Tornadic environment on 3/27/04 in KS and OK: strong
shear/CAPE combinations and localized low LFC heights
(A short case study by Jon Davies, Wichita, KS)
On 3/26/04, I gave a talk at the Iowa Severe Storms Conference in Des Moines about research I've formalized regarding how significant tornadic supercells tend to "prefer" lower LFC heights. The very next day (3/27/04) was a good operational case example of this in west central Kansas and northwest Oklahoma.
A large F3 tornado with a 10 mile track north of Kinsley KS (see DDC storm
report) was captured on video shortly after 1 pm CST by storm chaser Lance Ferguson of
KWCH-TV (Wichita), who was in position early near the dryline in southwest Kansas:
Several short path tornadoes from the supercell south of Woodward in
northwest Oklahoma were also observed mainly after 1 pm CST, including this one:
Images and SPC mesoanalysis page graphics below show the tornadic storms, surface scenario, and environment characteristics at early afternoon on 3/27/04 (click on thumbnails for larger images). Note that the area of low LFC heights (<1500 m, implying rapid near-surface parcel ascent and large low-level humidity) and related axis of low-level CAPE fit well with the location of tornadic storms and tornado tracks (roughly 1900-1930 UTC), given that shear/CAPE combinations were significant (0-1 km EHI values 2.0-3.0) and favorable for low-level mesocyclones:
<1745 UTC 
<1900 UTC 
<1845 UTC
<18 UTC EHI
<19 UTC LFC
<18 UTC 0-3 km CAPE
<1926 UTC radar
12 hr RUC forecasts from 09 UTC valid at mid afternoon did a reasonable job of forecasting the large EHI environment co-located with signicficant low-level CAPE in the area where the tornadic supercells occurred (see Earl Barker's page as a source of RUC and Eta parameter forecasts):
<RUC fcst of 0-1 km EHI 
<RUC fcst of 0-3
km CAPE
The main tornado activity occurred early with the two cells noted above. The storms moved eastward away from the axis of low LFC heights and large low-level CAPE as the afternoon progressed, and this may have had something of a negative effect on tornado potential.
This case is another example emphasizing that awareness of environment characteristics can help meteorologists prepare for tornado warnings prior to development of notable radar characteristics. On this day, the main tornadoes occurred unusually early in the afternoon, and NWS Dodge City issued prompt tornado warnings near Kinsley based on radar and spotter reports, even though the Kansas tornadic cell was preceded only by a severe thunderstorm watch.
Jon Davies - 3/28/04