From Mike Powell@618:250/10 to All on Fri Sep 11 09:33:46 2026
AWUS01 KWNH 111253
FFGMPD
ARZ000-111800-
Mesoscale Precipitation Discussion 1247
NWS Weather Prediction Center College Park MD
852 AM EDT Fri Sep 11 2026
Areas affected...Central to Northeast AR
Concerning...Heavy rainfall...Flash flooding possible
Valid 111252Z - 111800Z
SUMMARY...Slow-moving areas of heavy showers and thunderstorms
will maintain a threat for mainly isolated areas of urban flash
flooding going through early this afternoon.
DISCUSSION...GOES-E WV suite shows a well-defined mid-level
shortwave trough amplifying into portions of the Lower MS Valley
and Mid-South which is driving an axis of rather slow-moving
showers and thunderstorms across central to northeast AR.
Shortwave dynamics/DPVA interacting with a nearby quasi-stationary
front and pool of very moist and relatively unstable air should
continue to support a convective threat over the next several hours.
MUCAPE values of 1000 to 1500 J/kg are noted, with PWs of 2.0 to
2.25 inches, and this will easily support rainfall rates as high
as 1.5 to 2.5 inches/hour with the stronger storms. There is also
an environment conducive for some back-building cells with weak
and locally opposite upwind Corfidi vectors relative to the mean
layer flow, and this will also support elevated and locally
persistent high rainfall rate potential.
Satellite and radar data shows some of the back-building
convection occurring west of Little Rock, and the latest hires
multi-model consensus suggests some additional rainfall potential
over the next several hours as high as 3 to 4+ inches.
An isolated threat for mainly urban flash flooding will exist
going through the early afternoon hours as this shortwave energy
transits the region.