895
AWUS01 KWNH 310055
FFGMPD
MSZ000-LAZ000-ARZ000-310630-

Mesoscale Precipitation Discussion 0352
NWS Weather Prediction Center College Park MD
854 PM EDT Thu May 30 2024

Areas affected...Central & Southern AR...Northern LA...

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

Valid 310055Z - 310630Z

SUMMARY...A narrow axis of unstable air downstream of decaying MCV
in W AR, suggests slow moving efficient showers with potential for
some stationary cells into overnight hours.  Stronger
thunderstorms capable of 2"/hr rates east and northeast of mature
MCS entering N LA similarly pose potential for localized 2-3"+
totals and possible flash flooding incidents.

DISCUSSION...A highly uncertain potential for highly
focused/localized flash flooding may occur through the early
overnight period across the discussion area.  A rapidly decaying
MCV, mid-scale shortwave from last night`s MCS continues to
progress eastward into western AR at this time. Along/ahead of the
wave through the southern and eastern quadrant, low to mid-level
highly confluent and moisture rich air continues to wrap back
toward the MCV with cells along the leading edge of the older
outflow boundary continuing to slowly advance.  Cells have modest
but sufficient instability up to 1250 J/kg of MLCAPE and 20-25kt
of moisture flux 1.5-1.75" TPW generally from central AR southward
into west-central MS and northern LA.  Cell motions will continue
to be very slow as the dying MCV slides southeastward into the
instability axis.  This may allow for small pockets of enhanced
deep layer convergence to support slow moving but deeper
convection as suggested by a variety of Hi-Res CAMs including
recent HRRR runs.  This may support SHaRS-type flash flooding
incident(s) with localized 2-3" totals resulting in possible flash
flooding, which are difficult to pinpoint and highly dependent on
some storm-scale interaction with the MCV downshear making
confidence a bit lower.

However, further south across northern LA and southern row of
counties of central AR, flow intersects with the more mature
MCS/MCV racing out of NE TX into NW LA; the effective warm front
has slightly higher moisture and instability and with stronger
convergence is supporting rates over 2"/hr.  Cells have some
meager training appearance through this axis in N LA to suggest a
stripe of 2-3"+ totals are probably resulting in possible
instances of flash flooding in the near term.

Gallina

...Please see www.wpc.ncep.noaa.gov for graphic product...

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

ATTN...RFC...ABRFC...LMRFC...NWC...

LAT...LON   35679303 35309220 33959128 32469112 31849171
            32089342 33109342 33669301 34589324 35309347