545
AWUS01 KWNH 010133
FFGMPD
TNZ000-MSZ000-MOZ000-ARZ000-OKZ000-010700-

Mesoscale Precipitation Discussion 0563
NWS Weather Prediction Center College Park MD
933 PM EDT Mon Jun 30 2025

Areas affected...Central AR...Southeast OK...Western TN...Northern
MS...

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

Valid 010135Z - 010700Z

SUMMARY...Very moist/unstable axis with favorable deep layer flow
for repeating/training cells.  Spots of 2-4" totals in
short-duration pose localized flash flooding through the early
overnight period.

DISCUSSION...RAP analysis shows deep layer convergence,
particularly along the upwind convergence zone along northwest
edge of 850mb ridge near mature convective complex in Southwest
OK.  A speed max of 20-25kts at 925-850mb is pressing eastward and
expanding the convective line into western AR.  The stronger
convergence connects up to the old outflow boundary from last
evening and intersects with the far southwest edge of trailing
confluence of the exiting MCV/shortwave in SE MO.  Total PWats are
well above normal in the 2-2.25" range throughout the axis which
further increases as westerly winds back to more southerly through
the MS Valley into W TN/NW MS; resulting in enhanced instability
pools of 2500-3000 J/kg across central AR and into the Delta
Region.

Northern stream trough is digging with warming in the GOES-E WV
suite across NEB entering KS/NW MO.   This will continue to
maintain stronger deeper layer steering flow parallel to the
boundary; though broaden the focus of convergence a bit more north
to south.  As such, 850mb winds will maintain and be more westerly
to support back-building environment with deep layer westerly flow
across AR.  So with stronger updrafts and very deep moisture,
vertical moisture flux could support 2-3"/hr rain rates; though
there is some uncertainty cells will order to train ideally for
sizable totals to exceed higher FFG values across SW to central
AR.

Convergence reduces across central to eastern AR before increasing
again where LLJ has turned more southerly through the MS River
Valley.  This will reduce favorable training orientation, but
stronger updrafts moving across reduced FFGs and recently
saturated soils across N MS and W TN may allow for widely
scattered 2-3" totals resulting in localized flash flooding
through the early overnight period.

Gallina

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

ATTN...WFO...JAN...LZK...MEG...SHV...TSA...

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

LAT...LON   36328880 35908822 34908833 34098899 33929084
            33839179 33759310 33809478 34469514 35089450
            35179264 35449106 36249019