May 15, 2016 North-Central New Mexico Chase

by John Farley

The forecast:

For several days, forecast models had agreed on potential for severe weather, including supercells, somewhere in northern New Mexico. CAPE was forecast in the range of 1000-2000, and in some runs, above 2000 - plenty of instability for the high altitude of northern New Mexico. A dryline was predicted to form unusually far west, somewhere around the central mountain chain. East of the dryline, the aforementioned band of instability would set up, betweeen the dryline and cool, damp air behind a stalled back-door cold front. But the question was where precisely all this would set up. A few days before this chase day, models were indicating the instability in the center of the state, near the Rio Grande Valley and central mountains. But then for the two days or so before this event, the models had shifted to a more typical (for NM) event of the best instability being on the eastern plains, with the dryline perhaps just east of the mountains. This is the scenario that SPC and the Albuquerque National Weather Service both went with in their morning forecasts, with SPC favoring the best chance of severe weather in southeast NM. However, the morning model runs were again looking more like like a few days earlier, with the best instability in a N-S band through the center of the state. Also, most of the models, including the HRRR which is usually one of the more reliable for precipitation forecasts, were keeping virtually all of the precipitation north of I-40, and most of it north of a Santa Fe-Las Vegas line.

The Chase:

This would be the first of two days of severe storm observation for me, starting today in NM then shifting farther east the next day to somewhere likely in the TX/OK Panhandles. I decided to watch for a while, since I was starting out from Santa Fe and figured I might not need to go very far. By around 11, storms were forming over the mountains east of Santa Fe and northeast of Albuquerque, so I figured it was time to head out. The first storm I went after was near Galesteo, and it had a hail marker on radar and looked pretty good both visually and on radar. A picture can be seen here.

After a while of putting down some hail, locally heavy rain, and CG lightning, that storm weakened, so I decided to head for some storms I had seen over the Sangres between Santa Fe and Las Vegas. But I had also considered another storm that looked decent visually farther to my SW, initially developing somewhere near or just north of Moriarty. After I got a couple exists east of El Dorado on I-25, I noticed that the Morarty storm had a good-sized hail marker, so I decided to turn around and go after that one. I could only see the hail marker on the radar, because, on the lower scans at least, it was blocked by the mountains from showing up on the ABQ radar, and for some reason the Cannon AFB radar was not working on GRL-3. Shortly after I turned back toward it, however, the storm got a SVR warning, so I knew my decision had been right. The problem I now faced was that I was on the wrong side of the storm to get the best view of it, and it was moving toward my southeastward route, U.S. 285. To get a good look at it, I would need to beat the storm to wherever it crossed 285 and get to the south side of the storm. I barely managed to do so, getting some rain and a little soft hail as I cut through the far eastern edge of the core - with the heaviest rain and hail still clearly just to my SW. By the time I got around to the south side of the storm, I could see that it was a gorgeous LP (low-precipitation) supercell - perhaps, it turns out, the prettiest one I had ever chased (although the next day I would get another, perhaps even better). With LP supercells, the appearance of the storm is not to have much precipitation, often appearing to be mostly clear under the storm. However, there is actually precipitation there - you just don't see it as much because 1) the strong upper winds carry it farther away from the updraft and 2) much of the precipitation is hail, which does not block visibility as much as rain. And this storm was indeed a hailer, as it produced 1-inch hail not far from Stanley, NM, and undoubtedly larger and harder hail along 285 than that which I had encountered, after I managed to get through ahead of the storm.

Here is a picture of this LP supercell storm:

This only shows the bottom part of the storm - I was too close to get the whole thing in. Hopefully at some point I will be able to do a panorama stitch to show the whole thing, and will add that to this report if and when I do. I watched the storm until it had crossed the highway, then started south toward I-25 to try to re-position for another intercept. But in the rear view mirrors I noticed it was forming a wall cloud, so I backtracked and soon was looking at this:

After watching this for a while, I knew that if I was to have any hope of a re-intercept, I would need to drop south to I-40 and then back north farther east. Road networks are very limited here, so just going directly after the storm is often not an option. I thought I might be able to re-intercept by going east on 40 and then back north toward Villanueva. Sounded good in theory, but it turned out to be awful in practice. The road, NM 3, which runs north and south through Villanueva between I-40 and I-25, unlike the road I had been on, goes through hilly, wooded terrain - virtually impossible to see anything going on in a storm unless the storm is nearly on top of you. I kept hoping for a high spot or a clear area, but there were virtually none. And of course no data once you are 5 miles or so away from I-40. By the time I got to Villanueva, the storm had apparently dissipated, as I crossed all the way eventually up to I-25 without ever encountering the storm, or even wet roads until I got very near 25. Meanwhile, another supercell had formed northwest of the original one, just southeast of Santa Fe, dumping copious amounts of hail on I-25 between Santa Fe and El Dorado, causing serious traffic problems. Clearly that would have been the storm to be on now, but my unsuccessful try at re-intercepting the earlier storm had precluded any play at that one.

Since I wanted to get east for the next day's chase, I figured I would head over to Las Vegas, NM and see what was going on with the storms near there over the Sangre de Cristo Mountains, which had intermittently been SVR-warned. And then I could go on to Tucumcari to pre-position for the next day's chase. I drove around a little to the north of Las Vegas to see if I could see anything interesting with the storms, but nothing much seemed to be happening. So I went back to Las Vegas to get gas, where I ran into a chase tour group at the gas station and chatted with them for a while. After gassing up and other necessities, I got back in the car to start east to Tucumcari, when I noticed that a new SVR warning had just been issued for a storm slightly to the west of Las Vegas, including Las Vegas. I went back over to the other chase vehicle and asked them if they had seen that, which they had not, then took off to find a spot just north of town to view the storm.

The updraft of the storm was just coming over the mountains west of town, with very low inflow clouds being drawn into the storm in front of the mountains. CG lightning zapped down very close, and the rain/hail core soon was evident on the west slope of the mountains as the storm drew closer to town. I was in its path, so I backed away a mile or two south, back into the far northern part of the town. The wall cloud/meso passed just to my north, displaying weak rotation probably less than a mile from my location. After it passed and continued on its movement to the ENE, I pursued if for a while, and decided to take the back route (NM 104 as opposed to U.S. 84 and I-40) to Tucumcari to try to keep up with the storm. However, the road goes ESE and the storm was moving to the ENE. So after seeing some distant cloud tags extending to near the ground, which I got video of along with some lightning, I let the storm go and headed for Tucumcari. The low cloud tags appeared to be scud, not funnels, but there did appear to be a little weak rotation again in these clouds. But no road network that would allow me to keep up, and I did want to get to Tumcari in time to get dinner and a room for the night. So that was effectively the end of this day's chase, as I headed east and found a place to stay for the night in Tucumcari.

Here is my video of the Las Vegas storm:

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