Friday, July 14, 2017

7/11/2017 Mayville, ND HP Supercell and Tornado

(written by CoD Trip 5 assistant Evan Anderson w/ light editing)

Morning analysis depicted much more zonal UL flow this day with main UL jet strung across the northern tier of the US. As such, this resulted in a SFC low, maintained by subtle transiting s/wvs, at the 3-corner region of ND/MB/SK. Pendant WF sloped SSE across MN with a CF arcing WSW across ND into MT with a pendant dry trough/pseudo-dryline that jut out due south near the Devil’s Lake-Jamestown area. The latter likely ending up as our main focus for CI. Ahead of this feature was a rich moisture holding tight across the Midwest that would be advected to the NW through the warm sector. We had confidence this would occur as morning WV revealed yet another subtle s/wv in MT that would likely result in some p-falls across the Dakotas, deepening the main synoptic low, allowing winds to respond. Starting in Fargo gave us plenty of time to diagnose the situation and after a lunch at Space Aliens Cafe, we made our way to Mayville to do our second and final balloon launch. Data revealed a fairly classic loaded gun sounding with some weakness to the low-midlevel SR winds, but otherwise exceptional parameter space environment despite a potential hazard type of Severe and only 1 weak tor analog and a several non-tor supercell analogs.

Several morning runs of the HRRR beyond the 12Z run showed consistent CI along the dry trough by 2300Z and this ended up being quite realistic. CI occurred in a couple locations west of a line from Finley to Grafton shortly after our balloon launch had completed by 2100/2200Z, then arcing back toward the SFC low near the US/CN border. We navigated to Larimore and ended up being drawn north toward what was clearly at the time the strongest convection in close proximity to the better SErly sfc flow near the WF. However as we made our way north out of Larimore, convection filled in between a cell to our west and our target storm to our north near Grafton. A couple of these cells had even thrown off left splits that only further complicated navigation/cell interaction/nowcasting. Since we were under a 5% tor risk in GFK’s CWA…. Naturally and unfortunately – every – storm had a tornado warning, which only added to the confusion. By the time we finally cleared all other storm cores to get a view at the Grafton cell, the storm did not look impressive and nothing in the low levels on radar made us particularly hopeful. At this point we were considering pulling off for a secondary target and heading NW to intercept cells coming off the border. Only other option was to once again navigate storm/hail cores and blast back south toward a storm now at the southern edge of all the convection along the dry trough near Lairmore/Northwood. A short conversation with our most experienced nowcasters came back with a unanimous decision to get south. This ended up being a pivotal decision, not only because this ended up being the undeniable storm of the day… but the timing of our arrival was impeccable. We were able to get out ahead of the storm N of Mayville – W of Buxton while the storm was still exhibiting transient supercellular characteristics. But right as we made our first stop we started to see low level velocity data transition from less convergence to true azimuthal shear and the visual of storm absolutely confirmed that the storm was changing mode and becoming a true supercell.

Very quickly we started to see clear evidence of cloud base rotation and after a brief moment of considering whether to reposition before it produced the storm told us to stay put. The tornado touched down initially with very little condensation funnel evident, just a swirl of debris under the cloud base, but then had several rapid moments of full condensation within the tornadic circulation before becoming fully rain wrapped. We stuck with the storm until Halstead, MN, before conceding that the storm was in full HP beast mode and there was little chance to see another tornado – instead opting to drop south away from the storm and take in the impressive mid-level updraft structure.

At this point we called the primary chase effort to head to Moorehead to gas up (van 2 was in desperate need), and also to arrive at our hotel in Fargo to set up for what would certainly be a long travel day to the heart of the CN prairies for the end of the week. After arriving at the hotel, our storm had drifted well to our SE and was putting on a decent lightning show, so a large chunk of our group that was still willing to head out in the vans dropped SE of the greater Moorehead/Fargo area and shot some lightning that was unfortunately slightly obscured by a mid-level stratocu deck...but still enjoyable.

Timelapse forthcoming...

7/9/2017 Olivia, MN Explosion

We (CoD Trip 5) launched our first weather balloon from Sauk Center, MN, before heading south towards and absolute explosion of an updraft near Olivia, MN. Turns out, this rapidly developing supercell became quickly HP, and mostly caused us a lot of frustration as we struggled to maneuver around to the southern flank. We did stick with the storm until late in the evening, where we documented a brief tornado and vivid lightning. 

Tuesday, June 27, 2017

6/21/2017 Beaver City, NE Euphoria

Wednesday was just one of those days that will be hard to ever replicate. After a long afternoon/evening waiting for severe storms to develop in Norton, KS, we sat up shop just south of Beaver City, NE, to photograph convective towers and sunset. We were treated with nearly 5 1/2 hours of great skyscapes (e.g., sunlit towers, ACCUS @ sunset, continuous lightning, stars, Milky Way). We sat in the same spot (with only one car passing!) from 8:00 PM CDT to just after 1:30 AM CDT filling up memory cards with picture after picture for timelapse. We were definitely high on life! Another day I will never forget, and a great end to ACP 2017! 

Our position and bearing

Sunset facing west

Milky Way! 

Wednesday, June 21, 2017

6/20/2017 Ulysses to Big Bow, KS Severe Storms

Tuesday featured a targeted slight risk of severe thunderstorms across west central Kansas. We were not expecting any tornado potential as the dewpoint depression values were well over 30 F by late afternoon, but severe weather did form in our target area east of Leoti, KS. We saw some great structure on a developing quasi-supercell that produced 2.75" hail in several locations throughout its lifecycle. Most of the photos below are from near Ulysses, KS, with the exception of the railroad shot (one of my favorites from this day). That picture was taken near Big Bow, KS. We also documented wave breaking with a left split moving toward our location. Walker's timelapse of this should be outstanding...

We went through Ulysses after the storms passed, and it was easy to see the vegetation damage and even a snapped power pole north of town. Another amazing day in America's heartland! 

MISC: Overnighted in Garden City, KS. 

6/19/2017 Rio Grande River Gorge

We suspected the cap would be too strong for convection (given the limited upslope winds), so we spent our day bouncing around the Spanish Peaks. We spent some time in the very cool town of Taos, NM before dipping through the Rio Grande River valley and crossing the Rio Grande pass bridge. A day filled with great scenery, friends, and itchy chigger bites!

MISC: Overnighted in Trinidad, CO.

6/18/2017 Picture Canyon, CO and Raton Pass

On Sunday we took the opportunity to visit Picture Canyon (a small state park near Campo, CO) as we were passing through toward Trinidad. This location had some very neat pictographs and petroglyphs, They are believed to be artifacts from the Plains Indians (c. 1650). We then enjoyed a leisurely drive through the Raton Pass in northeast NM, stopping periodically to take in the sky. 

Overnighted in Trinidad, CO.

Tuesday, June 20, 2017

6/17/2017 Cosgrove to Wichita, KS Supercell and Shelf

Saturday’s setup was another typical 2017 setup, with outstanding instability but rather lackluster low-level wind shear. After killing some time in Salina, we drifted north to rapidly developing towers south of Junction City, KS. They had some good initial structure and were throwing out copious positive CG bolts, but cold pools quickly consolidated into a forward propagating MCS. We stayed ahead of the bow from Cosgrove to Wichita, occasionally stopping for photos of the shelf and attempts at lightning.

MISC: Overnighted in Wichita, KS

Saturday, June 17, 2017

6/16/2017 Tilden, NE Tornado and Fairmont, NE Skyfire

Friday was one of those chase days that comes around only a handful of times per year. Awaking in Hutchinson, KS, we eyed a potential target of Norfolk, NE along a gently drifting density discontinuity. After waiting in the (nice) Albion, NE park, we shifted north to developing cumulus congestus northwest of Norfolk. The initial cell had a distinct lowering from rain cooled air being ingested from the forward flank.  It continued to strengthen, and to our surprise, developed strong rotation and a brief tornado near Tilden, NE. Precipitation from a new cell to the west was too much to overcome though, and it was pretty clear from our perspective that the complex was becoming outflow dominant. We shifted to structure photography mode and began setting up for sunset and lightning opportunities. This really payed off, as we witnessed an absolutely spectacular lightning show just east of Fairmont, NE. This was a top 5 lightning show for me, filling up two 32GB memory cards with photos and timelapse images. As if it could not get any better, the sky was full of mammatus to our east, a pretty sunset to our west, and infinite numbers of fireflies dancing in the fields among us. A day I will never forget. Make sure to watch the timelapse until the end!

MISC: Overnighted in Lincoln, NE - Met up with Skip and Brindley for HUGE pizzas.

Strong rotation and a dust swirl near Tilden, NE (lasted 1-2 min)