WKU Meteorology

Much of Kentucky saw torrential rain yesterday which led to flooding across parts of the Bluegrass. An impulse of energy swept through the region yesterday evening into the overnight hours bringing isolated severe weather. Gusty winds led to down trees and a few power outages near Louisville and flash flooding resulted from a shield of rain with embedded, heavy rain producing thunderstorms moving slowly across central Kentucky. Once the westward moving outflow boundary interacted with the line of storms coming from the northwest, the rain began to move south more rapidly. The storms started to dissipate before reaching the Bowling Green area around 2 am.

Radar loop of Saturday and early Sunday’s storms

The rain cleared out early this morning allowing the heat and humidity to filter back into the area. Expect highs to top out around 85 degrees today with an isolated shower chance due to daytime heating. Another disturbance over Southern Illinois will begin to work it’s way into the region late this evening into the overnight hours, bringing with it a 40% chance of showers and thunderstorms. A slight risk for severe weather exists over the southern portion of Illinois near the outflow boundary. Although severe weather is not likely this far south, any storm development over that region will drift southward overnight.

A 30% rain chance will linger into Labor Day, but as we head into the afternoon hours, the rain chances will begin to diminish. Expect partly cloudy skies with a high near 86 degrees. A cold front will sweep through the region tomorrow evening, helping temperature to dip into the low to mid 60s by tomorrow night and providing much more comfortable conditions for the following days. We will struggle to make it out of the 70s Tuesday as a we look to end up around 79 degrees late afternoon. You will need a jacket if you plan on being out and about Tuesday night as the low temperature will be in the mid to upper 50s.

Weekly outlook:

Wednesday: Sunny, with a high near 81.

Wednesday Night: Mostly clear, with a low around 60.

Thursday: Mostly sunny, with a high near 84.

Thursday Night: Mostly clear, with a low around 62.

Friday: Mostly sunny, with a high near 86.

Friday Night: Mostly clear, with a low around 63.

Saturday: Sunny, with a high near 87.

Today was the last day of our trip in the central plains.  We started the day in Ada, OK.  We did not have a regular forecast discussion, because we as a group did not know if we were going to chase today or not.  We wound up discussing whether or not we were going to chase in the van.  We decided that if we were going to chase, we would head towards Piedmont, OK.  After about an hour or so of weighing the pros and cons of chasing, we decided that it would be in our best interest to not chase and to go ahead and head back to Bowling Green, KY.      We chose not to chase for several key reasons.

The first reason is that due to time constrictions on the van. It would be nearly impossible for us to have chased and then get back to Bowling Green before our deadline for the van.

Another reason is that the topography of our target area is full of hills and trees, so that we would only be able to see the storm for a few seconds at a time.

Another reasons is that there would have been a lot of storm chasers trying to target the same storms that we would target.  This would have added another potential threat to an already dangerous situation.

The final and main reason we chose not to chase was due to the fact that these storms were forecasted to initiate over or move into highly populated areas.  One of the things that we try to do on this trip is to avoid, if at all possible, areas where serious damage could occur and areas that have already been hit by a tornado.  This reason fits with our target because there was a risk for severe weather, and potentially tornadoes, in the same areas that the EF-5 tornado damaged last week.

So with all of those reasons in mind we left Ada, OK between noon and 1pm and reached Southaven, MS by about 8 pm or so.  After we dropped of Dr. Dixon, we then headed off to Bowling Green, KY and got there between midnight and 1 am.  We then rinsed off the van and went our separate ways.  We will be resuming the class portion on Monday so we can compile all of our photos and collect the radar data from the storms we chased.

Day 12 started off with a forecast discussion in Weatherford, OK. There was a moderate risk issued for parts of south central Oklahoma into central Kansas. The original target was for Stillwater, OK. All of the needed ingredients stacked up over that area. We had plenty of synoptic scale lifting from the upper level winds. There was a sufficient moisture axis with dewpoints in the upper 60s. CAPE values for the area were in the range of 2500-3000. Along with that, there was relatively no cap. The environment was great for storms. However, as we were leaving the hotel, we noticed storms firing up just to our southwest. We made the decision to go and at least check those storms out. The supercell we stayed with did not produce a tornado, but it did provide some beautiful structure as it was a low precipitation supercell.

This is what we saw for the majority of the day. We stayed with the southern supercells and ended the day watching a lightning show as the storms dissipated.

Photo by Tyler Smith

We began the morning in Andover, KS.  The SPC had issued a moderate risk over much of the eastern panhandle of Texas into parts of western Oklahoma, and extended up slightly into southwestern Nebraska.  After our morning discussion we decided to head towards the Woodward, OK area.

Surface analysis for 7:15 a.m.

Upper level wind speeds were favorable along with sufficient moisture, lift and instability across the area near Woodward.  However there was the chance that storms could become linear as some of the large scale lift and moisture convergence slightly hinted at this, which would decrease the chance for any isolated supercell development.  This seemed to be the case as we headed towards Wheeler, TX around 3:30 pm and spent most of the day staying ahead and observing this squall line.  The cell we were observing had a tornado warning but did not last long as it lost rotation strength fairly quickly.  We stayed with this storm for a while as the structure was still pretty nice looking.

As this storm seemed to lose intensity we moved out of position to look over data a little while longer until we noticed a cell just south of Elk City, OK.  As we arrived on this cell it was tornado warned for a short while before losing strength fairly quickly.

This was a screen shot of the base reflectivity and base velocity of this storm just after the tornado warning lifted.  There was still some rotation as you can see with the couplet in the velocity image, however nothing dropped as the rotation lost strength.

We finally started heading back towards the hotel for the night and around 9:05 pm there was a possible, brief sighting of a rope tornado near New Cordell, OK.  There is still no confirmation on this tornado so as of now it is just speculation.

Today was a fairly busy day driving with high expectations as the SPC had painted a good chance for severe storms.  We did not encounter any extreme supercells, though we did still see some excellent structure and observed a couple storms as they were tornado warned.

We started the day in Salina, KS after staying there overnight and catching much needed rest from the previous day’s chasing. As is usually the case we met at 9 am for a forecast discussion led by one of the students on the possible areas of severe weather. The Storm Prediction Center had outlined a very larger area under a “Slight Risk” of severe storms which extended from Texas to Wyoming and from Kansas to Michigan. When forecasting for a target area for our group to chase, the area can’t be half of the US and thus we must look more closely at the conditions needed for severe weather and narrow it down to choosing the best area. Morning surface analysis of current weather conditions offers a good deal of insight into where our target will be.

Surface analysis valid for 8:15 am overlaid with forecast 500 mb winds (purple arrows) and 850 mb winds (light blue arrows). Surface analysis by Ryan Difani.

At around 8 am an a analysis of the surface revealed a low pressure system located in south-central Kansas just east of Dodge City with a dry nose of air pushing in toward the low from the southwest. This dry nose can often be the focal point for thunderstorm initiation however in this case the dry nose was well mixed until pushing all the way back to NE Texas where the dryline was located. A well-mixed dry nose is less likely to initiate thunderstorms. The analysis also indicated very warm moist air moving north (green arrows) from Oklahoma and Texas into central Kansas near the low pressure. The 500 mb (purple arrows) and 850 mb (light blue arrows) winds forecast by the computer models was overlaid on the surface analysis to better locate a target. Upper level support is essential for thunderstorm development and maintenance and especially for severe thunderstorms as the upper level winds will create wind shear. At 500 mb the strongest winds were located in NE Colorado/Panhandle of Nebraska which was closer to the main upper level trough. Then there was also a general 500 mb flow from west Texas across Kansas and into Iowa. At 850 mb  a low-level jet would be present into the panhandle of Texas and also flowing from central Texas into Oklahoma and turning east through southeast Kansas. When overlapping all of these features needed for severe storms and also forecast helicity (a measure of the ability to maintain a rotating updraft) a few targets we’re becoming apparent. One being in northeast Colorado another being in the panhandle of Texas and finally the one that appeared most promising to us (plus we we’re already there) was in the Salina, KS region. There was an upper-level disturbance (vorticity maximum) that was pushing through Kansas that was going to provide enhanced lift in this region as well which was clear on the morning visible satellite imagery.

With our target city being the city we stayed overnight in, there was no rush and the group actually took things easy at the hotel until noon. Then after eating lunch the group enjoyed some time outside at Kansas Wesleyan University while waiting for storms to fire. By 4 pm there was a rapidly developing thunderstorm off to our northeast that dropped a tornado by 4:30. This storm was out of our reach and in an area of trees and hills which we don’t desire to chase in. This storm was an indicator of the kind of environment we we’re near though which was obviously conducive to rotating supercells. Then by around 5 pm we we’re keeping a close eye on a developing storm that was poised to move right past us in Salina and once the storm appeared to be gaining strength we moved a few miles north to the town of Bennington. This rapidly developing thunderstorm developed a funnel cloud just west of Bennington by 5:30 pm. It was confirmed by other spotters that the funnel did touch down and thus was a tornado.

Funnel cloud which was a confirmed tornado (via other spotters) just to the west of Bennington, KS. Photo by Ilea Schneider.

We then re-positioned ourselves on a dirt road about a half mile east and slightly south of Bennington. By this time a rapidly rotating wall cloud was ongoing and tornado development appeared again likely.

Rapidly rotating wall cloud just west of Bennington, KS. Photo by Andrew Schuler.

At around 5:46 pm the tornado touched down just west of Bennington and quickly grew to a large wedge tornado that was likely around a half mile wide at times.

The wedge tornado that was just west of Bennington, KS. Photo by Ilea Schneider.

Photo of the WKU students observing the wedge tornado just west of Bennington, KS. Photo by Dr. Josh Durkee.

The wedge tornado still just west of Bennington, KS beyond a wheat field. Photo by Andrew Schuler.

What was most interesting about this tornado is that it was nearly stationary and only slightly moved (less than a couple of miles) for it’s entire life cycle which lasted around ~35-45 minutes. The below radar loop from ~5:45 to ~6:15 of the supercell demonstrates this (click for image for loop). The left panel is storm relative velocity which gives an indication of the winds within the storm. The bright green and bright red colors side by side just west of Bennington are indicative of a strong circulation; this was indeed the tornado. The right panel is base reflectivity with the classic supercell with a hook which is also indicative of the circulation/tornado. Our location is indicated by the small white circle and dot. This loop was compiled by and courtesy of Dr. Grady Dixon from Mississippi State University.

The tornado often went in and out of the sight as rain sometimes obscured our view. We lost a visual of the tornado for the final time between 6:15 and 6:30 when the tornado became wrapped in rain and then we moved to make sure we would not be hit by any hail.

The partially rain obscured wedge tornado. In this photo the southern edge of the tornado can be clearly seen but the northern edge is difficult to differentiate from the rain. Photo by Andrew Shuler.

We pushed east, south and finally back west on I-70 to gain a better view of the storm. We moved north again to toward the base of the storm around 7:15 and some rotation was noted off to our northwest next to a colorful precipitation shaft. The rotation soon weakened and we decided to move south toward our hotel and possibly intercept another storm along the way.

Rotation could be noted on the left side of this image while the precipitation shield displayed a blue/green color. Photo by Andrew Schuler.

The other storm remained weak and thus we continued to push south to our hotel in Andover, KS just outside Wichita. We of course hoped that no one was being affected by this tornado and we are happy to report that no deaths or injuries resulted from the tornado and that there were only few structures that were damaged.

We conducted our forecast discussion in the morning and left North Platte, Nebraska. Our target area was Smiths Center, Kansas which is extremely close to the geographic center of the conterminous United States!

Photo by Veronica Hall

We stopped at a park or two to throw around a Frisbee and catch up on some sunshine. Initiation of storms began around 6pm and we chose a storm to the south versus one to the north due to chaser convergence. The northern storm had a tornado touch down, but was hardly visible due to rain obstruction. The southern storm was smaller, isolated, and relatively quite. We headed back to the hotel and chowed down on local specialty pizza in Salina, Kansas.

Photo by Veronica Hall

We kicked the day off in Spearfish, South Dakota and headed southeast toward the Badlands for a little sight seeing on our way to our target location.

Photo by Andrew Schuler

We initially planned to head to extreme southwest South Dakota, but as the day progressed and new data came in, we decided to head more toward northwest/ north-central Nebraska.

Photo by Ryan Difani

The main severe weather threat being large hail, damaging winds, and an isolated tornado. We arrived in Thedford, Nebraska around 5pm and began waiting for storm initiation. A cell fired up just to the east of us around 6pm. The storm intensified rapidly but remained relatively stationary. Incredibly strong inflow continued to enhance the storm by pulling in warm, moist air.

Photo by Colton Lindsey

We found a good viewing location for the storm, but were forced to head south once we began being pelted by hail. Internet access and cell phone service was nearly absent throughout much of the chase, forcing us to blindly navigate away from the hail core and southwest corner of the supercell where the radar indicated a possible tornado. We found ourselves trying to maneuver deep sand back roads and encountered several dead ends. Finally we made it back to a paved road and were able to gain a signal for the radar. The supercell had been downgraded to a severe warned storm, so we headed about 20 mile south to another storm with better rotation. By then it was already dark and the storm didn’t look overly impressive, so we pulled off the road and enjoyed the amazing lightning show.

Photo by Tyler Smith

After the lightning drifted too far for viewing, we headed back to our northwest toward the previous storm that was still cranking out quite a lightning show. We ended up off the main road in a windmill farm watching the beautiful flashes of lightning illuminate the mammatus clouds.

Photo by Tyler Smith

Photo by Tyler Smith

After about 45 minutes we headed toward North Platte, Nebraska to our hotel. We arrived around 12:30am and within minutes everyone was snoozing.

We woke up in Ogallala, NE with a slight risk from the SPC covering from western Montana down into Kansas, with large hail being the main threat although tornadoes were still possible. After the usual morning discussion we decided to head to our target area around Spearfish, SD.

As we approached Sturgis around 2 the first storms started to initiate just to our north. The cell we were initially on began to fall apart rapidly but recycled itself, just as it continued to do for the rest of the afternoon. We ended up staying on the same quasi-stationary cell for 7 hours, traveling only 50 miles to stay with it!

Photo by Colton Lindsey

With each recycle, the supercell became more structured with hail up to 2.5 inches.

Photo by Colton Lindsey

At times the RFD would dominate the cell causing it to gust out.

Photo by Colton Lindsey

Photo by Colton Lindsey

We chased the cell until we ran out of road to safely navigate with it, so we set up to watch the storm pass as the sunset behind it.

Photo by Colton Lindsey

With the passing of the storm we were able to see the entire updraft as it was illuminated by the sunset. Dr. Durkee was able to capture some amazing pictures of this almost surreal set up.

Photo by Josh Durkee

After this photogenic storm day we headed back to Spearfish to our hotel to set up for the next day.

We left Amarillo, TX at 9 this morning after a quick forecast discussion in the van, with a destination in Northeast Colorado to watch initiation. We ended up in Holyoke, CO and followed a storm onto the border of CO and NE, which lost strength. We then drove to the Ogallala, NE area and saw amazing mammatus clouds and an also amazing lightning show! Goodnight from Ogallala, NE!!

We woke up today and had our forecast discussion in Lubbock, TX.  We all did a surface analysis

for where we thought our target was going to be.  After the discussion, we all agreed that the area from Lubbock to Childress to Amarillo, TX was going to be the best area for severe weather.  We headed out and stopped in Paducah, TX for lunch and ate at a little hole in the wall drive in.  Our orders took longer than we anticipated, due to the fact that they did not have anything prepared.  By the time we all got our meals, thunderstorms had already initiated northeast of Floydada, which was about an hour away to our west.  We got there once it went severe, even tornado warned.  Despite the warning, this storm did not appear from our vantage point to put down a tornado.  This storm did have a strong inflow, which ingested a lot of dust from the surrounding farm land.  This storm ingested so much dust that the rain from this storm also had mud imbedded within the rain drops.  The outflow of this storm also kicked up so much dust that it caused blackout, more like orange-out, conditions

Approaching dust heavy outflow from storm. Photographed by Andrew Schuler.

to where we had to pull off the road and wait for it to pass.  We also saw plenty of land spouts,

Land spout photographed by Andrew Schuler.

gustnadoes,

Gustnado photographed by Andrew Schuler

and dust devils.

Dust devil photographed by Andrew Schuler.

We left the storm later due to the fact that it lost its rotation.  By this time, we were near Spur, TX and we changed our mindset from chasing to eating. We decided to go to the Big Texan in Amarillo, TX

Store front of the Big Texan restaurant. Photographed by Andrew Schuler.

for dinner and while we were there, we witnessed someone take on and complete the 72 oz. steak challenge with only 13 seconds left in the hour long challenge.  With bellies full of steak, we all headed our hotel and rested for what is going to be another day of chasing.