Saturday, May 31, 2008

May 31

We started the day in McPherson, KS, and the models showed another bonus chase day. Early morning storms formed just south of McPherson and covered the ground with large hail in and around Wichita. These storms also laid out a well-defined outflow boundary across northern Oklahoma that would provide added convergence and enhanced low-level shear. A stout cap was also forecast to strengthen throughout the day and limit initiation until late evening.

We cruised south toward Wichita, ate lunch in Arkansas City, and found a park to sit and watch the weather for a while. The outflow boundary was easily discernible to our south with a long horizontal line of cumulus all along it. Within a couple of hours, it appeared that the best chance for initiation would be just to our south and west near the intersection of a frontal system and other outflow boundaries. We slid south to Tonkawa, OK and continued to wait for the cap to break.

The mid-level warm air advection didn't help matters despite the strong low-level convergence in northern Oklahoma. Still, a very subtle shortwave was noted on the meso analysis pages and was moving into northeast Oklahoma where the cap was somewhat weaker. Just after 5 p.m., towers did manage to build just to our south but were quickly knocked down because of the cap. However, continued growth to our east eventually resulted in a couple of small supercells that developed east of Ponca City.

These supercells quickly grew and within a few minutes were tornado warned. In fact, spotters and chasers were reporting a tornado with both storms. We drove east on Highway 60 through Ponca City and Burbank in an attempt to intercept the storms. The closer were got to the storms, we noticed well-defined wall clouds with both supercells that would occasionally produce funnels. A couple of problems happened rather suddenly at this point. First, we encountered hilly terrain and a multitude of trees (reminded me of Mississippi chasing). Second, the storms moved off the outflow boundary and rapidly weakened. At this point, the closest storms were in Kansas and only posed a hail and wind threat.

We called the chase off near Tulsa and drove back to Oklahoma City. As we drove toward Oklahoma City, a large supercell developed just west of the city after sunset and provided a spectacular lightning show. As we arrived to the hotel, I went straight to sleep because we planned on leaving for Starkville early in the morning.

Unquestionably, this was the most successful TIG trip ever, and we chased on all but three days during the trip and saw a total of 9 tornadoes! It was a pleasure meeting all of you and getting to know you, and I wish all of you luck in your future endeavors! If you would like to drop me a line, send me an e-mail to

Friday, May 30, 2008

May 30

We took it easy today, and didn't leave the hotel until around 11 a.m. The best chance of severe weather looked to be well east into Illinois, but we didn't want to position ourselves 14+ hours from Oklahoma City with one day to drive. The chance of severe weather didn't appear great enough for Kansas or Missouri, so we decided to check out the University of Nebraska State Museum on the campus of NU. This was a great museum that featured a little bit for everybody, including fossils, paleontology, rocks, natural history, culture, biology, and even space (right up my alley!). The coolest part of the museum was the large room of the mammoth/elephant bone collections.

After the museum, we ate at Applebee's in downtown Lincoln, and then cruised south to visit Rock City near the town of Minneapolis, KS. The 'park' consists of about 200 calcite-cemented concretions, and they even charge a $3 admission fee. This certainly didn't live up to its billing, and this will be a one and done visit for me.

We're headed back to Oklahoma City tomorrow to visit the Oklahoma City Memorial and grab a bite to eat at Cattlemen's Steakhouse. Our plans could change depending on the storms, but it appears that the main threat will be large hail and damaging winds. Low-level shear is forecast to be on the low side, and the threat of tornadoes appears quite small. Late next week is catching my eye, and I might be back out in the Plains at some point then.

You Win Some, You Lose Most

Today was a good day, but it left me with a sour taste in my mouth, especially on the last chase day of the trip. Maybe I've gotten a little greedy, but I am disappointed after today. We intercepted the Kearney storm and watched it for about 30 minutes as it was west of town. As the storm and circulation got closer to us, we decided we needed to get back east on I-80 and get ahead of the storm. As we were entering the interstate, we all saw a few power flashes in the town of Kearney, but I never saw the tornado itself. We cruised down the interstate a few more miles to get ahead of the storm, and we pulled off at an exit ramp. Power flashes were still visible off to the north, but I never could make out the tornado. Some students said they could, but I only saw the power flashes instead of the tornado.

The entire mesocyclone was extremely impressive and very well defined. In fact, this beast had the look and the environment to be a long-lived supercell that would produce significant tornadoes. Fortunately, that was not the case as another cell behind it interacted and disrupted the circulation east of Grand Island. The second supercell evolved quickly and would produce wall clouds and a few funnel clouds at times. The two storms seemed to evolve into one mega supercell and the entire system began to rotate. This reminded me of the 'Tornadocane' in North Carolina several years ago ( Multiple areas of rotation were observed, but no distinct area became dominant initially.

As the system neared Aurora, we decided to head south on Highway 14 and cut east on Highway 6. This was a slight mistake because Aurora ended up getting hit by the tornado that was on the northeast side of the storm! Yes, I said northeast side. Typically, large hail falls in the northeast side and the tornado is found in the southwest side. This was reversed with the tornado occurring in the northeast side and large hail in the southeast side. Explain that to the public if you're a TV meteorologist! Traveling south on Highway 14 also caught my eye to the discrete supercells in northern Kansas.

It was decision time at the intersection of 14 and 6. Go south to Kansas or stay on the Aurora storm? An increase in the velocity of the Aurora storm lead me to choose staying with the storm rather than going to Kansas. Big mistake. I'll let the storm reports from today explain why. This decision is why I was disappointed in myself today. Like the title of the post says, you win some and lost most in storm chasing. We had won many and lost little on this trip, so the law of averages quickly restored order to its imbalance. We got back ahead of the storm east of York, and a tornado was actually reported just south of I-80 to the east of Beaver Crossing. We have no idea where that report came from, but our vantage point showed lots of scud at the time of the report. One problem with that report is that the scud was north of I-80 rather than south of I-80 where Beaver Crossing is located. Go ahead and mark that as one less tornado report from today.

The storm weakened after this, and we headed for Lincoln for some food at a barbecue restaurant called Famous Daves. For a chain restaurant, it had some excellent barbecue! The restaurant was nearly blown down by the strong gradient/convective winds in Lincoln thanks to some storms to the south. When we got back to the hotel, I checked the radar to see multiple reports of large tornadoes in Kansas and another in southeast Nebraska. Tough day...

I hope no one was seriously injured or killed in Kearney, and the reports I've seen so far do not suggest any. Many Nebraskans can thank the cell mergers and storm interactions for sparing many towns along and just north of I-80. I'll post pictures tomorrow.

Thursday, May 29, 2008

High Risk

The Storm Prediction Center has outlooked a portion of eastern Nebraska and western Iowa in a high risk of severe weather, including the potential for strong to violent tornadoes, damaging winds, and large hail. One concern I had last night was that overnight convection could muddy the convective scenario today. Fortunately, that scenario is quite clear at this point as that convection weakened and is quickly moving off to the east into Iowa. The overnight convection was not far enough south to effectively block moisture return to northern Nebraska, and in fact, dew points in the lower 60s are just north of I-80.

Persistent strong south winds today should usher in additional moisture, and it appears that upper 60s and near 70 degree dew points are likely over eastern Nebraska this afternoon. Low-level stratus should dissipate late this morning, and temperatures should warm into the 80s with strong sunshine. This warm, moist air in the low-levels will be located beneath by very cold air aloft and will set the stage for a rather unstable environment this afternoon with MLCAPE values over 2,000 J kg-1.

As the shortwave moves out of the Rockies and into the central Plains later this afternoon, convection should begin to erupt in central Nebraska and northern Kansas. Due to the strong deep layer shear in place, these storms will quickly evolve into supercells with a threat of tornadoes, damaging winds, and very large hail. As the afternoon transitions to evening, the threat of significant tornadoes will likely increase as the wind fields and low-level shear all strengthen.

From a chasing standpoint, I've still got two target areas still. Knowledge says stay close to the warm front in northern Nebraska, but my gut is telling me southern Nebraska/northern Kansas. There is more more moisture and strong instability, good wind fields, a close proximity to the surface low, slightly weaker uplift, and high low-level shear in the southern areas. All of these factors are probably why I am thinking south at this point. I'll have pictures and a recap later this evening.

Wednesday, May 28, 2008

May 28

Today was another relatively easy day with a scenic drive from North Platte to Norfolk, NE. We were treated to a spectacular view of the Sand Hills while traveling along Highway 83. The main attraction for today was the Ashfall Fossil Beds State Historical Park ( near the town of Royal. These ashfall fossil beds were created by an enormous volcanic eruption in Idaho about 12 million years ago that shrouded much of the Plains in ash, including this area in northern Nebraska. The animals (horses, camels, birds, and rhinos) that lived during that time inhaled the ash and slowly suffocated. After their demise, they were covered in several feet of ash until they were discovered in 1991. One of the rhinos discovered was named 'Justin' and was probably only a month old when it died.

The weather today was once again chilly with highs struggling to reach the mid 50s under cloudy skies and occasional drizzle. Tomorrow is setting up to be much warmer and a potential chance for significant severe weather. A strong shortwave moves through Nebraska tomorrow as a triple point sets up in southwest Nebraska. Ahead of the dry line, low pressure center, and cold front, there should be plenty of warm and moist air to fuel the storms that form tomorrow. Wind fields, wind shear, and instability all look quite favorable for the development of supercells and tornadoes.

A couple of concerns I have at this point are moisture return and whether the morning convection can clear out, which will have a large impact on instability. At the time of this posting, it appears as though the new 00Z NAM has backed off on dew points and instability somewhat for tomorrow, especially for northeast Nebraska. This seems reasonable to me given that a large area of convection is growing in coverage and intensity across west-central Nebraska late this evening, and this should limit the amount of moisture return overnight. I expect dew points to top out in the mid 60s in this area, but regardless, MLCAPE values should be between 1000-2000 J kg-1. The timing of the storms will also play a large role in the convective evolution tomorrow. If the convection clears out of eastern Nebraska early in the morning, there should be plenty of time to recharge the atmosphere for another round of late afternoon storms. However, if the storms take a longer period of time to exit the state, this may tend to limit instability further and may shift the better threat of severe weather further south and west.

While I would hate to leave the front in north-central Nebraska, the convective setup is becoming more interesting for southern Nebraska and northern Kansas. It appears that this area will be closer to the better moisture and be less impacted by the complex of storms across northern Nebraska. While there is no discernible boundary in place (although a valid argument could be made for residual outflow boundaries possibly lingering around), a secondary surface low is forecast to develop across northern Kansas tomorrow evening. If this scenario occurs, the winds could locally back ahead of the low and provide a more favorable low-level shear environment for supercells. Additionally, the strength of the wind fields increases in the evening, and this could prolong the threat of tornadoes after dark if storms can remain discrete.

Tomorrow is quite a difficult storm chasing forecast, but I'm still leaning towards the front in north-central Nebraska (Burwell) until after watching the thunderstorm complex evolution in the morning. My backup target would be Holdrege in south-central Nebraska.

Tuesday, May 27, 2008

May 27

After a wild and exciting three days of chasing, today was an easy day of driving from Hutchinson, KS to North Platte, NE. In between, we visited the world's largest ball of sisal twine ( in Cawker City, KS and the geographic center of the contiguous U.S. near Lebanon, KS. We ate dinner at the scrumptious regional chain known as Valentino's. Sorry you weren't here Renny!

The driving weather could be summed up in one word...miserable. Skies were cloudy along with a steady drizzle and temperatures in the lower 50s. Although it wasn't quite cold enough, it almost looked like snow flakes were flying in Nebraska! For all of you back home in the South, tonight's forecast for North Platte calls for cloudy skies, drizzle, fog, and a morning low near 43. Haven't felt that in a couple of months! Temperatures look to rebound over the next couple of days with mid 80s forecast by Thursday.

The plan for tomorrow is to take care of "teaching business" and possibly drive over to Scottsbluff and Chimney Rock. Brings back memories of the Oregon Trail!

Thursday is starting to look promising again very near this area or just off to the north and east. More about that tomorrow...

Monday, May 26, 2008

May 26 Chase

The long string of severe weather days concluded on another successful note. After witnessing seven tornadoes the past couple of days, we added a couple more today in south-central Kansas to bring our three day total to 9! Today's setup appeared promising with a triple point setting up in southwest Kansas along with strong instability (MLCAPE >3,000 J kg-1) and locally enhanced low-level shear along an westward propagating outflow boundary. The atmospheric setup almost went to waste as most storms could not remain discrete. However, one supercell managed to remain somewhat discrete as it crossed the outflow boundary and produced a couple of brief tornadoes just to the southeast of Pratt. We thought another tornado formed just south of Pratt, but LDCT chasers confirmed it was a funnel cloud at that point. After the supercell moved away from the boundary, the low-level rotation quickly ceased and the storm weakened. Due to the brief nature of the tornadoes and not being able to properly work my camera, I did not capture any good images. I'll have to borrow some students' images and post them at a later time. In the meantime, enjoy the image below snapped by Mike Brown.

Tomorrow and Wednesday will almost assuredly be spent catching up on presentations and observing the geology around the area. The active pattern looks to return to the Northern Plains by the end of the week.

Sunday, May 25, 2008

May 25 Chase

After a successful Day Zero TIG Chase, we had another good day in central Kansas. We targeted the area south of I-70 and west of I-135 due to the intersection of the dry line and cold front, moderate instability (MLCAPE ~2500 J kg-1), decent wind fields, and marginal 0-1 km SRH (100 m^s s^-2). It appeared that these parameters would promote supercell development and possibly low-level rotation, especially if they interacted with any boundaries.

We saw several wall clouds, great storm structure, and a brief spin-up tornado that was attached to the wall cloud despite its landspout appearance.

My early target for tomorrow looks to be south-central Kansas, possibly near Pratt. That will be highly dependent on residual outflow boundaries and the frontal position.

Saturday, May 24, 2008

Oklahoma Tornadoes

Here are just a few pictures from today, but I'll post more and a thorough discussion in the future. Six tornadoes (two on the ground at one point) with shapes including rope, stovepipe, elephant trunk, and multiple vortex made this the best and luckiest day of my storm chase career! Off to Kansas tomorrow...

Monday, May 19, 2008

Sunset Convection -- May 18

A weak cold front moved through the Mid-South and sparked very isolated convection across parts of Mississippi, Alabama, Tennessee, and Georgia. The storms extended far enough south at sunset, so I was lucky enough to snap some images before darkness arrived.

Active weather will return to the western High Plains by the middle of this week and last through Memorial Day weekend.

Thursday, May 15, 2008

May 10 Chase

We had only one goal on this day: see a tornado. This was the day we had been looking forward to for nearly a week. A warm, humid air mass would be in place as a strong trough was forecast to eject into the middle Mississippi Valley. Derek, Tim, Todd, and I were eyeing the warm front as an initial target as low-level wind shear would be maximized very close to the front. This front was forecast to move as far north as the I-40 corridor, but we felt convection north of the front may retard its progress. Combined with a very favorable thermodynamic environment, we felt southeast Arkansas would be a good place to begin.

We left Starkville just after 10 and set sail for Winona to meet with Todd. We transferred our stuff into Todd's truck and then headed for Monticello. Before we got there, we did a quick meso analysis and everything still looked great for supercells later that afternoon. In fact, the SPC already outlooked much of Arkansas in a tornado watch through early evening. Furthermore, convection north of the warm front had slowed its progress northward, so we felt quite confident as we moved west.

Confidence quickly turned so slight caution when the 1800 UTC soundings from Little Rock and Jackson showed an impressive cap and warm 700 mb temperatures (>9 C). This was not something we had anticipated would be a problem, but we still were optimistic.

We arrived in Monticello just after 2 and camped out at a Holiday Inn. A certain set of circumstances took us into the hotel where we were greeted by a friendly clerk. We explained what we were doing, and she offered us the lobby for as long as we needed. We obliged, fired our computers up, and did a meso analysis. The thermodynamic environment looked great, but other things had changed.

The 700 mb temps had not cooled down, and in fact, were warming on the subsidence side of a short wave. Additionally, the earlier convection north of the warm front had lifted north and east, and the warm front made a northward charge as well. Not too far north, but we probably weren't close enough if supercells did develop. I still don't know why we didn't go further north with our original plan to stay on the warm front. Nonetheless, we were making ourselves at home in the lobby of the hotel and watching The Weather Channel.

4 o'clock came and went. 4:30. 5:00. Still no signs of storms or towers, for that matter. Another meso analysis revealed the same situation. Good thermodynamics. Warm 700 mb temperatures. And a warm front still on a northward march. Move north. Rather, we still held out hope that storms would fire in our area.

Just after 5:30, I went outside and noticed a few cumulus were making an attempt to go up. Would they be strong enough to break the cap, I thought? 30 minutes later revealed a resounding no. In fact, all clouds had essentially vanished minus a thick cirrus deck. Meanwhile, storms were quickly developing west of Hot Springs along the warm front. We had a decision to make. 6:30 was our cut-off to go north or go home. We decided we were out here so let's head north and see what happens. Not before the nice hotel clerk baked us some delicious cookies!

As we drove north to Pine Bluff, we noticed the storm was quickly intensifying and taking on the appearance of a supercell. Within a few minutes, not only was the storm a supercell, but it was prompting tornado warnings just southwest of Little Rock. In fact, the tight gate-to-gate couplet confirmed that a tornado warning was clearly justified. The supercell also appeared close to the warm front, so we knew the threat of a tornado was higher than normal. As we got to Pine Bluff, we headed northeast on Highway 79 toward Stuttgart.

We were quickly catching the storm and soon the base became visible. We were instantly drawn to the wide, low hanging cloud in front of us. It was a wall cloud, but something else was snaking down from the wall cloud. It was a funnel cloud! The slender looking tube was 3/4 of the way to the ground and looked like it had just lifted. We probably missed a tornado by no more than a minute. Seconds later, the weather radio confirmed our suspicions when spotters reported a tornado.

The next problem we quickly discovered was that we had no roads to navigate around the storm. We had take Highway 152 and then catch Highway 165 to De Witt. The storm was moving at 45 mph, so we quickly lost our vantage, coupled with the fact that the sun had set. Our radar still confirmed the supercell was nasty, and the warnings indicated that another tornado damaged areas in southeast Stuttgart. We took Highway 1 from De Witt to Marvel and ran across the damage path of the storm. Mostly small limbs, but there was a tree or two fallen on the road.

Navigating through this and a blinding rain took us farther from the storm. When we got on Highway 49, we quickly made up ground on the storm now in northwest Mississippi. We crossed back into Mississippi, but we had a decision to make at the crossroads of 49 and 61. Go south and avoid the storm, or take 316 and try to punch ahead of the circulation. We decided the south route was safer, so we took Highway 61 to Clarksdale. By this time, the storm had crossed I-55 and entered the thick pine forests. We didn't want to follow, so we called off the chase at this point and headed back to Winona to get my car.

This was certainly not a disappointing day, but it showed how lucky you sometimes have to be to see a tornado. I guess we were disappointed that we didn't meet our goal. After the front passed, a large trough was forecast to settle across the eastern half of the country for several days and would inhibit large severe outbreaks for the foreseeable future.

May 15 Clouds

After the large complex of morning showers and thunderstorms exited the state, sunshine broke out and heated the waterlogged ground. As this occurred, an expansive cumulus field developed and was joined by other mid and high level clouds throughout most of the afternoon.

As the sun began to set, a veil of mares' tails cirrus clouds were present in the sky along with the moon and weakening convection off to the northwest.

May 8 Chase

The day started like any other day. Alarm goes off at 7:30. Roll over. Turn on The Today Show. Everything is normal for about 15 minutes. Then, to my surprise, WTVA cuts in for a tornado warning issued for a storm just southwest of Tupelo. This piques my curiosity and I roll out of bed to fire up the computer and analyze the storm. Sure enough, this was one impressive looking supercell that formed on the northern edge of an instability axis and in an area of high low-level wind shear. Shortly thereafter, a tornado causes EF-3 damage along the main business strip in Tupelo, including the Barnes Crossing Mall. The storm continued to maintain an impressive signature until it encountered more stable air in northwest Alabama.

Tim and I watched for new storm development along the cold front entering northwest Mississippi for a good part the morning. While the storms were certainly healthy looking on radar, there were no warnings being issued, despite the storms moving into an area of increased instability (MLCAPE > 1000 J kg-1). As the line/cluster of storms got close to Starkville, we decided to jump on Highway 82 and intercept a couple of rogue storms ahead of the main line near West Point.

As we drove north on Alternate Highway 45, the storms to our northwest were certainly interesting and showed hints of a rain free bases at times. However, the storms quickly became outflow dominant on top of West Point and we were slammed with the rear flank downdraft and blinding rain. We decided to drop back south and head east on Highway 82 to get ahead of the storm. As we did, other storms near Starkville lead us to take a closer look at them. We didn't see anything impressive initially with those storms, so we trucked back east on 82 until we were just west of Columbus. We sat up at a new gas station on the Highway 45 exit and observed an impressive shelf cloud and a set of rotor clouds along the leading edge of the line. We snapped a few images and then decided to head back south to get a closer look at the storms moving out of Starkville.

As we did, these storms never really got their act together and quickly moved off to the east until they intensified in west Alabama. At this point, we decided to call off the chase because we noticed the storms weren't able to sustain themselves at a severe level for a long period of time. Our meso analysis suggested that subsidence on the back edge of a shortwave may have contributed to warming aloft and probably weakened the updraft accelerations in the storms. Nonetheless, it was a cool local chase and was worth seeing the rotor clouds. However, our attention was focused on May 10...