Mesoscale Precipitation Discussion 0308
NWS Weather Prediction Center College Park MD
844 AM EDT Sat May 24 2025

Areas affected...Southeast KS and Eastern OK through the Ozarks

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

Valid 241244Z - 241800Z

Summary...A sprawling MCS aligned north of a warm front will
continue to dig southeast this morning while only slowly
weakening. Rainfall rates of more than 2"/hr are likely at times,
leading to 1-3" of rain with localized amounts above 4". This
could cause instances of flash flooding.

Discussion...The regional radar mosaic this morning shows a large
swath of convection aligned WNW to ESE from southeast Kansas
through the Ozarks and into western Tennessee. This convection is
generally formed along the nose of a LLJ that is measured via
regional VWPs of 30-35 kts from the SW, feeding into the clusters
of thunderstorms to continue to fuel heavy rainfall rates
estimated via local WSR-88Ds of 2-3"/hr at times. This convection
is persisting just north of a warm front, so the LLJ is
additionally lifting isentropically to produce ascent beyond the
convergence along the nose of the LLJ. Additionally, an MCV is
noted in the reflectivity moving into NW AR, with the accompanying
convergence boundaries providing an additional impetus for
strengthening areas of thunderstorms, although a bow echo
developing

Over the next few hours, the high-res CAMs are in good agreement
that the developing bow echo will become the dominant feature as
the LLJ begins to veer more out of the west, helping to sweep out
the remaining convection from northwest to southeast. While this
will result in faster general motion and a slow reduction in the
flash flood potential, it will take several hours for everything
to propagate southeast out of the area. Additionally, a convergent
trailing tail west of this MCV/bow echo, noted already on
reflectivity across SE KS, could result in some backbuilding and
lingering heavy rainfall, despite more modest instability.
Rainfall rate forecasts from the HREF and 15-min HRRR continue to
indicate that 2"/hr or more are likely as everything dives
southeast, although the heavier rates will likely be within the
faster moving cells. Otherwise, there are moderate probabilities
(20-40%) for rates exceeding 1"/hr along the convergent bands, and
additional rainfall of 1-3" with locally more than 4" is expected.

3-hr FFG across this area is generally 2-4", for which the HREF
has a decreasing trend in potential for exceeding through late
morning. However, where the rainfall rates are strongest near the
MCV, or where multiple rounds can occur within the WAA downstream
of the MCV/along any convergent bands, both the HREF and REFS
suggest a 10-20% chance of exceedance, further indicating the
continued potential for at least additional isolated flash
flooding into the early aftn.


Weiss

ATTN...WFO...ICT...LZK...MEG...OUN...PAH...SGF...SHV...TSA...

ATTN...RFC...KRF...ORN...TUA...NWC...

LAT...LON   38129793 37889672 37559548 37349414 37049223
            36409057 35698979 34998938 34478944 34288987
            34279055 34309136 34449239 34369322 34239414
            34179495 34649580 35409653 36499697 37669796