Mesoscale Precipitation Discussion 0129
NWS Weather Prediction Center College Park MD
130 PM EDT Tue Apr 02 2024

Areas affected...much of KY and surrounding portions of WV, Middle
TN, and southern OH

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

Valid 021730Z - 022300Z

Summary...Narrow swaths of 2-4" of rainfall may occur through
mid-afternoon, possibly resulting in isolated to scattered flash
flooding.

Discussion...Relatively disorganized convection is ongoing early
this afternoon across a broad warm sector, encompassing much of
the MS/OH/TN Valleys. Some of the most efficient multicell
clusters have developed across the OH/TN Valley over the past
several hours, producing up to 1"/hr accumulations across portions
of northern Middle TN and south-central KY. This convective
activity looks to track into the wake of an earlier bow echo which
raced across portions of northern KY, southern OH, and much of WV
this morning, resulting in 0.5-1.0" of rainfall locally (and
pre-saturating soils across much of the region). The mesoscale
environment is characterized by 500-1000 J/kg of ML CAPE (and
increasing by as much as 300-600 J/kg over the past 3 hours),
precipitable water values of 1.1-1.6 inches (near or above the
90th percentile, per SPC sounding climatology), and ample deep
layer shear of 50-60 kts.

While convection within the open warm sector is expected to remain
somewhat disorganized through mid-afternoon (primarily due to the
lack of a focusing mechanism), cells may still take on an
increasingly linear orientation (from WSW to ENE with the deep
mean flow) that would allow for localized training through
mid-afternoon. This could result in narrow swaths as high as 2-4"
through mid-afternoon, as suggested by 12z HREF 40-km neighborhood
exceedance probabilities of 20-50% and 5-10% for 2" and 3"
thresholds, respectively. These totals would meet or exceed
associated short-term (3-hr) FFGs of 1.5-2.5", suggesting that
isolated to scattered instances of flash flooding are possible
(particularly over northern portions of the outlooked area, where
localized 0.5-1.0" totals occurred this morning).

Churchill

ATTN...WFO...ILN...JKL...LMK...MRX...OHX...PAH...RLX...RNK...

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

LAT...LON   39108161 38938060 37948045 37518155 37178259
            36758386 36348501 35898650 35908754 36558772
            37458707 38178590 38718424 38938289