May 31, 1999

Meade/Sitka, KS Tornadic Supercell

with special contribution from Ed Calianese

 All The Ingredients In Place


Northwest Oklahoma/Southwest Kansas


Red polygon on image (click to enlarge)
shows our target area

 Surface Analysis 1500 UTC 31 May 1999

We started the day in Hays, KS. The surface chart showed a synoptic-scale low stretching from the northeast TX Panhandle across northwest Oklahoma.

Boundaries included a quasi-stationary frontal zone across the same area and an outflow boundary from a thunderstorm complex that along the Red River Valley.

Dashed green shows isodrosotherms. Note the tongue of moist air wrapping across northwest Oklahoma in east-southeast flow.


 500 mb Analysis
12 UTC 31 May 1999

30-35 knot west to west-southwest flow over target area in the morning. This projected to about a 50 knot storm relative flow at 500 mb for projected storm motion.


OUN Sounding
12 UTC 31 May 1999

Of the raob sites available in the target area, none was in the moist tongue. We felt Oklahoma City's sounding was most representative of the shear environment in the target area.


However, since OUN was to the east of the deep moisture, the moist layer was only skin deep.

The loop in the hodograph was indicative of the great low level shear. However, OUN's mid and lower mid tropospheric wind flow was not representative of what we expected further northwest.

Insertion of the stronger winds from 700 mb up, produced a hodograph quite favorable for classic tornadic supercells.

So, we were expecting tornadoes this day.


 ETA 12 h Forecast
Storm-relative Helicity
VT 0000 UTC 1 June

This represented the ETA's estimate of the "environmental" helicity. The best helicities were either in much drier air to the north, or the capped air much further south.

SREH in our target area was forecast to be around 100 m2/s2.


 ETA 12 h Forecast
VT 0000 UTC 1 June

This ETA view showed 3000-4000 J/kg CAPE, uncapped by 0000 UTC, in our target area. The combination of the large CAPE estimate, and weak-moderate SREH supported our initial target area.

We drove to Woodward, OK

Distant Meade Supercell --- From Northern TX Panhandle



This was shot just north of Perryton, TX

We drifted west from Woodward and watched the clump of towers west of Liberal explode into this beautiful storm.


Meade Supercell from Oklahoma Panhandle


Backsheared Anvil, Meade Supercell

The backshear became very prominent as we neared the northern portion of OK Panhandle.

Note the flanking line towers building into the main updraft.

 Wide angle view showing wall cloud and rear flank downdraft notch.

View looking due north near Meade, KS


First Meade Wall Cloud and RFD Notch


More Meade/Sitka Supercell Pictures