Mesoscale Precipitation Discussion 0485
NWS Weather Prediction Center College Park MD
226 PM EDT Thu Jun 19 2025

Areas affected...Central Arkasas...West-central Mississippi...Far
Northern Louisiana...

Concerning...Heavy rainfall...Flash flooding possible

Valid 191830Z - 200000Z

SUMMARY...Delicate balance of weak inflow and convergence to
maintain thunderstorms in a favorable slow/repeating steering
environment.  Fairly saturated upper-soils may result in increased
runoff and possible localized incident(s) of flash flooding.

DISCUSSION...Regional RADAR mosaic depicts the main core of the
outflow boundary from this morning's MCS continue to accelerate
southward across eastern MS/western AL as the core of the cold
pool presses south-southeastward starting to break out new
convection along its leading edge.  Upstream, however, the affects
of the cold pool are much less as the overall larger scale
forcing/shortwave slides northeast across the upper-TN Valley. 
Yet, the tail end of the cold front is hanging around with weak
northwesterly flow and drier air helping to tighten the theta-E
gradient across E OK into central AR.   Temperatures are nearing
90F whil Tds are in the mid to upper 70s, with ample pooled
850-700mb moisture noted in CIRA LPW along the intersection of the
outflow boundary to the cold front along the MS River.   CIRA LPW 
does note that mid-level drying has mixed in across the region and
the combination of slightly steeper lapse rates in this region has
bumped up MLCAPEs to 3000-3500 J/kg.  

The key will be prolonged/sufficient low level inflow/convergence
to maintain convective development.  Currently, VWP at LZK/SHV and
boundary layer cu tracers suggest 15-20kts of
confluent/convergence across central AR to help spark the initial
convective development. RAP analysis of bulk shear suggests
proximity of the mid-level flow is sufficient for 20-25kts to
maintain weak organization and while right entrance divergence is
best maximized downstream across the convective cores east of the
MS River, there should be enough tilt to allow for a few updraft
cycles. 

As noted, total PWat values are AoA 2" with the weak inflow
suggest solid moisture loading for 1.75-2"/hr rates, but updrafts
may still be fairly narrow.   However, with expected 10-15kts of
upstream confluence flow into the boundary layer, convergence on
outflows and deep layer steering along/just southeast of the
frontal zone should allow for some repeating/training potential.
Allowing for 2-3" localized totals.  While FFG seems to have
rebounded to normal/average values, the upper-soils remain fairly
saturated at over 60% per NASA SPoRT LIS products which are well
into the 90th percentile.  This suggests, given the intensity of
the rates, reduced infiltration and increased runoff potential. 
If the updrafts are broad enough, localized flash flooding is
considered possible through the afternoon. 

Gallina

ATTN...WFO...JAN...LZK...SHV...

ATTN...RFC...ORN...TUA...NWC...

LAT...LON   35059363 34839237 34409167 33469014 32818991
            32369058 33149241 33649331 34309422 34829424