178
AWUS01 KWNH 082319
FFGMPD
MOZ000-ARZ000-KSZ000-090500-

Mesoscale Precipitation Discussion 0409
NWS Weather Prediction Center College Park MD
718 PM EDT Sat Jun 08 2024

Areas affected...far Southeast Kansas through Southern Missouri

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

Valid 082317Z - 090500Z

Summary...Widespread showers and thunderstorms with rain rates
eclipsing 2"/hr will train across parts of far Eastern Kansas into
Southern Missouri this evening. Where the most pronounced training
occurs, more than 5" of rainfall is possible, and this will likely
result in flash flooding.

Discussion...Bubbling TCu with some Cb noted in the GOES-E visible
imagery near SW Missouri appears to be the first signal for what
could be a significant heavy rainfall and flash flood event
tonight. This convection is blossoming ahead of a southward
sinking cold front, aided by modest fgen in the RRQ of a distant
upper jet streak, and increasing low-level convergence as 850mb
inflow begins to surge from the SW at 15-25 kts. This ascent is
impinging into extreme thermodynamics to support heavy rainfall,
noted by PWs measured by GPS of around 1.7 inches, near the record
daily max according to the SPC sounding climatology, and SPC RAP
analyzed MLCAPE of more than 4000 J/kg. Ascent acting upon this
extreme environment should support explosive growth of convection,
with bulk shear suggesting organization into clusters or an MCS
during the next few hours as well.

The guidance is in good agreement that thunderstorms will rapidly
intensify and expand in the next few hours, with the surge of the
LLJ drawing the most impressive moisture and instability northward
to intersect the slow southward advance of the cold front. With a
broad ridge to the south and trough to the north, the area will
remain pinched in W/NW flow, and 850-300mb mean flow responds by
remaining generally from the W through the evening. As storms
develop, this indicates they will track along the front, and then
even more impressively parallel to the nose of the LLJ as it
intensifies. This has a two-pronged affect of intensifying
moisture flux (SREF 850-700mb flux to +3 sigma) while also driving
intense convergence for ascent. The slow veer of the LLJ will also
result in Corfidi vectors becoming increasingly aligned against
the mean flow later tonight, indicating a high potential for
backbuilding and enhanced training.

In the robust environment, rain rates have a 40% chance of
exceeding 2"/hr according to HREF neighborhood probabilities, and
it seems plausible that brief 3"/hr rates could occur, especially
in more organized clusters. Where these rates train/backbuild,
locally more than 5" of rainfall is possible as noted by HREF
probabilities reaching 25% for 5"/6hrs.

The setup appears extremely favorable for flash flooding, made
even more supportive by antecedent soils that are somewhat
compromised from 24-hr MRMS rainfall as much as 2" in SW MO, and
7-day rainfall from AHPS that is in some places above 150% of
normal. This has lowered FFG to 1.5-2"/3hrs, which has a higher
than 40% chance of exceedance in a broad area. This further
supports the likelihood of flash flooding, and with additional
rainfall possible even after 05Z, this first round could prime the
region for more significant impacts overnight.

Weiss

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

ATTN...WFO...EAX...ICT...LSX...LZK...MEG...PAH...SGF...TOP...

ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...NWC...

LAT...LON   38479379 38359214 37759041 37269001 36659005
            36429050 36409130 36589259 37089457 37619546
            38269508