AWUS01 KWNH 042131
FFGMPD
WVZ000-OHZ000-KYZ000-INZ000-ILZ000-MOZ000-ARZ000-050330-

Mesoscale Precipitation Discussion 0027
NWS Weather Prediction Center College Park MD
430 PM EST Wed Mar 04 2026

Areas affected...Portions of the Middle MS and OH Valleys

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

Valid 042130Z - 050330Z

SUMMARY...Showers and thunderstorms will gradually increase in
coverage and intensity late this afternoon through the evening.
Due to locally saturated soils from antecedent rainfall, the
additional moderate to heavy rain will promote a new threat for
areal flooding and localized flash flooding.

DISCUSSION...The latest GOES-E IR satellite imagery, radar, and
the 21Z mesoanalysis indicates a stalled frontal boundary and
effective outflow composite draped across portions of the Middle
MS and OH Valleys with increasing coverage of locally heavy
showers and thunderstorms. The convection is refocusing along
these boundaries ahead of an approaching shortwave trough.

Diurnal heating and an increasing southwest low-level jet (30 to
40+ kts) ahead of surface low pressure over central MO is
enhancing the regional pool of moisture and instability, with
MLCAPE values of 1000 to 1500+ J/kg and PWs of 1.2 to 1.4 inches
riding up across southeast MO through southern IL, southern IN and
western KY.

This more favorable thermodynamic environment coupled with DPVA
associated with the approaching shortwave and the low-level jet
aiming into the aforementioned surface boundaries should promote
increasing coverage and intensity of showers and thunderstorms
over the next several hours. Based on a combination of satellite
and radar data along with the HREF/REFS guidance, rainfall amounts
going through mid-evening may approach 2 to 3 inches. This will be
facilitated by some episodic training of convective cells and an
environment conducive for rainfall rates to reach 1.5 inches/hour
with the stronger and more organized thunderstorms.

The recent rainfall across at least portions of the OH Valley
(especially central/southern IN, southern OH, far northern KY and
western WV) has lowered FFG significantly over the last 24 hours
and increased streamflows. The 18Z HREF guidance shows the
additional rainfall this evening driving peak 3-hour FFG
exceedance probabilities of 20 to 40 percent over south-central IN
into southwest OH. Somewhat lesser probabilities are noted back
into southeast MO and southern IL, but in general, a combination
of the antecedent environment and additional rainfall is expected
to drive concerns for new areal flooding and localized flash
flooding. This will include potential for urban runoff problems as
well.

Orrison

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

ATTN...WFO...ILN...ILX...IND...JKL...LMK...LSX...LZK...MEG...
PAH...PBZ...RLX...SGF...TSA...

ATTN...RFC...KRF...MSR...ORN...TIR...NWC...

LAT...LON   40138323 39918160 39338067 38308097 38028187 
            38028458 37618680 37218819 36329031 35769219 
            35859315 36379345 37009298 37919076 38958891 
            39668730 40068548 40128450