Mesoscale Precipitation Discussion 0780
NWS Weather Prediction Center College Park MD
824 AM EDT Sun Jul 19 2026
Areas affected...in and near Middle TN & portions of AL
Concerning...Heavy rainfall...Flash flooding possible
Valid 191223Z - 191823Z
Summary...Showers and thunderstorms are beginning to develop
across portions of the region. Hourly rain amounts to 2.5" could
lead to isolated flash flooding.
Discussion...Convective activity is forming across Middle TN and
portions of eastern AL within a region of confluent 850 hPa flow.
Gulf moisture has taken the long way around and is invading from
the north; precipitable water values are 1.75-2" per GPS data. MU
CAPE is 1000-2000 J/kg, and MUCIN has recently been decreasing.
Effective bulk shear is roughly 15 kts.
The expectation is for CIN to erode and convective expansion to
ensue by 15z. As thunderstorms grow in coverage, incidents of
cell mergers and cell training are possible, which in this
environment could lead to hourly amounts to 2.5". Isolated
occurrences of flash flooding would be possible, most likely in
urban areas.