Monday, May 14, 2018

Late Afternoon Convective Trends

Convective development continues to increase near the northwest portion of the forecast area late this afternoon. This broken convective line extends from the Kansas City area into the Texas panhandle along a frontal boundary/dry line.

Day Cloud Phase Distinction RGB/Day Cloud Convection RGB/GLM Flash Extent Density

The airmass to the east of the boundary is becoming very unstable with surface temperatures near 90F and surface dew points near 70F. CAPE values on AllSKy LAP CAPE are around 3000 J/kg. However, a similar NUCAPS sounding suggests CAPE values near 5000 J/kg in the same area. These values are closer to those suggested by some high resolution guidance.

AllSky LAP CAPE
NUCAPS Sounding East of Dry Line
The main limiting factor for severe storms this afternoon is relatively weak shear, with bulk shear values  around 25 kts. However, shear profiles will increase somewhat over the next couple of hours as a weak upper-level disturbance interacts with the dry line. Some of this enhancement can already be seen with the development over the Texas panhandle.

Alex Brown

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