April 15 2006 chase






4:42pm - i was on graveyards during this chase.  got myself to Lincoln well ahead of time to evaluate things.  the new model data showed the low would definitely punch south as advertised by the NAM for days.  i drifted over to syracuse for a bit.  a cyclonic arc of storms initiated, and i came back southwest to Adams to see how things evolved on the tail end (which was precisely where i wanted to be).  i waited too long, as the southern storm rapidly organized and tornadogenesis started early, regardless of my reasonings for hanging back (85-kt mid-level flow and high LCLs).  this may've been okay, but there were no paved roads in sight and i had to take a crappy gravel road south out of Sterling to try to get closer.  the terrain was very hilly, and the Beatrice tornado was likely ongoing as i caught glimpses of the RFB while struggling to find a good viewing spot.  when I did, the tornado must have just lifted.  i moved west a mile, found a large hill, parked, and snapped this photo.
4:58pm - the storm definitely had "the look" when i first saw it... with a pretty nice wall cloud.  however, the wall cloud dissolved and a high-based rear flank gust front surged forward.  i hoped the storm was cycling again.  then precipitation rapidly began to fill the downdraft area as the storm morphed into an HP supercell.  you know what they say about "the best-laid plans"...
5:00pm - NWSOAX storm survey indicated a continuous tornado track 34 miles in length from south of Beatrice through just north of Sterling.  if the "Beatrice tornado" did in fact remain on the ground before it wrapped in rain, I was too far away to observe this.  Regardless, tornadic damage apparently occurred within the developing heavy rain core beneath the mesocyclone.
5:01pm - Another shot of this nice HP supercell.
5:05pm - ditto.
5:07pm - ditto.
5:07pm - ditto.  it was impossible to discern whether anything tornadic was positively occuring in here, though this photo seems to show a truncated tornado "shape" way back in the rain... who knows
5:14 - The storm began to resemble the Knox county TX HP supercell from April 23, 2003.  Pretty remarkable to watch the heavy downdraft precip advance steadily north-northeastward in the field next to me.  Not long after this I headed back north to Sterling, somehow missing the worst of the rain and wind within the vault area.  The storm report says the long-track tornado dissipated 3 miles north of Sterling.
5:53pm - a final view of this storm's mesyclone as it moves away from me near Syracuse.
6:47pm - Looking west from I-29 near the IA-MO border at the next supercell down the line.  This storm produced a neat tornado near Julian NE 10 minutes earlier, per other chasers.
8:31pm - I continued southward and observed the next supercell in line from Amazonia MO.  It was a tornado-warned HP storm with a pretty nice sloped wall cloud tucked in the notch... some cloud base rotation appeared out of this, and just before the rain wrapped around the wall cloud it almost appeared as though a large funnel descended toward the ground.  Inconclusive to me what it was... maybe precip.  I headed south back home and the final storm in line was tornado-warned coming out of Leavenworth and Wyandotte counties.  The photo here shows the lightning-illuminated updraft approaching Kansas City north.  Only a couple of intermittent brief touchdowns occurred with this storm... supposedly one near 152 and North Oak, though this was never confirmed.



Weather data


00Z TOP RAOB (not really represntative of near-storm thermodynamic environments, but check out the shear profile...)

Sfc T/Td: 81/63 F

MLCAPE: 1794 J/kg

MLCINH: 62 J/kg

MLLCL: 1437 m

MLLFC: 2530 m

0-1 km SRH: 496 m2/s2

0-3 km SRH: 595 m2/s2