Thursday, July 30, 2009

2009 Storm Chase 33 Report - July 28th - Thundermist

Okay, you know how this starts: "I wasn't going to go out ..."

I had watched a few showers roll off the Footies and die over the course of the evening. I had been looking at the RUC forecast soundings for the area, though, and noticed that we had a good deal of CAPE along the foothills and the Palmer Divide and that the cap was forecast to weaken a bit, though the local weather service had written off the chance of storms for the remainder of the evening.

Another round of storms popped up over Rocky Mountain National Park and started to turn to the southeast. As they emerged from the mountains, I activated the lightning net and received word from folks on the north side that the storms (there were three distinct cells) were not producing much lightning.

The third storm in line was the strongest and the hail algorithm was predicting 1"+ hail. I paid close attention to the VIL and Echo Tops to see if the storm was strengthening. It appeared to be low-topped to some extent but noticed that as it came off the foothills, the tops went up and it almost seemed to have a little hook on it. At that point, I hit the road.

I watched the radar as I headed north on I-225 and saw the storm began to intensify. I merged onto Peña Blvd after getting to I-70 and headed north, now very close to the storm. The lightning was frequent but more flashy than anything. The main precip echo was almost to my north at this point, but to my northwest, I saw a large area of cloud structure sticking out of the bottom of the updraft right over the Rocky Mountain Arsenal. It was hard to see as I was driving and there wasn't much if any lightning behind it, but it looked like a wall cloud.

I increased speed to get to my perch (of sorts) at Tower Road and Peña. I parked and quickly got my equipment out. I noted rotation in the cloud structure and started taking some pictures.

I called Tony Laubach as it approached to see if he could see any rotation on radar. He could not. While talking with him, the structure faded and a new one formed more to my north. I quickly noticed that this one was moving anticyclonically. Literally two "blocks" to my north, though the storm was moving to the southeast, I watched RAPID right-to-left motion which was moving directly toward me. I tried to take a couple pictures but it was soon on me with strong wind and HEAVY DRIZZLE. It was very odd.

The cloud structure was moving rapidly from the right to the left of the image and then wrapping back behind the storm.

I drove south on Tower Road and got out of the precipitation. When I got to I-70, I decided to head east and keep up with it. I realized that though I had gone out for lightning, I hadn't been taking pictures of it! In fact, I recalled a couple cloud to grounds off to my northeast at my previous spot. As the storm passed over the radar site, I lost sense of its structure, but I could see some interesting structure in front of me. It looked like a shelf cloud (on side view). The CG's out ahead of it were stunning. These were some very INTENSE discharges. In fact, one repeater (as I call them ... a CG with more than just a few return strokes) hit something ... so that when the actual bolt was gone, it looked like lightning was flashing off the ground for a good while.

Finally getting a good look at the storm, it appeared to be continuing to strengthen. I really wanted some lightning, so before getting into the core, I stopped at Airpark Road and set up. Unfortunately, the heavy drizzle arrived again and made shooting difficult. I packed up again and drove through the remnants of the core, encountering a bit of hail on the highway. I stopped at Manila Road and found pea-sized hail and some minor flooding there before continuing on to Bennett.

From Bennett, I continued to shoot lightning as the storm rumbled off to the southeast. I did manage to capture a few shots worth sharing:

When I got home and was able to look at the radar loop, I figured out what was going on with the storm. Sitting under northwest flow, the mid level winds were pushing all the precipitation into the direction of storm motion. The surface winds were 180º from storm motion and I believe that while there was enough shear to get the storms spinning, a rear-flank (of sorts) downdraft would continually punch through the updraft as the storm cycled, separating the rotating portion of the updraft and leaving it behind. This is what I saw from my first intercept and this also appeared to happen on radar as well. Eventually, the RFD punched more to the posterior side of the storm and the rotation picked up again. I was actually very surprised that the storm was not tornado-warned after it crossed I-70. It had a nice couplet on it for over a half hour (at the lowest scans). In fact, both KFTG and TDEN were indicating TVS after TVS in the couplet.

It literally boggles my mind why this storm was not tornado-warned. Maybe the folks up there in Boulder were taking a nap or something. It was rather late at night and they dropped the thunderstorm forecast. (Crazy too, because this wasn't the only storm ... clearly, a short wave was coming through).

Anyway, I've included a few radar images below.

The storm at the time of my first intercept near DIA

The storm as it crosses I-70 (notice the hook).

An obvious area of rotation.

Just one of the many scans from TDEN that carried the TVS

So, to recap ... a very nice surprise. Got a few lightning shots, got a few structure shots ... and the only other chaser out (as far as I know) was Jon Merage. Though I had to call it a night early (work early the next morning and insufficient funds), it was still another great chase for this amazing year.

Chase Map:

Mileage: 82



KPUX from July 29th as big hailer supercells erupt all over southeast Colorado. I don't even want to talk about the tornado machine that came to life south of Limon. I'm going to close the book on that one.

Monday, July 27, 2009

Storm Spotting - July 27th - Denver-Area Storm

So ...

... we had some storms in Denver today! I was pretty caught up at work to pay much attention until I saw it get rather dark outside. When I poked my head out, I saw this: (taken with my phone)

I didn't have my camera with me at work, so I just sat outside and watched a weak wall cloud lower and then cycle. The RFD cut the updraft in half and pushed the rotating areas south and out of contact with the main storm. We watched this happen a couple of times. Soon, the 30-35kt winds blasted us with rain and we stayed inside ...

After I had sat home for a while arm-chairing while other chasers caught up to the tornado-warned storm near Limon, I watched a wave come down the Front Range ... you could see it lighting storms on the footies and I knew it would intensify as it hit the metro area. ... and it did. I saved a radar image but for whatever reason, it didn't turn out. Anyway, I grabbed my tripod and headed over to the field near my house. The south end of the storm (which was moving SE) seemed to pulse and shelf out.

It was still rather light enough, but there was enough lightning to warrant trying some lightning shots. I set the camera to F8 and started taking some 0.6" exposures. Though I didn't know it at the time, I did capture some lightning in this image:

As the storm approached to my WNW, I watched a smaller cell put down a ton of cloud-to-grounds to my south-southwest, so I aimed there and kept my finger on the shutter, hoping to time one of the repeater bolts and get one of the return strokes. ... and it turned out, that I managed to grab two within a minute or two of each other! I'm not going to lie ... I was proud of myself.

With that, I headed back in, not wanting to get my camera equipment wet. Unfortunately, as I sat and watched the storm come by and weaken on radar, I left my damn window open again, inviting in the rain to dampen my carpet. I'll learn eventually!

When the storm passed, I thought I'd try and go back out to get some more lightning. It had weakened significantly, however, and I just managed to get a nice shot of some of the nearby buildings with the late evening light kissing the bottoms of the retreating cloud deck.


Saturday, July 25, 2009

2009 Storm Chase 32 Report - July 25th - Saturday Night Thunder

So, as the story goes: I didn't plan on chasing storms today. In fact, I mused earlier about how hot the 700mb temperatures were. Surely, nothing would make it off the mountains. However, a few cells managed to pop up in the Metro, though none of them went severe.

At about 6:30PM, I walked over to the mail center at my apartment complex and noticed some VERY stout convection just to my east. When I got back to my apartment, I looked at the radar ... nothing ... I looked at Cheyenne and Pueblo's radars (they cut through the air at a higher level over Denver and can often show storms before the local radar does) ... nothing. I peeked back outside and saw a lowering to my southeast on the updraft.


Well ... I had planned on heading to the market to pick up dinner, so I figured I'd bring my camera with me. Finally, as I left, something started popping up on radar. I got on Arapahoe Road and just continued driving east until it was raining ... and raining rather hard! By the time I reached Arapahoe and E-470, there was a lot of water on the road. I called a friend working at UDFCD to alert them (they do flood control) and continued east. I wasn't sure what my goal was at that point, but I continued east until I got out of the rain and watched the cell begin to die on radar.

To my south, another cell on the Palmer began to surge northward, so I continued east on County Line Road to the Kiowa-Bennett Road where I worked my way south. A shelf cloud began to materialize on the shelf and this excited me. I had a paved road and a nice shelf ... what more could I ask for?

When the shelf came over, I found myself in the whale's mouth. My photos didn't come out too well do to the low light and not setting up my tripod because of the precip. The wind was less exciting than I expected, so I eventually continued south toward Kiowa. Most of the storms around began to weaken, but there was some interesting turbulence in the clouds.

I got on Colorado 86 in Kiowa and started to head home. I noticed that cells were beginning to strengthen over Denver so I hurried a little. I could see some interesting cloud formations to my north, so I turned north just before Elizabeth and tried to get a better look. Eventually, I had a view of the "interesting" feature, which could have "appeared" as a wall cloud. However, there wasn't much on radar there, so it was probably just scudzilla.

I continued north to get a good view of the cells coming out of the south side of the Metro and as it got dark, found a place to set up and shoot lightning. I was there for a while and managed to score one shot, which I'm happy with.

It began to precipitate and I figured I was done for, so I started making my way back home again. A bit later, I found myself thinking it would be cool to get the night sky with an oil pump in the foreground. So, I stopped. The rain was light and I took a ton of shots ... barely missing a couple of lightning bolts. But, I was so pleased with how they came out, the lightning would have only been a bonus.

Eventually, the lightning came to a halt and I knew it was time to go home. I had originally thought to pick up a steak from the market but I didn't want to curse myself by eating steak after a "chase" without a tornado intercept, so I stopped at Sonic instead. That turned out to be a very, very good idea.

Mileage: 90
Features: Shelf cloud, minor street flooding
Hail: None
Wind: Sub-severe.


Tuesday, July 21, 2009

2009 Storm Chase XXXI Report - July 20th - Crazy Severe Weather In Denver!

I got home from work at about 6:30PM yesterday (Monday the 20th) and turned on the radar only to see this beautiful creature rolling through Goodland:

After going through the usual "If I left now ..." calculations, I realized it was hopeless. Even worse, none of my Colorado chasing buddies were on the storm.

So, I watched things for a while and as the storms out east began to wane, my attention did as well. A few outflow boundaries rolled through the metro and I assumed one or the other was the expected cold front.

I was wrong, however. I was actually beginning the motions of getting ready for bed when I thought to check the radar again. It was close to 9:30PM at this point and I was very surprised to see cells firing all over the north side of the Metro. I activated the lightning net and decided to walk up the street to see if I could shoot some lightning.

There were a couple cells going up to the southeast and there is a lot by my new apartment which yields good views to that direction, so I walked there. Unfortunately, those cells quickly died and I focused my attention on those on the north side which were acquiring a lot of strength. I walked up to East Caley Avenue and South Syracuse Way where I stood atop a parking garage which had a good view to the northwest and began to shoot lightning. I was pleased with this new found perch as aside from having a great view, there is also nice fountain in the foreground.

I ended up taking quite a few shots as the storms strengthened and moved south-southeast along the Footies. Finally, I started to get some cloud-to-ground strikes, though they were distant.

As the storm approached, I began to see green flashes along the leading edge. My first thought was power flashes but upon checking my phone, the storm was only severe warned. I dismissed these flashes as lightning behind the precip core and continued photographing. Occasionally, I would see some interesting as we like to say, "hangy-downies" (I'm not taking credit for that one, I heard it elsewhere) but for the most part, it all looked like outflow structure.

I eventually realized that this storm was quite the best. Storm structure became apparent and I was able to see some shelving and striations over the FFD precip core. Also, to its left I began to see a wall cloud. I realized at this point that the storm had become tornado-warned. In my head, I realized that one couldn't chase a tornado-warned storm on foot! ... check out the wall cloud on the photos below!

I popped off a few more shots and as the precip began, literally sprinted back to my apartment. Radar at the time:

Image courtesy of IPS Meteostar

Time was of the essence as I made the decision to get in the car and head south, to either get ahead of or core the storm. So, I was soon on the road. Traveling south on I-25, the meso looked amazing. I wish I could have come out of the light precip enough to set up a nice shot ... the wall cloud was lit up very well by the city lights as well.

I got off the highway at Lincoln and headed west, but found myself lost in trees and hills and without a good view. I returned to I-25 and stopped again at the Happy Canyon exit where I filmed some "interesting structure" coming up from the north-northwest. The precip quickly caught me again and I continued south to Castle Rock where I set up in the parking lot of the outlets and tried to shoot some lightning/structure photos. Unfortunately, the outflow was quickly upon me and the wind in addition to the rain made shooting lightning very difficult. My tripod was all over the place and droplets of water blurred the lens. I did manage to get one CG before the deluge began, though the foreground is awful.

At this point, I realized the storm was outflow in nature and decided to core it and get on the backside for some lightning shots. As I got on the highway, I spoke with Tony Laubach who was in the midst of heavy damage in the Wheat Ridge area. I decided to head up there and check things out. I spoke with Scott Hammel as well and he decided to meet me up there.

However, I had to get through the core first! As I left Castle Rock, the visibility went to zero. The rain and wind were driving right into me and I could hardly see a thing! I continued on while all the traffic pulled over to the side of the road. There was a little hail mixed in but it wasn't large. As a reminder of the poor conditions of my tires, I was hydroplaning like a boat ... it was a bit hairy at times.

Eventually, as I descended down into the metro area, I came out of the precip and continued north to 6th Avenue where I headed west to Kipling. Right after the Wadsworth exit, I found massive hail drifts on the side of the highway accompanies by some serious hail fog. I pulled over to grab some quick video and took in a deep breath of the hail shred. The aroma was very intense.

I got off the freeway (6th) at Kipling and turned north. The streets were covered with hail and foliage and the power was out. It didn't help that the hail fog was very thick as well. I continued slowly north noting some minor tree damage ... a few big branches down here and there. As I approached 13th, a fire truck straddled the road in front of me. I turned off into residential streets and ended up in a bowling alley parking lot just west of Kipling on Colfax. There, I talked to few witnesses who endured the storm. Most reported crazy wind and hail with a few mentioning a funnel cloud. By the time the conversation was over, they had all begun saying that they had seen a tornado ... which I thought was interesting. Funny how their stories changed after talking to one another. "Oh yeah, I saw that too!"

I sifted through the hail looking for the larger stones. Though the amount was high, most stones were smaller than 1.25".

Scott finally made it through the closed streets and was in the 1st Bank building parking lot to my northwest, so I joined him over there. We found a tree that had been toppled and another that had been moved into the middle of the lot! Eventually we found a hole in the ground where the latter had come from, but for a good while, we were searching!

I noted that most of the leaves were stuck to the north side of the buildings and other objects. The tree that had been uprooted came from the northeast corner of that building. The grass on in the landscaping was all laid down from north to south; the damage was all rather uniform.

We stayed out and surveyed damage for another hour or so. I bisected the damage swath a couple of times and found that all the broken trees had fallen in the same direction. ... and there were plenty of those ... on vehicles, power lines, etc. The place was a mess. I went as far south as Alameda and as far north as 38th. The hail was common inside the swath and although there were reports of a tornado in the vicinity, I could find no evidence to support that. The only anomaly to the damage pattern was a window broken on the north side of a building on Colfax. However, most of the glass was on the outside of the window.

Eventually, I gave in to my horrible headache and my wake-up time of 6AM and headed on home. I arrived just past 2AM to find that I had left the north facing windows of my apartment open. Needless to say, I had to set up a fan do dry the carpet before I could get some shut eye.

I did take a look at storm reports and saw that there was a tornado reported in Englewood:


I was in Castle Rock at the time and the storm was WELL past Englewood. I noticed that the local WFO took the report out of their LSR today, so it may have been bogus.

Also, there was this one:


... which happened after I left Castle Rock and cored the storm. So, maybe it wasn't outflow-dominant at the time as I thought. With that said, there was tons of low cloud structure with this storm an it's entirely possible this was scud. It is hard to say for me as I didn't see the report in question. My attention at the time was turned to the north anyway.

So ... going back to the power flashes, I think they were on the leading edge of the massive RFD hail downburst that swept through the west side of the metro. Given that it was night, it's impossible to rule out a tornado, I just can't find evidence (other than reports of a funnel cloud) to support it. I've analyzed some of my lightning photos from the time and was able to see some power flashes along the ground as well as some possible funnel clouds (again, very hard to say as I was quite far away ... I'm just trying to substantiate the reports of a funnel in the area at the time). You'll want to click the image for a much larger version.

So wow! What a fun night ... the whole city is talking about the storm today and the damage was actually quite incredible. Thanks to the cold front which actually came in later than I thought, the lapse rates went through the roof and though the winds were out of the north before the front, as it passed, we achieved a slight easterly component aiding the general upslope and we really saw the topographical forcing along the Footies where we had been capped all day.

For a weather geek such as myself, it was a very exciting and satisfying day. It will go down for me as the day I "chased a tornado-warned supercell on foot" ;)

Mileage: 82 (only 0.5 on foot)
Largest hail: 1.25" (after the fact)
Major tree damage, moderate structural damage, some flooding, hail fog, wall clouds, etc.


July 20th Denver Severe Weather

Just a quick note to mention that I was out shooting lightning last night when the big storm hit the west side of the metro. I intercepted it in Castle Rock before heading back into the city to survey damage. Pics and a full report will be up later tonight. Please check back!


Sunday, July 19, 2009

2009 Storm Chase XXX Report - July 18th - Chinatown

Well ... this is one of those reports you really don't want to write and probably can get away without mentioning ... but for the sake of record keeping, here we go.

Okay, so I'm relatively low on funds until the beginning of August. That's what moving will do do you apparently! Anyway, after seeing some of the great storms and hail! in Colorado on Friday, I was itching to get out. Tony Laubach was nice enough to let me come along with him. I was less enthusiastic about severe probs for the day as the models kept putting a bubble of inhibition over NE Colorado ... around the bubble, however, was ample instability. The wind fields at the surface were a bit weak but there was enough moisture to do the job.

We met at the DIA park-and-ride at 2:15 and decided to head NE to intercept a lone storm moving in from Nebraska. I was a little weary about the storm as it was moving into the model forecast inhibited environment, but it was literally the only thing in the state. We ran into Scott Hammel in Bennett and it was cool to meet him.

We convoyed up and headed north on CO 70 to Prospect Valley all the while watching the storm die. We continued east a bit on CO 52 just north of Hoyt as the storm completely collapsed. I didn't even take a picture of it.

Doing a bit of mesoanalysis, I was stunned. There was virtually no inhibition and CAPE aplenty, especially back along the Footies. Looking in that direction, however, it was just hazy with a few altocumulus clouds. We made the decision to head back toward Denver, while keeping an eye on the mountains. As we appraoched the metro area, a skinny tower went up over Larimer County, but orphaned its anvil. That was the last time anything happened in the vertical. I was home by 6PM.

I was a little perturbed when I got home ... we *SHOULD* have had storms ... both the local WFO and SPC said "supercells" coming off the mountains. Nothing. I pulled our 0Z OBSERVED sounding and it shows the answer. We see temperature inversions at 650mb and 460mb.

There was a good deal of heating over the mountains of Wyoming yesterday. It's common in the summer to see warming in the mid levels due to heat transport along the mountain sides. Combine that with the northwest flow (would not have been different under zonal conditions) and that warm layer moves out over the plains. Now, sometimes when the sun goes down and this warming ceases, we can get an evening initiation ... but you also have to understand that the surface inversion begins at that time as well. No luck yesterday in that manner, but at least I feel a bit more at peace knowing what happened. I guess, the models just didn't see this mid-level inversion or at least didn't note its strength.

Mileage: 167
Quote of the day: "Forget it Jake, it's Chinatown".

Wednesday, July 15, 2009

2009 Storm Chase XXIX Report (Day Four) - July 6th (2009 Montana Summer Vacation Day Five) - The Long Way Home

I'm not going to lie. I sometimes have difficulties with self control. I suppose a part of me fantasized about maybe intercepting a storm or two on the way back to Colorado. However, as the morning that I planned to leave Montana rolled around, it soon became apparent that the chances of severe weather were actually really decent. SPC seemed to agree (it's not often that you see a 5% tornado risk in the MOUNTAINS of Montana).

As my time for departure neared, there wasn't a cloud in thy sky anywhere in Western Montana. I got anxious and spent a good deal of time debating the situation, counseling with my cousin to whom I was responsible for driving home on that day. The ever-agreeable Brian was of course on board for storm chasing if that's what the day called for.

I realized that I had only seen my grandmother once on the trip so I figured it would be a good idea to see her for lunch. So, along with my parents and cousin, I had lunch at Mackenzie River Pizza Co. and watched the storms blow up around us. The explosive cumulus development was impressive to all parties including my parents who remarked about the intensity of the storm. As we finished lunch, I watched an updraft over the city begin to lower before ascending Rampart Mountain on the northwest side of the city.

It was time to go.

Road options are not easy in Montana and I didn't want to get too far away from the route home, so after fueling up, I elected to take I-90 east over Homestake Pass. The storms were moving to the northeast and unfortunately, nothing developed south of my line. I knew the best chance of tornadoes would be some place between Great Falls, Helena, and Lewistown, so I made my target right in the middle, that being White Sulphur Springs.

As we approached my north option (US 287), a supercell northwest of Helena went tornado-warned. Unfortunately, I was completely out of position to intercept. By the time we reached Townsend, a nice storm was beginning to take shape over the southern portions of Canyon Ferry Lake (Reservoir). In fact, I found a nice vantage point and got a shot of a sweet meso:

I wanted to stay ahead of the storm, fearing I'd lose it due to road options and actually get an intercept, so we headed up into the Big Belt Mountains on US 12 where I lost data for more than a half hour. By the time we emerged into the next valley, I saw that the storm had basically stalled and been overtaken by the fast-moving shortwave squall. There was more convection popping in the mountains in the vicinity and the best tornado parameters were still near Lewistown, so we kept on, ahead of the storms.

After passing the Castle Mountains and fueling up in Harlowtown, we were northbound on US 191 and headed for Judith Gap (between the Little Belt Mountains and the Big Snowy Mountains). The western sky became increasingly dark as the storms approached and on radar (when I finally got a scan again as I had lost it outside of WSS), it had all become one linear mess. Already through the gap, there was no real point in turning back. I figured we could at least core the line on US 191 or possibly at the junction with US 87.

As the line moved out of the Little Belt Mountains, a nice shelf cloud began to set up. We stopped briefly for pictures and then again for a good deal longer as the outflow passed by.

And from our second stop ...

Brian takes a picture of a bit of a lowering in a kink in the line.

The line passed without much incident; basically only a wind shift. The CG's were impressive but I was mainly focused on the shelfy outflow structure. I wanted to get back ahead of the line, so we continued north and then east on US 87. Though there wasn't much precipiation at this advanced portion of the line, there was a lot of dust beginning to get kicked up. I tried to get ahead but unfortunately was hampered by road construction. 87 was compltely dug up and we were on dirt for a good length of time.

We soon found ourselves a good ten miles behind the outflow line and just west of Lewistown. I noticed some interesting structure to our north, so I pulled off and had a look. It was a very strange, laminar feature which appeared to be rotating in place. It was very cool to see the clouds racing overhead while this feature stayed completely stationary to our northwest. I'm still not exactly sure what to think of it ...

I was actually able to intercept the feature on dirt roads and sat under it for a while as it slowly dissipated. I do have some video but that will have to wait until later. Anyway, we returned to US 87 and saw some more interesting structure over the Little Moccasin Mountains. The coloring was gorgeous and because of the precipitation, I was unable to break out the tripod and had to settle from a hand-held low-light shot. Damn, I wish I would have tripodded it ... I think it would have been stunning.

Back on US 87, we were in heavy precip and the leading edge of the line was becoming distant ...

We drove through Lewistown and up into the Judith Mountains where we encountered some strong wind and heavy precip, but no hail. On straight roads in the flat eventually, I hoped to catch up to the edge, but by the time we reached the south option at Grass Range, we were just behind it. At this point, I was pretty much determined to leave the storms behind and begin the trip to Denver ... it was early evening and we still had ten hours to go.

We did encounter a very strong storm north of Roundup. The wind was absolutely insane and completely perpendicular to the road. I would estimate it at at least 50mph ... hard to say, though. The lightning was fantastic as well. Took some video ...

Anyway, as we approached Billings, there were two cells staggered back to the west (obviously behind the line) ... just found them pretty in the late evening light.

We met my cousin Brad in Billings for dinner and then headed back to Denver, arriving just after 5AM. All in all, it was a long day, but a fantastic home state chase.

Chase mileage: 369
Chase partner: Brian Macumber
Highest Wind: est 50mph
Hail: None
Structure: Mesocyclone, shelf cloud, other