Significant Severe Weather Possible This Weekend and Likely Next Week

Damage in Yazoo City, Missisippi in April of 2010 from an EF-4 tornado with a path length of 149 miles

   This weekend it appears possible that the threat of severe weather may return to the Great Plains.  Things could kick off as early as Saturday and Sunday, however Monday through Wednesday seems to be much more ominous.

   Saturday may bring a chance for a few severe storms in N TX.  These storms would likely be supercellular structures, and would have the potential to produce very large hail, and less likely an isolated or possibly few tornadoes. The main question at the moment is if enough moisture will be available in the area with the greatest potential, and if the cap will be able to break before nightfall when convective inhibitation will substantially increase and likely kill off any storms that may form during the afternoon hours.

   Sunday may also pose the threat for supercells along the dryline from southcentral to southeast Kansas through Central/East Oklahoma down to Central/East Texas. This setup has much more potential than Saturday, however the cap seems to be the main question for this setup as well. Any storms that form along the dryline will likely be extremely powerful supercells, and will have the potential to produce very large hail given CAPE possibly reaching 3000+ j/kg, and tornadoes- possibly strong, due to good wind shear and the high CAPE values along and ahead of the dryline. Again, the main question is if storms will be able to develop due to 700mb temperatures being on the high side, forming a capping inversion.

   As of now, it appears a large and very dangerous tornado/severe weather outbreak is likely Monday across parts of the Arklatex reigion into Dixie Alley. This setup could potentially be the first high risk setup of 2011.  Strong wind shear of 50+ kts and CAPE values exceeding 2000 j/kg should be enough to support supercells and bowing segments capable of producing large hail, damaging winds, and isolated tornadoes. Over parts of Dixie Alley, 850mb winds could be in excess of 50+ kts, pointing out the extreme energy this system will have. This severe weather event could even effect areas as far as Ohio, Indiana, Kentucky, Tennessee, and Illinois. This could be an especially dangerous day, so people need to pay attention to what is going on. As Monday comes closer, details will become more apparent, resulting in greater confidence in the forecast.

   This system will likely continue to produce severe weather across the south into New England Tuesday and Wednesday before exiting into the Atlantic. If you live in any of the affected areas, stay tuned to later forecasts and listen to NOAA Weather Radios and local news for more details regarding this event.

Donovan Gruner

Severe Weather Expected From Central Plains to Midwest

    Severe weather including tornadoes is possible today from parts of Kansas, Nebraska, Missouri, and Iowa.  Unlike previous days, it appears that stronger forcing and lower temperatures aloft will allow for the cap to be broken. A low pressure system/triple point will move into NE Nebraska and W Iowa by this afternoon, bringing the greatest severe weather potential due to veering low level winds near the triple point to the area.

300+ 0-1 km Helicity Across much of the risk area

    Low level helicity will be maximized by low level veering winds near the triple point, bringing the greatest tornado potential to SE Nebraska, NE Kansas, extreme N Missouri, and much of Iowa.

Maximized instability near triple point

    By 19-21z (2-4 pm CDT) storms are expected to be developing along the dryline from E Nebraska down through NE Oklahoma. The greatest tornado potential will be with any storms that are able to remain discrete for a while after development. Strong forcing associated with a shortwave trough may be conducive of a more dominant bow echo mode towards evening and sunset. This will shift the primary threat from large hail/tornadoes to damaging winds, which with some large hail could persist into the night through Iowa and N Missouri into Illinois. This system could also bring significant severe weather to parts of the East Coast tomorrow.

   Later in the week could bring more severe weather from parts of the southern and central plains, bringing more opportunities to chase Thursday through the weekend.

Donovan Gruner

SPC Tornado Probs

March 8th, 2011 N Texas Storm Pictures

First lightning shot of 2011!

   Another chase opportunity before heading home for spring break.  Headed out from Norman a little after noon (later than planned) and set a target of Sherman, TX to allow a little cushion to the west, since I expected storms to initiate just west of I-35 in N Central Texas.  Because of the late start, had to play catch-up with the storms as they developed slightly earlier than I had anticipated.  Once I finally caught up, it didn't take long for stuff to get interesting.

First hailstone to hit me in the noggin in 2011

   The first storm I got on was actually originally just a core punch to get into position for a more southern cell I was interested in.  Shortly after I began driving into the storm, the NWS slapped a Severe Thunderstorm Warning on it.  It produced gobs and gobs of dime to nickel sized hail, and torrential downpours.  After a while, stuff started looking more interesting on radar, so I decided to stick with it for a bit.  Eventually, I got into what there was of a "bears cage," and found a decent lowering.  It, however, did not appear to have much, if any, rotation at this point.  Within ten minutes of that, there was a rapidly intensifying couplet nearby, and giant hail began to fall.  The stone pictured above is the one that hit me in the head while trying to pick up a bigger stone from my open car door.  Some were around 2.5 to 3 inches, judging by what I could see on the ground.  One managed to put a small crack in my windshield, but luckily no more than just a small crack.  Also experienced some extreme winds, likely associated with a tornadic circulation/RFD, just to the west of Paris, TX.  There was a bit of damage done in the area of Paris to a small farm house and a barn. At this point I decided it would be too dangerous to continue being there was no paved roads to get further south of the storm, and it appeared to be completely rain-wrapped. If storms had stayed more discrete, there is no question in my mind that there could have been several more tornadoes, and a much better chase opportunity.

 

Pictures from the February 27th, 2011 Northern Oklahoma Supercell

   Last week we headed out to N Oklahoma for the first chase of 2011.  Rang in the new chase season with a beautiful supercell that formed in NW OK and moved along a warm front into S C KS.  This storm produced a tornado near the OK/KS border just east of I-35. Unfortunately due to bad roads, we were unable to keep up with this beast being it was moving between 50-55 mph at that point. All in all, it was a great day to start off the 2011 storm season.

Storm Reports from 2/27/11