I worked a rather rare midweek afternoon shift at Van Nuys AP, and brought my camera with me. It was a bright and beautiful day with N to NW winds, great visibility, plus a few ACSL around. Don’t tell me that you don’t know that “ACSL” stands for “altocumulus standing lenticular” clouds. These wave clouds were courtesy of fast flow aloft over the Transverse Ranges of Southern California (northwest to northeast of Los Angeles). After a few obligatory airplane pics during the late afternoon, my camera lenses were turned towards the ACSL sunset. Enjoy!

I got rooms in Pierre, and on the way south a cluster of very strong storms matured west and north of PIR. We managed to squeeze ourselves in between several of these very electrified storms, and we had an amazing 4th of July thunder and lightning show! Lightning in these nearly stationary storms was practically continuous. At, Pierre, around midnight, Sioux Avenue had about a foot of water on it, and we had to find an alternate path to get to the Super 8!

The images above show the towering cumulus clouds southwest of Mobridge during the late afternoon.  (This was near Trail City and Promise.  Promise is a barely-there place along BIA 7 between Trail City and La Plant.  I think it is named after the yummy buttery spread.)  It was quite miserable in the sun, with a temperature near 90F and dew point of 77F!  We drove back and forth on the road for a time to try to stay in the shade of the clouds.  We were right on the front, too, and had little or no breeze.  What do you make of this line-up of hitchhikers?

We were somewhat despondent when nothing matured in our cu field near Promise, and we took the dirt road BIA 7 south to La Plant (in case a strong storm went up farther west on 212).  I took the first two images of the four above at 6:56 p.m. MDT (0056Z), from La Plant.  The cell was — you guessed it — practically right over Promise, SD.  A little more than 40 minutes later we were just southeast of the storm, along BIA 7.  Though we heard a pronounced hail roar, I think that the storm was already weakening at this point.  In the first image of the supercell (3741), a second strong updraft can be seen on the extreme right.  It is along the front and about 50 miles ENE of our nearby storm.

The lightning pics from Route 1804 about 15 NNW of Pierre are below.  I got a little artsy with the colorful sunset shot by jacking up the foreground brightness (the same image without the drastic photoshopping is also provided) —- it looks unnatural, of course, but I thought it was worth sharing.

Today offers good upslope chase prospects from about Weld County to Lusk and into se MT and nw SD. The question is WHERE exactly along this axis?? I wish I knew. We are headed west along I-90 towards the Black Hills. There are plenty of pros and cons favoring the south, middle, and north plays today.

After a look at the 12Z NAM, I liked the area from about Lusk to Crawford in the nw NE PH (the middle option). It shows a little wave at 500mb moving through that area. 500 winds are west at about 35 knots, above moist southeasterly surface winds. It isn’t difficult to image a nicely sculpted supercell moving southeast through this area around 00Z.

I checked the HRRR, and its 13Z run has a nice big blob down by CYS, moving slowly south into Weld County. This certainly could be a beast, perhaps tornadic. The HRRR kept this thing going while diminishing the cells in western SD and around the Black Hills, which seemed weird. This southern target is somewhat out of reach and is south of the 588 line at 500 mb), which scares me a bit. I would prefer to be on a storm north of that line! However, the latest RUC shows the highest forecast CAPE values around here, over 4000.

The 15Z RUC paints a very nice picture for extreme se MT and nw SD from 00Z to 03Z. Instability would appear to be excellent, and surface winds are forecast to be nicely backed as the RUC has a minor surface trough/lobe extending northeastward towards ne WY/se MT. 500 flow and 700 flow look just as good here as the NE PH vicinity, too. Some junky debris cloudiness in that area, though, will have to move out in order to make me giddy. This area is north of the hot air and that 588 line—yeah!

We will continue to RAP, and I’ll have to decide which side of the Black Hills to camp out on. At this point in time, I am favoring Harding County and vicinity in extreme nw SD.

After lunch in Wall, we continued west, and were lured into ne WY as storms were getting strong.  One very strong cell appeared to be a “left-mover”, as it was quickly moving north into Crook County.  I decided to try to intercept it along I-90.  This storm was moving north so quickly that we barely got to it by the time it reached I-90, and at that time it was crashing into another strong storm just north of the Interstate.  As this “merger” transpired, the low-level organization seemed to strengthen and a tornado warning was issued.  Lightning activity picked up suddenly, and we had some very suspicious lowerings just to our northwest.  Unfortunately, we were stopped along I-90 at a mediocre viewing spot, without a good view beneath the storm base.  We had no place to turn around, and had just exited a construction zone to boot, so we were lucky that we didn’t have to continue on the one lane into the core of the left-mover!  Anyhow, it looked on one or two occasions that funnel clouds were getting close to the ground some 5 to 8 miles to our northwest, and we were unsure whether a tornado had touched down or not.  Video and some of my still images (below) show some suspicious stuff!  We were about 8 to 10 miles wsw of Sundance.  SPC storm reports shows a 1.50-inch hail report ten miles west of Sundance, and no tornado reports.

This activity weakened some and was moving north into a poor road network, so we set our sights on a new supercell just east of Upton, some 25 miles to our south-southwest.  We headed south from Sundance on 585, thinking that the storm would move east or northeast.  While still 15 miles or so from the storm, we observed a pronounced wall cloud and funnel cloud with the storm base, and a spotter near the storm reported as much.  We tried to get closer after stopping for a few minutes, but the road tracked sse into a hilly area and we were unable to see what was going on to our southwest for a while.  Worse yet, the storm was moving little, and then sputtered and died once we found a hilltop to its east.  I really do not like chasing around the Black Hills.  Here is a shot of the Upton storm base to our south, a little bit after it looked its best:

With plenty of daylight remaining, we sprinted east toward some new stuff near and east of Rapid City.  This looked good briefly, but never got its act together.  We stopped near New Underwood to watch the storm move from our north to northeast, and then went into photo mode as the light and colors on the back of the storm were insane!

Today was the final chase day for the Tour 8/Doswell group.  The previous day featured the murk and messy nonsense in central and eastern NE, so I was ready to head out west for some pristine skies.  The outlook for severe weather along Colorado’s front range was rather slim, but the surface flow was upslope and moist enough for some high-based updrafts.  We made our way from Cozad to Limon and west to Interstate 25, between Castle Rock and Colorado Springs.  This is right along the Palmer Divide:  the elevated, favored area for storm formation on many late spring and early summer afternoons.  Given the “35-40 knots of deep layer westerly shear” here, according to SPC, I was hoping for a picturesque, isolated, rotating updraft.  Well, we got about four of them, one after the other!

Storm cells went up west of Larkspur (which is along I-25 north of Monument) and moved east.  We waited near the Interstate, and moved east a little with one or two of these.  The updrafts sputtered east of the Interstate due to a decrease in low-to-mid-level instability, and we headed back to the Interstate as the next pulse  strengthened over the mountains.

The first couple of cells were unimpressive, but the last two were somewhat strong (see images above).  I elected to place ourselves in the path of the core of the last supercell, and we caught a rainbow and some one-inch hail a little south of Larkspur.  I was going to continue east with this updraft, but then the sun came out and the light on the backside of the storm was quite nice.  We stopped on a hill on the west side of the Interstate a little north of Palmer Lake and set up the tripods.

As the junky convection approached, I had to decide whether to target the northern end (along U.S. 20) or the southern end (along U.S. 26). Both ends were showing some promise of organization. I went for the closer cell to the northwest, which was also closer to my original target area.

We made a quick pit stop in Manville while the storm strengthened overhead. An impressive CG barrage greeted us in Lusk as we pressed eastward to get ahead of the storm base. Finally, near the Nebraska border, we managed to get far enough in front to stop and take a look. The storm exhibited some supercell characteristics while we tried to stay dry right in front of it from Harrison to Crawford.

There is a forested canyon area just west of Fort Robinson, and we stopped on a high point on its west side to watch a nearby storm base. It had an area of weak rotation with a bit of a “pregnant” look, which sometimes precedes tornado development. As it moved nearly overhead, we had to bail to the east through the canyon, and were unable to see what was going on behind us for maybe 7 minutes. It was during this time frame that someone reported a tornado at about the spot that we had just been! When we reached an open area with a good view back to the west, there was no tornado—just a mediocre wall cloud (last two images above).

The storm was moving somewhat quickly to the northeast, and started to fall apart a little as it interacted with other junky storms. It wasn’t worth expending much energy to stay with. We raced east on U.S. 20 beyond Chadron to try to get ahead of another storm. It was mildly interesting for a bit, and then weakened. At Hay Springs, we were left with a little lighting and rain and a worked-over atmosphere, so we relaxed and had dinner. On our way to Valentine at sunset, the atmosphere gave us a good reason to stop and enjoy the western Nebraska sky! These colors are accurate and real-life — little to no photoshop enhancement was implemented on the images below!