Mesoscale Precipitation Discussion 0733
NWS Weather Prediction Center College Park MD
858 AM EDT Fri Jul 26 2024
Areas affected...Northwest MS...Southwest TN
Concerning...Heavy rainfall...Flash flooding possible
Valid 261257Z - 261657Z
SUMMARY...Locally slow-moving bands of heavy showers and
thunderstorms may yield some excessive rainfall totals this
morning. At least an isolated threat of flash flooding will exist.
DISCUSSION...The latest radar imagery shows a tightly wound
circulation/vort center focused up across far northwest MS in
close proximity to the TN border. Forcing associated with this and
interaction with a modestly unstable airmass characterized by
MUCAPE values of around 1000 J/kg is largely the main driver of
the convection, which also includes some modest moisture
convergence.
A look at the 12Z RAOB data down to the southwest around LZK
confirms a moist vertical column characterized by relatively tall
skinny CAPE profiles. And this along with the current satellite
character of the activity suggests relatively shallow/warm tops to
the bulk of the convective activity. This implies an efficient
warm rain environment which will be conducive to driving enhanced
rainfall rates.
MRMS data already suggests some rainfall rates of 1.5" to 2"/hour,
and there is some weak banding characteristics noted with the
convection along with slow cell-motions. This may favor some areas
over the next few hours seeing rainfall amounts quickly reaching
up into the 3 to 5 inch range.
The latest CAMs may be a little too quick to weaken this
convection going through the late morning hours given the strength
of the mid-level vort center, and so some longer duration of these
convective bands is expected.
Some isolated areas of flash flooding will be possible at least
over the next few hours, and this area will continue to be closely
monitored.