June 19, 2016

John Allen was still providing forecast guidance for us, despite his team having returned home days earlier. Team Duck's Forecast:

"Day 1 Synopsis: A broad moist warm sector has developed in response to the northern plains low which is migrating eastwards, with a stationary warm front draped just sound of the Canadian border in northern ND and MN. Observed dewpoints in W MN are as high as the high 60s, low 70s, with some higher values closer to the primary low in ND. The lows movement will drive a cold front to surge SE over the course of the day, leading to a strong source of forcing for convective ascent despite a strong capping inhibition which exists thanks to an impressive EML plume that will lead to moderate instability (2-3000 J/kg). A midlevel jet responding to the low should provide 40-60 knots of effective deep layer shear suggesting organized supercells at least initially, though the capping may preclude large upscale growth. LLJ and turning in the 0-3km should foster a tornado threat as well. This suggests a reasonable play anywhere where dewpoint spreads can be minimized (leaning toward farther N), and with any stronger discrete cells likely to pose the greatest risk.

CAMs suggest updraft helicity tracks, though none that intense south of the border, but certainly enough to indicate at least transient supercells, though the HRRR struggles to develop mature cells and rather has a bit of a popcorn thing going on. This may be a response to analysis of convective suppression from the overnight MCS (and tornado warned storm this morning), and perhaps overmixing of the diurnal moisture profile. Models all break the storms out late, around 00Z, so this suggests plenty of time to get into place.

In terms of target, I would think somewhere like Willmar would be a reasonable play, maximizing both the forcing, instability and LL shear potential for a tornado shot."

June 19 was Brindley and my last chase on this trip after spending over 20 straight days chasing on a scientific project led by Anton Seimon and John Allen. We were exhausted and beat, having lost a vehicle and not achieved our primary goal of documenting a tornado. We had one last chase opportunity on the way home, however, and Brindley and I would play it solo as the other teams had already returned home from the field. We had a marginal shot at some supercells on a cold front setup in western and northern Minnesota. We hoped to catch something on the southwest end of the setup where storms would hopefully be more discrete and in better terrain, but potentially further removed from the better tornado parameters to the northeast.

Minnesota is dotted with thousands of lakes, which usually prove to be an obstacle for storm chasing, but sometimes provide the most onubstructed vanatage points. A storm rapidly matured to our west and moved directly at us.

The storm peaked with the inflow notch and lowering moving almost directly overhead. We were then blasted by outflow winds coming off the lake with sheets of rain.

Some more classic supercell sturcture started to take shape southwest of town.

Bowing RFD gust front:

Another attempt at a wall cloud but the storm was starting to look more ragged and shelfy:

Storms started to slowly weaken by evening as the capping closed in started to choke the storms. The evening light made for some photogenic bases, however.

Our F-150 rental shown here. The beloved van died days earlier in Montana when the transmission went.

We stopped for the night in Willmar and grabbed some pizza at the Green Mill, reminiscing about the tragic season.