AWUS01 KWNH 040920
FFGMPD
KYZ000-INZ000-ILZ000-MOZ000-KSZ000-041518-

Mesoscale Precipitation Discussion 0553
NWS Weather Prediction Center College Park MD
519 AM EDT Thu Jul 04 2024

Areas affected...Far Eastern KS...Central and Eastern
MO...South-Central IL...Southwest IN

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

Valid 040918Z - 041518Z

SUMMARY...Showers and thunderstorms with very heavy rainfall rates
will continue to spread off to the east this morning. Substantial
cell-training is expected to occur and additional flash flooding
is likely across central and eastern MO, with the threat also
spreading east across south-central IL. Locally severe urban flash
flooding is a strong possibility along a corridor extending from
Kansas City east through Columbia and down to St. Louis.

DISCUSSION...A significant band of training convection has been
aligning itself in a west to east fashion across areas of far
eastern KS and extending east across central and eastern MO.
Multiple major metropolitan areas are under a threat for severe
urban flash flooding as a result, including Kansas City, Columbia
and St. Louis.

The convection continues to organize and focus in response to an
approaching shortwave trough crossing the central Plains with
strong warm air advection out ahead of it. A southwest low-level
jet on the order of 30 to 40+ kts continues to nose up across
southwest to central MO and is focusing a corridor of robust
moisture convergence and elevated instability transport. Much of
the convection is embedded within an axis of MUCAPE values that
are on the order of 1000 to 2000 J/kg.

Going through the morning hours, the ongoing west to east band of
training convection should continue to propagate off to the east
and will be impacting more areas of especially eastern MO from
Columbia down through St. Louis, and also increasingly into areas
of south-central IL as the stronger axis of warm air advection and
forcing shifts off to the east across these areas. Eventually
areas of southwest IN may also get into some of this activity.

The rainfall rates should continue to be quite high, and capable
of reaching 2 to 3 inches/hour with the stronger storms given the
persistence of the low-level jet, high PW environment and degree
of instability that is in place.

Overall, the HRRR guidance looks notably underdone with its QPF
based on the latest radar and satellite trends, with the 00Z/06Z
HREF consensus appearing more realistic. Additional rainfall
totals going through mid-morning may locally reach 4 to 6 inches,
and with already sensitive conditions with moist soils and
elevated streamflows, flash flooding is highly likely over the
next several hours. As mentioned, there will be a threat for
severe urban flash flooding from Kansas City east through Columbia
and down into the St. Louis metropolitan area.

Orrison

ATTN...WFO...EAX...ILX...IND...LMK...LSX...PAH...SGF...

ATTN...RFC...LMRFC...MBRFC...NCRFC...OHRFC...NWC...

LAT...LON 39789352 39739052 39508860 39128725 38408653
37808705 37698974 38089370 38639492 39359487

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