Thursday, September 30, 2010

2010 Storm Chase 48 Report - September 22nd - An Unfavorable Solution

With a deep trough aligned over the Great Basin and some great moisture return out across the high plains, what wasn't to like? Well, here's what I didn't like: The models just weren't consistent with painting the picture of how everything was going to play out. The short term models seemed to favor cyclogenesis along the Nebraska/Wyoming border, with it intensifying toward dark. However, they weren't extremely consistent with this. Still, I figured that with a areas of lift pulsing through the exit region, we would have a good chance of seeing a nice tornadic supercell. The tornado threat is also outlined with SPC's Convective Outlook for September 22nd.

Already that morning, severe storms were rolling across northern Nebraska, pounding areas with large hail. Interestingly, these storms began the night before along the Front Range which prompted me to be out shooting lightning. As I woke up, suuthwesterly winds scoured moisture out of the shadow of the Front Range in Colorado, but moisture was holding strong along the eastern border and into Kansas and Nebraska.

I headed out with Tony Laubach and Ed Grubb and we met Johnathan Skinner at the rest area in Wiggins and he joined us. Upper level support was already upon us and the well-heated plains already started to boil. We could see convection off to the southeast as we headed eastbound on I-76. We stopped at Julesburg and got to some higher ground south of town to observe and wait for the day to evolve. Tony spent most of the time enjoying the attention of a herd of cattle.

Mesoscale Discussion #1887 was issued at this time. We could see a boundary on radar that stretched across southwest Nebraska. This boundary at one time was a cold front that had pushed south across the plains and had spent the day prior rather stationary. With southerly flow and the trough approaching, it began to act as a warm front, though it was never anchored to a surface low. The airmass to the south of the boundary started to mix from west to east as the day progressed and we started to worry about ever seeing an easterly component to the southerly winds. Still, convergence along the boundary was breaking the cap and towers began to shoot toward the sky from Akron, Colorado to Gothenburg, Nebraska. The better moisture was obviously to the east, so the eastern storms were stronger. We continued past our original target of Ogallala and stopped in North Platte to refuel, waiting for the string of pearls to greet us along I-80.

The line of storms from North Platte.

As we were leaving North Platte, Tornado Watch #684 was issued. The difficult decision at this point came from the fact that none of the storms in the line seemed to be stronger than the others. A few pulsed up to a more intense strength but we couldn't seem to find one that took over. We tried to predict where the best inflow was and that brought us through some light cores with maybe half inch hail toward Gothenburg, where we tried to head south to get on the inflow side of the line.

We dove a bit south of town and the view wasn't much to speak of. I didn't even take any pictures. A cell back west started to load its core, so we decided to get back on 80 and get on it as opposed to going south and going around. We headed south at the Maxwell exit and attempted to core the storm, but the road turned to dirt after the the scenic Cottonwood Canyon reservoir and the storm seemed to pulse down as well. A cell in the line to the east now looked stronger, so we headed back to the Brady exit (between Maxwell and Gothenburg) and headed south for a few minutes before that storm pulsed down.

We soon found ourselves in the parking lot at a gas station near Brady, trying to figure out what to do. We had been looking at CAPE and the radar all day, but it dawned on me that it might behoove us to look at pressure since a lot of the surface winds at nearby stations were being affected by nearby storms. To our dismay, there was no real low on the Nebraska/Wyoming border. The lowest pressures were along the boundary, directly to our north, a little to the north of Stapleton... and it appeared to be slowly moving east. That would explain why the surface winds were due south all day and thanks to the fact that the upper level winds were southwesterly, there really wasn't that much wind shear and thus, we couldn't get anything severe to save our lives.

It was getting dark and I realized that if we were going to see something tornadic, it would have to be east of the low along the boundary which stretched from Stapleton through Broken Bow and further ESE from there. There wasn't a lot of optimism in the vehicle at this point and eventually, we decided to head east, hoping one of the cells near Gothenburg would get something going. As we were heading east on I-80, a cell along the boundary near Broken Bow became tornado- warned.

We were still at least an hour out if the storm was stationary, so that wasn't going to work. Still, there were a few cells heading that way and the hope was that they'd move north and hit the boundary and turn. We left the highway at Gothenburg and started to head east and eventually north, but it seemed like everything was turning to garbage fast. We stopped as our cell was an outflow mess and the cell to our north weakened. Even the once-tornado-warned cell had weakened. I tried to grab a lightning shot as we sat in the outflow, but to no avail. I even bared my chest to the storm in an effort to scare it into shape, but that didn't work either.

The obvious outflow mess.

And that, was that. We saddled up and headed on home. It's funny... on successful chase days, I can go forever without eating, but on days like this, I look to food for comfort. I found that comfort at Sonic in Sterling. It was, as they say, Sonicgood. The four of us had a lot of energy built up from the day, so we got a little goofy...

He's snatchin' yo' people up.

I don't like to have to beg to keep a fella' out of the trash, but I made an exception.

We even timelapsed the moon. Perhaps I should look at that footage... hmm... By the way, the gas station near the highway exit in Sterling has ridiculously high prices. It was over three dollars a gallon for regular, while down the street it was $2.70. Lame.

Mileage: 728
(Year-To-Date): 17652 (incidentally, this chase put me over 50,000 all-time chase miles)
Largest Hail: 0.5"
Winds Of Consequence: None observed.
Tornadoes: 0

Other reports on the date:
(None) ... apparently no one wanted to talk about it.

Official storm reports from September 22nd.

Detail map:

It was fun to head out with some good friends, but the weather didn't cooperate. Due to the orientation of the boundary and lack of a strong surface cyclone (even perhaps more so the weak cyclone along the boundary too far to the east), the surface winds never really aligned themselves in a manner that would support a decent supercell. In retrospect, I think there may have been a hint of this in the models, but the inconsistency definitely lead us to focus on the more favorable solutions.


Wednesday, September 29, 2010

2010 Storm Chase 47 Report - September 21st - Greenwood Village, Colorado Lightning

I had watched as moisture slowly increased throughout the day and knew we'd have a little upper level energy coming through again in the evening. Still, I settled down for a movie. I got a couple texts about some lightning on the north side of the city as the sun was going down, but finished my movie.

Afterward, I noticed that new storms were still popping up over the same area. I don't remember the actual synoptics of the day, but I suspect there was a bit of a jet streak over the area. I had to run to the market anyway to get a few supplies for a planned chase the next day, so I brought my camera along.

There was enough activity on the north side of the city when I got out that I figured I'd go sit up on my lightning perch and see what I could see. Luckily, a new cell popped up and started spitting out a bunch of lightning, so I rolled all the windows down on Der Schploder and cranked ... And You Will Know Us By The Trail Of Dead's "Century Of Self" on the stereo, which is an excellent record by the way, pulled out my tripod and a bag of Starbursts and enjoyed the show.

This event was not without frustration however. I ended up having some camera problems which I still haven't completely figured out, but I've troubleshot it to the point that I know if my viewscreen is turned off, the camera gets kicked out of manual focus. This has never happened before, but for whatever reason, that's what it's doing. After a few in focus shots, I got two great shots (pics 2 and 3) below that were horrifically out of focus. After the first bad one, I reset the focus to infinity and turned the screen off (to save battery power) and my very next shot (pic 3) was the same. At first, with both shots, I was so excited to get great bolts in shot, but then shortly thereafter, I found myself devastated.

Not even sure why I bothered with the watermarks on these two... sigh.

I took about twenty more shots and ended up only capturing this:

However, with the battery light blinking on my camera and fatigue and frustration setting in, I decided to pack it in... but not before one last shot...

So I got to take one winner home with me. :)

Mileage: 6
(Year-To-Date): 16924


Monday, September 27, 2010

2010 Storm Chase 46 Report - September 20th - Greenwood Village, Colorado Lightning

Saw a wave coming out of the mountains, so I went and gargoyled for a little while at my favorite perch. The best lightning was to the north, early, but I didn't get any good frames. As the line passed, there was a little strengthening just to my south which increased the amount of intracloud activity, so I was able to capture a few sparks.

Mileage: 3
(Year-To-Date): 16918

Sunday, September 26, 2010

2010 Storm Chase 45 Report - September 14th - Incredible NW Kansas Supercell, Sherman & Thomas County Tornadoes

I was corresponding with Eric Treece on the morning of the 14th. Being that he had decided not to chase the severe weather event in northern Kansas and southeast Nebraska on the 13th and the fact that he would soon be returning to work, he was looking for an excuse to get out for a chase. I hadn't really looked at anything yet, so I decided to look things over and get back to him.

A weak trough sat along the west coast with a deep(er) upper level low out in the Gulf of Alaska. A weak 500mb ridge was situated across the center of the plains. The day prior, as the trough approached, southerly flow began again on the plains and pushed a stationary boundary which was stretched across Kansas further north into Nebraska and points northward. Colorado spent the day mostly in downslope, mixing out a lot of moisture in the air. Early in the morning, a weak shortwave came through and fired some elevated storms in northeast Colorado which persisted and moved NE across the Sand Hills.

That morning, dewpoints in Colorado were between the upper 20s and low 50s (in the far NE corner of the state). 60ºF dewpoints existed across the border in Nebraska and Kansas.

Looking at the models, it appeared that the moisture would increase throughout the day and while lee cyclogenesis was not expected, troughing was certainly present. Though there appeared to be just enough moisture convergence at the surface along the eastern border of the state, I did see a bit of upper level support moving through at 0Z on the 500mb vertical velocity charts. Though the cap looked strong (on both the NAM and GFS) in Kansas and Nebraska, there was enough CAPE west of that for me to be happy with our chances. At least, I figured, we could score a nice isolated supercell like the week prior in the Nebraska Panhandle. Plus, the hodos looked great if we could get something to fire. I called Eric back and told him if he didn't mind a ward, I'd be in for going.

SPC's Convective Outlook for September 14th

I made my preparations and drove out to his place in Elizabeth and we were on our way east. Our preliminary target was Wray/Idalia, CO, so we hit CO 86 and then continued on I-70. Along for the ride was Eric's basset hound Fred, who is pretty awesome, by the way.

As we headed east, I saw one thing that worried me and one thing that looked promising. The worry came from the dewpoints in eastern Colorado and northwest Kansas beginning to mix down. However, even in the dry environment over the Palmer Divide, showers were forming. Considering that there was little if any mixed layer CAPE showing up on mesoanalysis, I figured we had a bit of upper level support moving through. I figured at least we'd have some storms then... but I wished we weren't sitting in 90/48 air. McCook, Nebraska still had a dewpoint in the 60s, so I thought maybe going further north might behoove us. We ended up heading to Wray, which was our target anyway, by the time a line of high-based thundershowers was within a county or so. Even though reflectivities were low, there was a decent amount of lightning showing up, which I figured was a good sign. We drove a bit east of Wray and then south on dirt and just kind of watched the sky for a while, making sure to pick the burrs out of poor Fred's paws. Poor fella'.

We sat a few miles south of Eckley for a good while, watching the thundershowers approach from the west. They were rather disorganized (or at least the radar presentation was) and there was an awful lot of anvil cloud which soon cast a shadow over us. I didn't like the fact that there was shadow now dampening the heating on air that had already mixed out a lot of moisture. We were struggling to keep a 50ºF Td at our location, though it was much more moist and cool to our northeast. The strongest cell in the line was on the southern end, in the driest air, no less.

Eric checking data; Fred exploring.

High-based storms approaching.

Portrait of Eric & Fred.

At 2243Z, Mesoscale Discussion #1828 was issued, including our location and points northeastward. It basically discussed the "jetlet" moving through the area and the propensity for storms to continue, especially in Nebraska late. It even mentioned the T word. That was a bit of a boost of confidence, so we now had to decide whether to go north or to stay south with our line. I liked the environment to our northeast but the cloudcover worried me. Plus, it was hard to ignore the line moving at us, especially the southern cell which was beginning to strengthen to my surprise (even in the 35-45ºF Td air). It really was too hard to ignore, so I made the recommendation to head south and we did just that, on a nice, broad dirt road known as County Road U.

From what we could see, everything looked messy to the southwest. We couldn't see the base of the southern storm, but the precipitation looked scattered and diffuse. Looking at the radar presentation, this was a bit confusing. I mean, it *looked* supercellular on radar. Surely it was just a trick.

Click for larger image. Our location shown in in pink.

Finally, just a few miles north of US 36, we found ourselves looking at a beautiful high-based supercell. The radar wasn't lying to us! It had a big, flat meso on it and no visible wall cloud. On the southern flank of the meso, a lot of dust was getting kicked up, though we were still in info. A tornado watch, #660 was issued, but to our disappointment, it was far to the north. We were still happy, though. I think both of us were a little pessimistic about the day and here we were staring down the barrel of a beautiful Colorado supercell.

Scud getting kicked up by the rear-flank outflow.

View to the north.

Wider shot of the big, flat meso and the golden light pouring through from behind.

At this point, we noticed that some strong convection was forming to our southeast, probably near Sharon Springs-Cheyenne Wells. It wasn't showing up on radar yet, but looked very strong.

We readjusted south and east as the storm approached. The outflow on the rear-flank was quite strong and was kicking up a lot of dust, but a narrow inflow notch existed wherein scud continued to rise to the base.

Fred was quite interested in knowing where Eric was at *all* times. :)

Brief wall cloud that formed at the base before precipitation wrapped, seeming to cut it off for a while.

Tumbleweeds getting lofted along the rear-flank gust front, wall cloud dissipating.

Surface obs at 0043Z showing moisture on the increase again with strong southeasterly winds ahead of the storm.

Around this time, Severe Thunderstorm Watch #661 was issued for our area. We briefly were outrun by the outflow and subsequent dust storm before hitting pavement on US 36 and getting back ahead of it. Fat drops were occasionally falling out of the anvil and the cloud-to-ground lightning, even far away from the main cores was very impressive. By now, the cell to our southeast had strengthened and was showing returns on radar. It was moving due north ahead of our storm, which was heading due east, its storm motion, perhaps influenced by the low-level jet kicking in. As we got to US 385, intent on staying ahead of it, we stopped for another photo op. The structure, though I've perhaps seen similar, was nothing short of amazing. There was the flat meso which stretched southward, a tiny wall cloud and what looked like two horns stretching up, coreward. It looked like a bull.

Meso and wall cloud dwarfing Idalia, Colorado.

"The Bull"

At this point, the storm lost its wall cloud and seemed to become outflow dominant. Several more small cells appeared in its path as well as the larger storm which had just crossed I-70 and was screaming northward. The cloud-to-ground lightning was incredible and seemed to be everywhere around us, though we were only seeing a few fat drops from time to time.

Lately, I fell as if I have lost some of my fear of lightning, which I know is not good! However, as we sat on higher ground near a radio tower close to the KS/CO border on US36, my fear of lightning returned! No part of me wanted out of that protection of that rolling Faraday Cage.

I figured our storm was going to be rolling into turned over air from the cells in front of it and also into the highly capped air in Kansas, so I didn't give it much faith. At this point, our mission turned toward lightning. We desired to stay out in front of the storm, so we headed to Saint Francis and found some higher ground northwest of town for some lightning shots. Though our original storm was warned for high winds (not surprising considering the outflow we saw), we set up for lightning.

The red glow from the setting sun made for a cool picture. Actually, given the earlier bull reference, it reminded me a bit of the Last Unicorn. (Think the red color in the waves before the Red Bull emerges).

Since everything was getting messy up north and the original storm was still heading east, in fact, now diving a bit to the south, we decided we better head south. Even in the wake of the northward moving storm, which was just about upon us in Saint Francis, the warned storm maintained strength. We decided to punch south on KS 27 through the northward moving cell to get out ahead of our original cell.

As we punched the core of the northward moving cell, it appeared to exhibit a bit of rotation on radar. In fact, so did our original cell. I couldn't wait to see what things looked like when we made it through, though it was dark. We encountered only small hail and heavy rain as we passed through, and I could see a nice meso to my west, belonging to the northward moving cell. It was then that I looked southwest and saw that the original cell had a nice lowering on it. I struggled to get my video camera out to try and record it and unfortunately, the first video I took did not have the correct settings, so it turned out very dark. I was able to pull this screen capture, though which corresponds to about 0159Z:

I'm not sure that I am able to eloquently communicate how I was feeling when we gained visibility and saw one mesocyclone to our west and another HUGE mesocyclone with a distinct lowering to our southwest. My eyes got as big as dinner plates and luckily, I changed my settings and was able to get some decent night-time video. We stopped south of the county line in Sherman County and got out. I couldn't decide what to take pictures of!

Meso on the northern storm.

Lowering on the storm to the southwest. The wall cloud looked to lower and almost contact the ground before the rain from the forward flank obscurred it (and probably added to the lowering as scud was being drawn up from it).

Wall cloud begins to develop on the northern storm.

Another shot of the northern cell with a nice cloud-to-ground strike.

Back to the southwestern storm, rain has wrapped completely around the lowering.

At this time, a tornado warning was issued for the storm as NWS employees had spotted a cone tornado, which we didn't ever see, though it looked close several times. Facebook friends can watch a video taken from 0200Z to 0210Z here: VIDEO. In the video, you can see the incredible structure of the southwestern storm and the shadow of the meso of the northern storm. I thought that was amazing! I do have another *dark* video from 0158Z to 0159Z which shows a lowering VERY close to the ground (as seen in the screen cap above). Here is what the radar looked like at about this time. Our position, again, is in pink.

We knew we were going to have trouble keeping ahead of it unless we made haste, especially since it was really right moving into the low-level flow. We blasted south to Goodland and negotiated some brief road construction before getting on I-70 and getting ahead of the storm. I tried to keep tabs on it through the rear-view, but didn't have a good bead on any lowerings as it was night and hard to maintain a good watch. We stopped in Brewster for another look and had made decent progress on keeping ahead of it. The notch was less apparent at this time and it almost looked linear; shelfy. However, we did see a brief wall cloud form in a little kink and then quickly fall apart. We reported it since we had a moment, but resolved to keep ahead of the storm. Here are a few pictures from Brewster:

The inflow was really screaming into the storm and I was surprised that it hadn't become completely elevated. I guess the low level flow was warm enough to keep from decoupling.

The storm was really making a hard right turn at this point, so we dropped south out of Brewster and began to stair step our way south and east ahead of the storm. I can say that it had some of the most incredible structure I have ever seen and as it evolved, became this huge mothership mesocyclone, if you will. It just seemed to fill our windows and vision at all times as we kept pace.

The moon, hiding behind the southern edge of the meso.

We stopped for pictures again 7 miles east of Brownville and had time to set up tripods. In retrospect, I wish that I had put the video camera out, but I was able to get some decent stills. We watched a lowering for a while and for a minute or two, it appeared (convincingly) as a nice cone tornado. As it lifted, there was a distinct staccato lightning bolt right in its vicinity. This was the only time in this stage of the storm that I witnessed lightning like this. There were a few normal cloud-to-ground strikes and and insane intracloud lightning, but this was a very brief and extremely bright strobe. There was also some fairly strong rotation on radar here. We did call it in while it was down but stopped short of calling it a definitive tornado. (In retrospect, it's convincing to me)

This photo shows convincing evidence of a fully condensed tornado at 0334Z.

Tornado lifted a minute or so later.

Staccato bolt.

Reflectivity at the time, our position in pink.

Base velocity at the time, our position in black.

We continued on to the east side of Monument, KS where we set up shop once again. I noticed that a light of some sort seemed to hover off to the east of, but very close to the meso. It wasn't until we stopped that I convinced myself that it was an airplane. In fact, we saw two such planes seeming to fly very close to the meso. It's hard to say what they were doing, perhaps looking for a way around. I believe Eric has a picture of one of them.

Anyway, the scene at Monument was monume-... amazing... incredible. Eric chose a good place to stop with the town in the foreground... it really set the meso off. The lightning was incredible as well and the thunder never stopped. We sat there in the 25kt inflow for a twenty minutes or so enjoying this incredible storm. Even Fred seemed to be enjoying it. To top things off, a very bright moon lit up the southern edge of the meso, setting it off even more. It is definitely worth checking out Eric's wide angled shots of the meso at the link to his report below. He got some incredible imagery.

Lightning, seeming to stair-step down the outside of the meso.

Monument, about to get devoured.

The extent of this incredible mesocyclone.

I'm still not sure why, but at this point we just decided to pack it up and head home. Dare I say we were satisfied? It was getting late... but really, I think we were just very happy with what we had seen. Part of me wonders why we didn't just keep going as the storm carried a tornado warning for an additional two hours, if I'm not mistaken. Whatever the reason, we briefly endured some rain near Monument but then went to Oakley and got on I-70 for our trip home. To say that we were high on this incredible storm would be an understatement.

We arrived back at Eric's place between 7-8Z and I was back home before 9Z. My head was buzzing as I briefly looked through my photos before heading to bed. The lightning stair-stepping on the outside of the meso about made me cry. Seriously, that is probably one of the best captures I've ever made.

Finally, I'd like to give a shout-out to the HRRR. On a day that I had low confidence the HRRR seemed to see something like this coming. Like I stated in a previous post, I don't rely on the precipiation models for an exact geographical presentation of where to chase, I like to look at the predicted storm type (via reflectivity) and distribution. The model generated an isolated "supercell" and right-moved it into NW Kansas. Not too bad, eh?

Actual radar loop. Note the northbound supercell in front of the monster coming out of Colorado!

Mileage: 654
(Year-To-Date): 16915
Largest Hail: 0.5"+
Winds Of Consequence: 50kt+ (estimated)
Tornadoes: 1+ [4NE Brownville (or 10SSE Brewster) and one or two close calls northwest of Goodland.]

Other reports on the date:
Eric Treece (VIDEO)
Goodland NWS Recap

Official storm reports for September 14th.

Detail map:

Finally, I know this sounds selfish, but one of the most satisfying aspects of this storm was that for the most part, no one else was on this storm. There was a young fella' Nebraska that wasn't too far off, but it was our storm. With the proliferation of storm chasing over the past few years, it is not often that you get to experience a nice storm like this without tripping over someone else. I think we saw only one local out spotting as well.

Between this incredible supercell and that beautiful LP in the Nebraska Panhandle the week before, September 2010 will be a month to remember. Thanks again to Eric for letting me come along.