Mesoscale Precipitation Discussion 0765
NWS Weather Prediction Center College Park MD
548 PM EDT Tue Sep 04 2018

Areas affected...South-Central Kansas

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

Valid 042148Z - 050200Z

Summary...Slow-moving thunderstorms may persist for a few hours
over a small portion of south-central Kansas, posing a risk of
flash flooding. Rain rates could approach 2 in/hr, and heavy rain
could last a couple hours in specific locations.

Discussion...Thunderstorms have become sufficiently organized into
small southwest-to-northeast oriented lines to pose a near-term
flash flood risk in south-central Kansas. The convective line
orientation was nearly parallel to the deep layer mean wind, and
within 10-15 degrees or so of the observed storm motions for most
cells in these lines. The convection was situated in a region of
broadly confluent low-mid level flow, and on the southern
periphery of a pool of instability. This should enable
thunderstorms to be sustained for another several hours, and given
the orientation of the convective lines, flash flooding appears
possible. While this area is just outside the primary plume of
high PWs pushing up the eastern Plains, it is within the western
periphery of considerably high PWs around 1.7 to 1.9 inches. Given
available MLCAPE around 1500-2000 j/kg, and effective deep layer
shear around 30 knots, this should be sufficient for somewhat
organized convective lines and clusters with rain rates around 2
in/hr in the strongest thunderstorms. This could cause flash
flooding if sustained for more than an hour, and especially if
that occurred over an urbanized area.

Lamers

ATTN...WFO...DDC...ICT...OUN...TOP...

ATTN...RFC...ABRFC...MBRFC...

LAT...LON   39229653 38449644 37429811 36839969 37429993
            38319892 38959771