AWUS01 KWNH 031709
FFGMPD
TNZ000-KYZ000-INZ000-ALZ000-ILZ000-MSZ000-MOZ000-ARZ000-032307-

Mesoscale Precipitation Discussion 0111
NWS Weather Prediction Center College Park MD
108 PM EDT Thu Apr 03 2025

Areas affected...Mid-South into the OH Valley

Concerning...Heavy rainfall...Flash flooding likely

Valid 031707Z - 032307Z

SUMMARY...There will be increasing concerns through the afternoon
and early evening hours for increasingly significant and
life-threatening flash flooding from repeating rounds of heavy
showers and thunderstorms.

DISCUSSION...The early afternoon GOES-E IR satellite imagery in
conjunction with radar shows an extensive axis of heavy shower and
thunderstorm activity becoming a bit better organized and aligned
in a southwest to northeast fashion from central AR northeastward
through western TN and into areas of southern KY.

Compared to earlier this morning, the overall convective
orientation has been tending to gain some latitude as subtle
mid-level height rises over the Southeast U.S. becomes more
apparent and fosters a stronger poleward transport of warm air
advection and moisture transport ahead of the deeper layer
troughing over the central and southern Rockies. The airmass south
of a well-defined frontal boundary over the Mid-South has become
moderate to strongly unstable with MLCAPE values of 1500 to 2500
J/kg and remains quite moist with a southerly low-level jet of 30
to 40+ kts. The latest CIRA-ALPW data shows a substantial pooling
of moisture in the SFC/700mb layer with notably strong
concentrations noted from southern AR through northern MS.

The concern going through the afternoon and early evening hours
will be the gradual expansion and organized nature of heavy shower
and thunderstorm activity over areas that have already seen heavy
rainfall and flash flooding over the last 12 to 24 hours.
Streamflows across the region continue to increase and with
locally saturated soil conditions in place, the additional
rainfall signal that is coming out of the 12Z HREF guidance
suggests a growing concern for high-impact flash flooding.

Rainfall rates are expected to increase to as much as 1.5 to 2.5
inches/hour with the stronger storms, and especially over areas of central/eastern AR, northwest MS, and western TN where the
instability nosing over the aforementioned front is a bit
stronger. By early this evening, some additional rainfall totals
of as much as 3 to 5 inches will be possible. Flash flooding is
already ongoing across areas of western and middle TN, and with
the additional rains, significant and life-threatening impacts are
expected to gradually occur.

Orrison

ATTN...WFO...HUN...JAN...JKL...LMK...LZK...MEG...MRX...OHX...PAH...

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

LAT...LON 38458369 37868287 37078375 36028580 34928810
34019061 34069213 34889248 35529183 36219041
37058855 38158573
$$
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