void of any cirrus crystals.  Also, noted on the 18:15 gmt imagery (12:15pm our time) you can clearly see circles in Evangeline, Allen and moving into Lafayette parishes.  While at 20:01 gmt imagery (2:01pm) you can see numerous holes to the north and also lines where aircraft spent longer time in and near the cloud deck at 23,000ft.  Cool stuff! 

Weather wise, expect plenty of light to moderate rain tomorrow, a break on Wednesday, and more rain and thunderstorms likely for Thursday.  The Thursday weather system will likely be more of a trouble-maker with heavier rains (better than 2 inches) and a slight risk of severe weather possible.  At least the weekend is looking cool and dry!