Mesoscale Precipitation Discussion 0131
NWS Weather Prediction Center College Park MD
725 PM EDT Tue Apr 02 2024

Areas affected...Portions of the OH/TN Valleys into the Central
Appalachians

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

Valid 022325Z - 030525Z

SUMMARY...Broken clusters of heavy showers and thunderstorms will
continue through the remainder of the evening and into the
overnight hours. A combination of heavy rainfall rates and locally
sensitive/saturated soil conditions will likely result in at least
scattered areas of flash flooding.

DISCUSSION...The late-day GOES-E IR satellite imagery in
conjunction with dual-pol radar shows broken clusters of heavy
showers and thunderstorms advancing across portions of the OH/TN
Valleys, with the more organized/stronger convective cells seen
focused over areas of northern KY and southwest OH, with
additional corridors of stronger storms also noted moving up from
central TN into southeast KY. The activity continues to be driven
by instability pooling northeastward well ahead of a cold front
and with a relatively moist southwest low-level jet of 40 to 50
kts in place.

MLCAPE values over northern KY and southwest OH have risen to as
much as 1000 to 1500 J/kg, with somewhat lesser values noted
farther southeast over eastern KY and WV where earlier convection
has acted to stabilize the boundary layer to an extent. Over the
next few hours, some resurgence of instability off to the
northeast back into areas of the central Appalachians is expected,
and with rather strong effective bulk shear parameters still in
place and deeper layer forcing arriving ahead of the upstream
upper-level trough, at least broken coverage of heavy showers and
thunderstorms can be expected.

Recent HRRR runs coupled with the experimental WoFS guidance
suggest rather strong confidence in continuing to see some linear
swaths of heavy rainfall associated with locally training areas of
convection. Rainfall rates embedded within the stronger and more
organized bands/clusters of thunderstorms are expected to reach
1.5" to 2"/hour heading through at least the remainder of the
evening hours while instability and shear remain conducive for
organized and sustainable updrafts. Thus, some additional rainfall
totals may reach as high as 2 to 4 inches heading through at least
the midnight time frame.

Many areas across especially central and eastern OH, northern KY,
central and northern WV, and western PA will be very sensitive to
the additional heavy rainfall threat over the next several hours
given how wet/saturated the soil conditions are. There are likely
to be scattered areas of flash flooding as a result, with locally
enhanced pockets of runoff expected. This will include an urban
flash flood threat. Areas farther south down into southern KY and
northern TN will be a bit more tolerable to the additional
rainfall, but even here, there may be at least some isolated flash
flooding concerns given the rather high rainfall rates and pockets
of cell-training.

Orrison

ATTN...WFO...CLE...CTP...ILN...JKL...LMK...MRX...OHX...PBZ...
RLX...

ATTN...RFC...LMRFC...MARFC...OHRFC...NWC...

LAT...LON   41667971 40987861 39887896 38688017 37928114
            36828284 36398434 36338534 37088600 38248509
            39598353 40848221 41478113