Topeka, KS sounding

KTOP · 12Z Oct 15 launch · 270 m elevation

The 12Z Oct 15 launch on a Skew-T log-p, the key drawn on it. The hodograph is the wind through the lowest six kilometres, coloured by height: red near the ground, amber to three kilometres, green above. The 00Z Oct 15 launch is the faint trace behind it.

No instability. The column is moist. The freezing level is about 12,900 ft up.

CAPE: 0 J/kg · none
CIN: 0 J/kg · weak cap
LCL: 980 hPa · 17°C
Lifted index: 6.6 · very stable
K index: 34.9
Precipitable water: 44.1 mm

Reading a sounding

A radiosonde goes up on a balloon twice a day and reports temperature, humidity and wind all the way through the atmosphere. On a Skew-T the temperature axis leans right as you go up, so a parcel of air rising without exchanging heat - the faint purple lines - runs nearly straight up the page, and the gap between the red temperature trace and the green dewpoint trace is how dry each layer is.

CAPE is the energy a surface parcel would pick up rising through the profile: the area where the dashed parcel path sits to the right of the red trace. CIN is the energy holding it down first - the cap. The hodograph is the wind with height; a curve that turns clockwise with height is what rotating storms are made of.

Nearby launches

Omaha, NE Springfield, MO Dodge City, KS Norman, OK North Platte, NE Davenport, IA

Source: National Weather Service radiosonde observations for KTOP, via the Iowa Environmental Mesonet RAOB archive. Indices are computed here from the surface parcel and can differ from SPC’s.