I was not expecting much out of this day as it was looking like the weaker severe weather day of the first 3 days of May for the Upper Midwest.  However, I had vacation with no obligations and decided to wait at my parents in southern MN for anything to develop along a remnant outflow boundary that had pushed south to near the MN/IA border from morning convection to the north.  I thought about leaving in the morning and heading south towards the main synoptic front that had settled in near the IA/MO border, but the tornado threat did not look all that great in my opinion, and I thought my chances for seeing at least severe weather were just as good close to home.

Around 2pm CT, a lone storm first developed near a remnant boundary intersection just to the north of Emmetsburg, IA.  I jumped all over this storm, heading south on I-35 and then west on Hwy 9 and then continued west out of Forest City on Cty Rd A42, intercepting the storm near Bancroft.  The storm was developing in an environment characterized by MLCAPE values near and exceeding 1000 j/kg and effective bulk shear on the order of 25-30 knots.  A subtle shortwave was also noted on water vapor, per the mesoscale discussion issued by SPC at 2:12pm, that likely led to the isolated thunderstorm development.  The MD also highlighted that severe hail would be possible, yet isolated enough that a watch may not be needed.  A watch was never issued for this event.

Upon reaching the storm, it was apparent that the storms were going to be very slow-moving and easy to keep up with.  I proceeded to drive back and forth, in and out of the hail core of this storm on Cty Rd A42 for several hours, mainly experiencing an abundance of dime to nickel sized hail and intense rain/hail rates.  Some of the more intense hail I experienced right in the town of Forest City where there were reports of isolated hail near quarter size.  The storm picked up speed a bit and, as you can see towards the end of the video below, I encountered some very intense winds from the storm near the intersection of 310^th St and Grouse Ave about 4 miles north of Clear Lake.  I continued to follow the storm east, moving right along the intense hail core, to near Osage before leaving the storm as it was quickly losing intensity as it moved into more stable air.

One of the few photos I took from the day as I focused more on video.  Intense hail core ahead of me after I just crossed I-35 on Cty Rd B20/300th St to the north of Clear Lake, IA.

Storm forming a ragged shelf cloud as it began to weaken to the southwest of Osage, IA.

OUTLOOKS:

REPORTS:

After seeing a tornado near Sedan, MN the day before, MaryLynn and I chased the following day in southern MN.  This was kind of an odd set-up kind of day as convection from the night before diffused a synoptic stationary front that settled near the MN/IA border on the 2^nd, while additional, small scale boundaries were leftover from the previous night’s convection as well.  Even though there was a Moderate Risk in place across eastern NE and far western IA, I thought much of this would come after dark in the form of large hail and damaging winds from an overnight MCS.  I chose to play the Slight Risk area across southern MN/northern IA instead.  There was broad southwest to northeast flow aloft with a weak upper level trough in place and, consequently, a belt of 50 knot flow at mid-levels that led to effective vertical shear on the order of 45-55 knots, sufficient for the development of supercell thunderstorms.

I decided to head down to Clear Lake, IA where I thought the synoptic boundary had settled during the day as very unstable conditions developed in the area with 100mb MLCAPE near 2000 j/kg.  We checked out the town and the famous Surf Ballroom (https://www.surfballroom.com/), and then went to a park near the lake to wait.  At 3:34pm CT, a mesoscale discussion was issued for areas from northeast NE into northwest IA and southern MN, highlighting the risk for severe thunderstorms, possibly supercells, and a low end tornado risk for areas along a developing warm front and other subtle boundaries.   We started to progress back north on I-35 towards Albert Lea, while a storm began to develop in the vicinity of St James shortly before 5pm and a severe thunderstorm watch was soon to follow, issued at 5:30pm.  This was right on the developing warm front so we made our way west on I-90 and then north on Hwy 169 where we intercepted this storm near Lake Crystal.  The storm had a large base underneath the nicely vaulted updraft and began to produce a wall cloud upon approaching Lake Crystal.  There was a lot of motion all over the place at this point with numerous areas of inflow and outflow, even some rotation, but nothing that concerned me that there was an immediate threat for a tornado.  We followed up Hwy 169 into the southwest side of Mankato where the storm seemed to go from an organized base, possible wall cloud, to more of a shelf/outflow looking feature.  We then somewhat cored the storm upon going east on Hwy 14 on the northern side of Mankato.  At this point, we encountered nickel sized hail with some quarter size mixed in.  As we made it towards Eagle Lake, the storm was about to undergo a cell merger from a newly formed storm coming up from the south.  As you can see in the photos and video below, we witnessed a funnel shortly before or near the cell merger somewhere off of Cty Rd 17 to the east of Eagle Lake.  This lasted for only a couple minutes but it was a little nerve-wracking since the funnel was coming right at us.  Quite the exciting experience though!

We continued to follow the storm on Hwy 60 through Elysian and Waterville and then southeast on Hwy 13, then east on Hwy 66/12 towards Medford.  From Elysian over to Waterville, we encountered a lot of hail that had piled up on the road and made for slow travel.  There was even quite a bit of ice fog that had formed from the melting and reduced visibilities at times.  It was quite the spectacle with this raging thunderstorm going on just to our northeast as we followed.  The storm did produce another couple of lowerings through the duration and an apparent wall cloud as the storm became better organized near Medford.  But as we approached Kenyon, the storm became outflow dominant and bit messy.  This is where we called things off for the day and then had short trip back down to my parents for the night.  One of the shorter drives to our final destination that I’ve ever had after chasing!

Lowering forming underneath the updraft to the west of Lake Crystal, MN as we approached from the south.

Another view of the lowering underneath the vaulted updraft on the storm west of Lake Crystal.

Fairly fast condensation into the lowering occurring on the southwest side of Mankato off of Hwy 169.  Core of storm to the right.

Funnel forming on the storm just to the east of Eagle Lake, MN on Cty Rd 17.  Shortly before or near the time when a cell merger was taking place.

Another shot of the funnel to the east of Eagle Lake.

Hail covered roads near Elysian, MN on Hwy 60.

Hail drifts between Elysian and Waterville, MN on Hwy 60.  Notice how covered the field is in the distance.

Hail fog forming off Hwy 13 southeast of Waterville, MN.

One of the interesting lowerings we saw on Hwy66/12 as we approached Medford, MN.

Storm producing a roll cloud as it became more outflow dominant south of Kenyon, MN.

Another view of the storm starting to gust out to the south of Kenyon, MN.

OUTLOOKS:

STORM REPORTS:

This chase involved an early season close-to-home setup across MN.  A Slight Risk for severe thunderstorms and a 5% probability for tornadoes had been issued by the Storm Prediction Center across much of the state.  An upper level trough and jet streak was moving into the Dakotas as the day progressed, while an area of low pressure developed across northeast SD and a warm front lifted north into eastern SD and west-central/southwest MN.  Meanwhile, a cold front was advancing through eastern SD and NE.

MaryLynn and I left from my parent’s house in southern MN that morning.  I was rather torn on a target area, either heading north towards the triple point that would be approaching “The Hump” area of western MN, or head towards the higher instability along the cold front near Sioux Falls, SD.  We chose to angle our way up through western MN and I finally decided to go to the northern target upon reaching the New Ulm area.  We opted to head for Sauk Centre, which was north of the warm front, but just east of the area I thought storms would initiate.  Shortly after we arrived, a mesoscale discussion was issued by SPC, highlighting the need for a Watch to be issued from west-central MN down to northeast NE.  The environment was characterized by temperatures in the mid to upper 70s just south of the warm front, dewpoints in the upper 50s to low 60s, steep lapse rates, 1000-1500 j/kg of MLCAPE, and backed low level winds along the warm front, although quickly becoming veered after the frontal passage.

A Tornado Watch was issued at 3:00pm from western MN into southeast SD and northwest IA, valid until 10:00pm.  Near and shortly after the watch was issued a pair of supercells developed in our area, one cell near Morris and the other I believe in the vicinity of Litchfield.  We chose to go after the Morris storm, which was fast approaching the Glenwood area.  As we neared the storm, it was quite intense with a lot of lightning and a well defined hail core and even a base attempting to form underneath the updraft on the southern flank of the storm.  I did not think this storm was looking the best, so I wanted to get out ahead of it and head east.  As we did so, I looked behind us and, low and behold, there was a funnel protruding out the front of the large, ragged base!  This did end up touching down near the Sedan/Brooten area with additional spin-ups underneath the base of the storm for about 10 minutes thereafter.  It was interesting because this was a broad action area and seemed to be fairly disorganized at the time.  I was surprised that it produced a tornado at this point as it did not have that real good look and was fairly high based.  After calling in the tornado, we continued to follow the storm through the St. Cloud area where it produced several wall clouds and transitioned into a beautiful mothership appearance just east of town near Santiago.  The storm had a large, rotating mesocylcone at the time and was quite photogenic, as you can see below.  Shortly after the storm became more outflowish and we called it a day around 6:30pm.

Lowering forming underneath the updraft base on the storm east of Glenwood, MN.  Rain/hail core to the right.

Intense hail core on the storm east of Glenwood, MN.

Tornado touching down near Sedan, MN.  Debris cloud to the left of the image.  Notice no well defined wall cloud but certainly a clear slot cutting in behind this tornado.

Big lowering underneath the storm and continued spin-ups occurring after the tornado near Sedan, MN.  Thought at first these were gustnados, but think these may have been weak tornadoes occurring underneath the action area.

More debris areas kicking up underneath the action area/broad lowering underneath the storm between Sedan and Brooten, MN.

Wall cloud tightening up near St. Joseph, MN, approaching St. Cloud with the sirens blaring at the time.

Awesome mothership appearance to the storm east of St. Cloud, MN near Santiago.

Another view of the awesome storm near Santiago, MN with large mesocyline underneath.  Kept trying to produce wall cloud looking features on the right (northern) side of this storm.

OUTLOOKS:

STORM REPORTS:

This was supposed to be the big “day after the outbreak” severe weather event across the Upper Midwest, which ended up being a lot less severe than what most were thinking.  The set-up included an area of low pressure near the Sioux Falls, SD area around midday that was traveling along a warm front that was lifting into south-central MN.  There was also a mixed out dryline/cold front that was moving to the east through southern MN and IA through the afternoon.  The environment ahead of this system and south of the warm front was characterized by temperatures in the 70s, dewpoints in the upper 50s and 60s, upwards of 1000-1500 j/kg of MLCAPE, and 50-70 knots of effective bulk shear.

I had plans for much of the afternoon and was not sure if I would be able to chase or not, but the storms held off until the late afternoon to reach the Twin Cities area so I was able to head out.  I didn’t think we needed to go very far since the Twin Cities is where I thought there would be the best chance to see a storm produce a tornado due to the warm front lying right across the metro area with better backed surface winds.  A tornado watch was issued for the area at 3:40pm highlighting the tornado risk due to the unstable environment, intense vertical wind shear, and the very strong winds aloft.  A few storms in the vicinity of 5pm became tornado warned around 30-40 miles west of the Twin Cities and produced a couple of weak tornadoes right on the triple point, which we did not see.  MaryLynn, Sheena McLain, and I traveled south on I-35 out of Burnsville to intercept a couple storms that were moving up towards the area from the south.  We got on the first storm near New Prague and then followed it up highways 21, 169, and 41 through Chaska towards the southwest side of the Twin Cities metro.  At this time (5:54pm), the Storm Prediction Center issued a mesoscale discussion highlighting the increased tornado risk near the Twin Cities.  The storm became better organized as it approached the warm front and developed a non-rotating wall cloud as we followed parallel to the storm on I-494 and then east on I-394 to get back out ahead.  The storm interacted with the warm front right near downtown Minneapolis and this is where the storm looked the best with a better defined non-rotating wall cloud and more rapid condensation into it at that time.  The inflow tail was very low and appeared to only be a few hundred feet off the ground at this time as it moved into northeast Minneapolis.  There may be some that were questioning if this was indeed a wall cloud over downtown or just a shelf cloud at that time.  I would argue for a wall cloud that transitioned into a shelf as the storm became more outflow dominant upon moving further north and east.  The reason I’d argue for a wall cloud is, quite simply, because it looked like one and had fairly fast condensating air into it at the time it was interacting with the warm front (see pictures below).  After the storm moves into the eastern part of the metro area, it gusted out and produced a ragged shelf cloud towards sunset.

Lowered base on the storm looking southwest near the highway 212/I-494 interchange in Eden Praire, MN.

Storm over downtown Minneapolis.  This was the non-rotating wall cloud with fairly quick condensation into it at this time.

Another view of the non-rotating wall cloud and condensating inflow scraping the ground near downtown Minneapolis.

Storm starting to transition to more outflow dominant near Arden Hills, but with continued inflow tail into it.

Shelf cloud in North St Paul towards sunset.

More photos from this day can be found here:  http://www.flickr.com/photos/39991047@N02/sets/72157629473913578/

Outlooks: 

Storm Reports:  

There was a lot of hype leading up to this event with the Storm Prediction Center (SPC) issuing a moderate risk on Day 3 and high risks on Days 1 & 2.  This was all for good reason as a deep and strong upper trough was set to eject out of the Rockies and lead to a volatile weather situation with a risk for long track tornadoes, extremely high winds, and large hail with any storms that would materialize through much of the Plains from TX to NE.  The set-up included an area of low pressure centered across northeast CO with a warm front lifting to near the KS/NE border and a dryline extending south of the low into western KS.  These fronts were expected to be the focusing mechanisms for an outbreak of severe weather and tornadoes, especially right near the warm front and in the warm sector ahead of the dryline.

Wes Hyduke and I left Burnsville the day before and stayed in Omaha, NE for the night, fully expecting to have to drive west into NE the next day.  We awoke to thick fog and low stratus and realized the moisture had returned and we were clearly north of the warm front.  The system had slowed down from previous days and we realized that we had to position further to the west, so we left early and drove on I-80 to Grand Island, NE to reevaluate there.  Towards the noon hour, convection already started to break out across western KS and quickly move to the northeast.  A PDS tornado watch was issued 10:45am as a result of this first round of convection developing due to a strong low level jet in air that was already unstable as noted by the 1500-2000 j/kg of MLCAPE  and 40-60 knots of effective bulk shear.  We decided to head south on Hwy 281 out of Grand Island to meet up with these initial storms near Nelson, NE.  These storms had been tornado warned but the main threat was large hail and the storms were already starting to congeal into a cluster as they moved northeast into NE.  These were not impressive looking enough to keep us on these storms as we thought the main show would be later in the afternoon along the dryline.  A mesoscale discussion was issued at 1:41pm highlighting this risk across southwest NE into northwest KS.

As more intense supercells developed along the dryline further south in western KS and western OK, and were quickly becoming tornadic and cyclic, we almost decided to bail on our northern area and head to the northernmost cell approaching the Great Bend, KS area, which later produced a long track tornado that passed very close to Salina, KS.  This area had extremely high storm relative helicity and had MLCAPE approaching 3000 j/kg.  We decided to stay north on the dryline as there were some cells starting to get going and thought we had just as good of a chance to see a tornado here, although in an environment that was less unstable than further south.  These storms were slow to develop for some reason, but one storm did manage to break through and intensify.  This was our storm.  We traveled northwest from Alma, NE towards Oxford.  The storm was looking better and starting to get some incredible structure and fast, albeit cool, inflow air with an impressive tail cloud into a lowered base.  A wall cloud soon developed around 4:30pm and we witnessed a rope tornado for around 3 minutes near Oxford at 5:18pm.  After the tornado died, we followed the storm on Hwy 34 northeast in hope of the storm producing again, but that ended up being the only tornado that storm produced.  We did witness a large funnel that was ¾ of the way to the ground (may have touched down) near Gibbon, NE when the storm was not even tornado warned but had a nice couplet on radar.  You can see this at the end of the video below.  It soon became too dark to see much so we traveled to Columbus, NE to have our steak dinner after a successful chase!  Overall, I thought this would be a bigger day for tornadoes in NE than what it ended up being.  It was clear to me that it was just not as unstable with slightly lower dewpoints this far north as what was taking place in KS and OK, although the low and deep layer wind shear seemed to be similar.

Storm on the dryline with well defined inflow tail into the base near Beaver City, NE.  Inflow was quite cool at this point.

A closer view of the terrific structure/shape of the inflow tail into the base of the storm near Beaver City, NE.

Funnel starting to form out of the mothership storm base near Oxford, NE.

Initial tornado touchdown near Oxford, NE at 5:17pm.

Tornado with debris cloud starting to increase in size.

Beautiful rope tornado near Oxford, NE at 5:18pm.

Zoomed out view of the tornado with nice backlighting.

More photos from this day can be found here:  http://www.flickr.com/photos/39991047@N02/sets/72157629838076197/

Outlooks:

Storm Reports:

  This turned out to be a fantastic day that many, including myself, were thinking would be more of a straight line wind and hail threat and not worth the bother to chase.  However, morning storms moved through central MN into WI by early afternoon and laid an outflow boundary right through central MN in the vicinity of Hwy 212.  SPC issued a Severe Thunderstorm Watch along this outflow boundary at 1:30pm CT, while a supercell developed across western SD and was crossing over the border into western MN.  The thinking was that more storms, along with this initial cell, would develop along the boundary.  Well, low and behold, the supercell evaporated into thin air, likely due to the presence of strong capping along the boundary into MN.

  The aforementioned watch box was soon cancelled, while additional development was forecast along and ahead of a cold front entering the eastern Dakotas into northwest MN later in the afternoon, and possibly along the remnant outflow boundary that was rapidly receding north towards the I-94 corridor.  The airmass ahead of the cold front and along the outflow was characterized by dewpoints in the 70’s, MLCAPE of 2500-4500 J/KG, and 45 kts of Effective Shear.  The one concern was the southwest surface winds that were developing, but considering the winds aloft were out of the northwest, there actually was favorable low level shear in place for supercells and low-end tornado threat.

  Our course took us from Hutchinson northward on Hwy 22 and then west on Hwy 55 at Eden Valley.  Storms began to develop along and ahead of the cold front to our northwest near the Fergus Falls area and were strengthening quickly upon moving east southeast, so we continued northwest towards the cells on Hwy 55.  A new Severe Thunderstorm Watch was issued at 5:35pm CT that included all of central MN.  As we approached Hwy 29 near Glenwood, we had to make a decision to keep going west on the storm near Elbow Lake, or continue north to the storm near Wadena.  We chose the storm near Wadena as it looked like it was better organized and had a higher echo top compared to the western storm and appeared to be in just as good of an environment.  Later we find out that the western storm produced a beautiful rope tornado near Collis, MN.

  Upon reaching the storm near Parkers Prairie, we went east of town on Cty Rd 46 and set up the tripod to film a developing all cloud.  This wall cloud looked very good for while with fairly rapid condensation, but you can see in the sped up video how the RFD comes around and the wall cloud occludes and eventually gusts out.  We continued to follow on Cty Rd 71 and then south on Cty Rd 16 towards Rose City.  Here the storm cycled with another wall cloud and came very close to producing a tornado.  This wall cloud eventually wrapped up and we continued to follow on Cty Rd 1 and then east on Cty Rd 36 towards Long Prairie.  Traveling south on Cty Rd 11 and east on Cty Rd 10, another tight wall cloud with rapid condensation formed with a strong RFD surge.  Yet another opportunity for the storm to produce a tornado but it failed to do so.  To the east of Gutches Grove on Cty Rd 10, I’m 75% sure we had an elephant trunk funnel that stuck around for only 10 seconds or so as the wall cloud was producing the most rapid condensation I had seen all day.  Thereafter, the storm became outflow dominant with a photogenic shelf cloud as we traveled down towards Sauk Centre and eventually towards Belgrade where we called it a day after experiencing winds near 50 mph from the gust front.

Here is video from the day:

Fast condensation into a developing wall cloud east of Parkers Prairie, MN on Highway 46.  This is the first wall cloud seen in the time lapse at the beginning of the video.

Wall cloud tightening up, I believe north of Rose City, MN on County Road 71.  Notice the clear slot cutting in on the left side!

Shortly after the picture above.  Condensating inflow tail into the wall cloud with nice bowl shape underneath.

Rapidly rotating and condensating wall cloud at this point near Gutches Grove, MN on Highway 11.

Another view of the wall cloud and associated inflow tail near Gutches Grove.

Had to really crank up the contrast here, but I am 75% sure that there is an elephant trunk funnel in the front center.  This was at the point of the fastest condensation into a wall cloud that I had seen all day, and the area became tight, defined, and was rapidly rotating for about 10 seconds.  This was southwest of Long Prairie on County Road 10.  Video captured this much better.

Storm gusting out with a shelf cloud forming near Grey Eagle, MN.

Turbulent undulations on the cloud base in Sauk Centre, MN.

More photos from this day can be found here:  http://www.flickr.com/photos/39991047@N02/sets/72157627327597494/

Base Reflectivity of cell near the time it had a rotating wall cloud and looked the best near Gutches Grove, MN.

Storm Relative Velocity of the storm, indicating at least some rotation, when a rotating wall cloud was witnessed near Gutches Grove, MN.

Storm Reports:

Really was not sure if I was going to be chasing this day as I had worked the overnight shift the night before and did not have a chase partner, so this ended up being a spur of the moment chase. However, I convinced my wife, MaryLynn to take off work by later in the morning and we left Burnsville around 10:30am, targeting central SD near Selby. SPC had issued a 10% hatched tornado risk for portions of the central and eastern Dakotas within a Slight Risk for severe weather. An upper trough was giving a glancing blow to the area from the north, while decent upper level support was in place, along with impressive summer-time low level and bulk shear, along with moderate instability forecast to be 2-3k J/KG of SB Cape. I was particularly impressed with the forecast triple point and warm front to the east that storms were supposed to be moving along with the forecast storm motion, while a dryline moved south of the low. Forecast hodographs and soundings looking pretty good leading up to this day.

We traveled west on Hwy 12 through SD and all the way to Ipswich where we had to go south on Hwy 45 and west on Hwy 20 due to the road being closed near Roscoe as water had washed out the roadway around a week before. This was a re-occurring problem that we noticed through the day with damaged roads and some that were impassable due to water over the roadway. There is incredible flooding across central and eastern SD this year. We gassed up in Hoven (which later had a brief tornado occur near town), and traveled south to near Gettysburg, SD where we watched a developing supercell just to the south of the triple point. This cell did look good for a while and had a couple of cell mergers with weak, ragged wall clouds wrapping up and condensing after both mergers. But this cell could never really get its act together and weakened. We were near Faulkton when I decided to bail on this cell and travel northeast towards the cell near Hoven. Not more than 5 minutes into our drive towards this cell did it become tornado warned and then produced a tornado a short time later near Hoven. We approached from the south and thought we could see a funnel as we looked northwest near the Cty Rd 3 and Hwy 20 intersection. We followed to the east and up to Ipswich again and watched a beautiful shelf cloud on the leading edge as the storm approached Aberdeen, SD. There was a ton of rotation on the leading edge with this shelf and it became very picturesque. Upon reaching Aberdeen, we went to the northeast of town and got caught on a road that was impassable due to water. We turned around and got south in time to see a funnel near Groton, but never got any footage of it due to going in and of cornfields as we drove south. Thereafter, I got took some lightning video near Bristol and then traveled home through MN in a deluge of heavy thunderstorms.

I really thought there would be more tornadoes on this day, and this could have been due to a number of factors such as too much forcing in this time of year with impressive CAPE nearly each day, storms traveling more east-southeast into the warm sector and not directly interacting with the warm front (although one of these did and produced a tornado in northeast SD), or the fact that the surface winds actually seemed to die off some after initiation for some reason. Even though we did not see a tornado, I cannot complain too much as it ended up being an enjoyable chase day!

Here are a couple videos from the day:

First severe t-storm warned cell of the day near Gettysburg, SD.  Hail/rain core in the  middle and lowering starting to form to the left of the core.

Base starting to become lower and try to form a wall cloud on the supercell near Seneca, SD.

Ragged base of storm during a cell merger.  Appeared to be trying to wrap up after this but never could get its act together.

Heading northwest near Seneca, SD towards a beautifully structured, tornado warned supercell

Tornado warned storm starting to develop a shelf cloud as the outflow boundary gusts out ahead.

Awesome looking shelf cloud and turbulent underbelly west of Aberdeen, SD.

Another view of the shelf cloud as some impressive “sharks teeth” form on the leading edge.  Lots of rotation right on the leading edge of this shelf cloud as it approached Aberdeen!

Incredible lit up base as the sun was setting to our back.  This was shortly after the storm had produced a funnel near Groton, SD.

More photos from the day can be found here:  http://www.flickr.com/photos/39991047@N02/sets/72157627305833176/

Storm Reports:

Computer models had slowed down the progression of a system that was expected to originally blast through MN the night of 6/30, but the days leading up to 7/1 led to increasing confidence that a severe weather event was going to take place.  Temperatures across MN both on 6/30 and 7/1 had risen into the 90’s with portions of MN into the mid and upper 90’s (MSP hitting 99 on 7/1) ahead of a strong cold front that was expected to ignite severe weather across the state.  Dewpoints soared well into the low and mid 70’s as well.  Directional wind shear was less than adequate with primarily unidirectional winds forecast through the lower levels, although very strong deep layer shear was in place for supercells.  The main player in the development of intense severe storms was extremely high instability as MLCAPE values exceeded 4000 j/kg and a corridor of 5000+ j/kg nosed ahead of the cold front in MN that was being driven eastward by a very compact and strong 500 mb vorticity max.  Even though strong capping was in place, the intense forcing ahead of this vorticity center was enough to overcome the cap and sustain intense thunderstorms through eastern SD into MN and northern WI where widespread damaging wind and hail took place.

After getting off work, MaryLynn and I headed west on Hwy 19 to Hwy 169 south.  A very large, beastly supercell had developed in southeast SD and was heading northeast towards our location and the plan was to intercept this cell in the vicinity of Tracy, MN.  As we headed west on Hwy 14 towards Tracy, I realized the storm was heading northeast much too fast and we needed to get north and ahead of this storm ASAP.  We ended up heading north of Springfield, MN on Cty Rd 4 and crossed the MN River near Franklin to get ahead of the beast that was rapidly approaching Redwood Falls.  We traveled north on Hwy 5 and then east on Cty Rd 4 where I videoed the storm as it encroached on us from the west.  We could barely keep up with the storm, even traveling 60-70 mph!  To the southwest of Hector, I believe we witnessed a gustnado as a large and relatively tight debris cloud formed as well as a condensation funnel overhead.  Pictures of this are below, but not completely sure it was a gustnado or intense outflow winds and some sort of “finger” ahead of the developing shelf.  Thereafter, the storm produced intense winds as it overcame us and we saw many large tree branches down further east towards the Stewart area.

Instead of calling off the chase at this point, there were more storms developing to the southwest that would be at our location in an hour, so we stopped in Winthrop at the Eagle’s Landing Bar & Grill and had dinner.  Timing was perfect as we got done with dinner and went east of town where I set up the tripod and video camera and waited for the storm to approach.  This one had a beautiful shelf cloud and I managed to get about 15 minutes of really good video from this storm, as seen below.  After the wall cloud moved over and we got cored, the chase was over as we could not get back out ahead of the shelf at that point as it rolled towards the Twin Cities metro.

Shelf Cloud Near Winthrop, MN Video:

Intense HP Supercell Near Hector, MN Video:

Intense HP (high precipitation) supercell with shelf cloud north of Franklin, MN.

HP supercell catching us even though we are driving 60-70 mph to the east.  Storm gusting out a lot at this point.

What I believe to be a gustnado at the leading edge of the outflow  south of Hector, MN.  Notice the strong debris cloud with tighter “finger” funnel overhead.  Not sure if this is indeed a gustnado, but it sure appeared like one from what I know.  The debris cloud kicked up extremely fast and that is how I first noticed.

View shortly after the picture above of what I think was a gustnado at the leading edge of the shelf cloud.

Tons of dirt being kicked up due to the intense outflow winds from this storm.

Shelf cloud approaching us as we waited east of Winthrop, MN.

Really neat photo of a train passing ahead of the shelf cloud that was rapidly approaching our location.

Incredible shelf cloud!

Another view of the awesome shelf.

More photos from this day can be found here:  http://www.flickr.com/photos/39991047@N02/sets/72157626977879903/

Our relative position compared to the intense supercell northeast of Redwood Falls.

Our relative position where we viewed the shelf cloud east of Winthrop, MN.

Storm Reports: 

MaryLynn and I left Burnsville, MN around 12:30pm and headed down Hwy 52 as showers were approaching from the south.  These showers were developing on a northward lifting occluded front and a triple point lifting north along the MS River, while the warm front was further east into WI.  The area along these boundaries was in an environment of high speed shear and some decent turning in the low levels, while instability had increased due to a few hours of heating during the late morning as rain had moved north of the area.  This was all taking place as a deep surface low slowly meandered across southwest MN.

The showers became heavier and more pronounced as we approached Cannon Falls, MN so we decided to wait and see what they would do.  One shower began to take off north of town and a crisp updraft was observed on the low topped shower with a lowering beginning to form.  We followed north on Hwy 52 just as the storm became tornado warned and the shower began to show signs of rotation on radar.  The lowering soon formed a wall cloud near Hampton as we progressed east of the storm on Hwy 50 and then paralleling the storm north on Co Rd 85 towards Vermillion.  The wall cloud weakened near Vermillion and re-formed north of town near Coates.  We traveled west on Hwy 62 and then north again on Hwy 52, getting back underneath the cell as the wall cloud began to grow and the rotation became more pronounced.  Near the Koch Refining Company on the east side of Rosemount is where the strongest rotation of the wall cloud was observed with rapid condensation into the base, strong inflow, coupled with RFD winds that appeared to be dragging the smoke and steam from the refinery back around and into the shower itself.  It was a really cool sight to see but at no time did I see a funnel, although I would not be surprised if there was a spin-up around this time as it was looking rather impressive.

Thereafter, we followed up Hwy 55 and South Robert Trail into Inver Grove Heights as the wall cloud became the largest it had been the entire time.  As we took Hwy 110 west to 35E north, the wall cloud held together upon moving through St Paul but became more ragged upon moving northwest of the city.  The shower continued off to the northwest and we were not able to follow due to the traffic congestion on Hwy 36 and a similar circumstance and crash on I-694 west.  This cell did end up producing an EF-0 tornado in Blaine and Coon Rapids.

The amazing thing with this cell was that there was not any lightning through the duration that we were following, likely due to being low-topped and not high enough above the freezing level to lead to a separation of charges and, therefore, lightning.  It was interesting to witness several wall clouds out of a small shower.

Here is the video:

Shower with sharp updraft and developing base near Cannon Falls, MN.

Base of the now tornado warned shower near Hampton, MN.

Wall cloud forming near Hampton, MN.

Wall cloud dissippating with rising motion into the base as we traveled on Hwy 50 east of Hampton.

Structure shot of shower and base over Vermillion, MN.  Notice inflow tail to the right wrapping into the cell.

Wall cloud becoming much tighter and more pronounced near Inver Grove Heights.

Large wall cloud with rotation moving north-northwest of Inver Grove Heights.

More photos from this day can be found here:  http://www.flickr.com/photos/39991047@N02/sets/72157627022778876/

Storm Reports:

After seeing 3 tornadoes the day before, MaryLynn and I left Tulsa, OK the morning of the 25^th and headed up I-44 towards the St. Louis area.  There was another High Risk in place for severe weather, this time across southeast MO, northeast AR, western TN, western KY, southern IL and southern IN, where a tornado outbreak was expected due to the extreme instability and wind shear.  The set-up included a strong upper low moving east from KS into MO through the day with a surface low into northern MO, a warm front draped east of the low through northeast MO and south-central IL and a strong cold front advancing through AR back into TX.  An intense shortwave and vort max was forecast to round the base of the trough and kick off the severe weather threat and tornado outbreak across the region, in an environment characterized by dewpoints in the upper 60’s and 70’s, over 70 kt mid level winds, 2500-3500 MLCAPE values, and extremely high helicity through much of the lower atmosphere.

The terrain through which much of the High Risk and greatest tornado threat was in, was a very hilly area characterized by winding roads and dangerous chasing conditions.  Our plan was to head towards the northern end of the greatest tornado threat and go for storms more along and just south of the warm front through northeast MO and south-central IL.  We first stopped in Waynesville, MO for lunch and were treated with the first tornado warned storm in the warm sector of the day.  This storm had several weak wall clouds on it as we followed up I-44 and even a horizontal funnel near Doolittle, MO.  Storms began to congeal near St James, MO and we ended up trying to get ahead and through St Louis, MO into IL before storms would reach us.  As we approached St Louis, a supercell rapidly developed ahead of the main line of storms and we witnessed a very low, sharp and rapidly rotating wall cloud enter the southern St Louis suburbs and actually drove through nickel sized hail on I-270.  This wall cloud was the closest thing all day to producing a tornado and could very well have as there was a tornado report out of the St Louis area near the time this storm was going through.  The pictures below detail just how close this storm came to producing a tornado right in the St Louis metro area.  It was a rather scary scenario and thank God the storm did not produce a large tornado as it moved through this heavily populated area.  Towards early evening, the storms got messy and the best looking supercells were well to the south of our location, so we got ahead of the advancing squall line and got cored by a line of storms producing damaging winds and small hail near Mattoon, IL.  Thereafter, we drove through the night and got back to Burnsville, MN very early the next morning.

Here is the video:

Driving by Joplin, MO along the Interstate, we noticed major damage, even though Joplin is a few miles north of the road.  Joplin took a direct hit by an EF-5 tornado on May 22nd, 2011 and was completely descimated.

More damage as seen along I-44 driving near Joplin, MO.  Makes we wonder if there was a satellite tornado or if it was indeed that massive.

Weak wall cloud approaching us in Waynesville, MO.

Horizontal funnel near Doolittle, MO.

Intense storm with decent structure and wall cloud as seen on the bottom left near Rolla, MO.

Intense supercell and very low wall cloud approaching Concord, MO, the southern suburb of St Louis.

Extremely tight wall cloud, possibly large funnel, that was rapidly rotating near Mehlville, MO in the southern St Louis metro.

Another view of the vault and wall cloud/funnel near Mehlville, MO in the southern St Louis metro.

Closer view of the wall cloud/funnel close to the ground near Lakeshire, MO.

Shelf cloud about to overtake us in Vandalia, IL.

More photos from this day can be found here:  http://www.flickr.com/photos/39991047@N02/sets/72157626755184785/

Storm Reports: