Mesoscale Precipitation Discussion 0561
NWS Weather Prediction Center College Park MD
727 AM EDT Mon Jul 30 2018

Areas affected...Southeast OK, western AR, & northeast TX

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

Valid 301126Z - 301526Z

Summary...the combination of a warm advection band and an incoming
mesocyclone is expected to lead to hourly rain totals to 2.5" with
local amounts to 4" during the next several hours.

Discussion...A warm advection band has formed quickly ahead of a
mesocyclone moving into southeast OK and is showing increasing
rain rates in its vicinity.  MU CAPE values to its south have been
rising lately, and are now over 2000 J/kg.   Inflow at 850 hPa is
southwest at 20-25 kts per VAD wind profiles.  Effective bulk
shear of 25-30 kts is allowing for convective organization. 
Precipitable water values of 1.75-2" lie in this area per GPS data.

Mesocyclone maintenance/reformation, cell collisions, and cell
training are expected to be the main cause of heavy rainfall.  The
06z HREF probabilities of exceeding 1" an hour indicate that the
rainfall intensity within this band could remain high through 15z.
 It's possible the signal in the mesoscale guidance is a little
too far north as well.  Hourly rain totals to 2.5" with local
amounts of 3-4" have been implied by radar data, which seems
reasonable for future expectations given the setup.  The band is
progressing into an area of declining flash flood guidance values,
implying an increased threat of rain-related issues should these
rates/totals persist through 15z.

Roth

ATTN...WFO...LZK...OUN...SHV...TSA...

ATTN...RFC...ABRFC...LMRFC...

LAT...LON   35239614 35059465 33979305 33139398 34049553
            34839625