Mesoscale Precipitation Discussion 0940
NWS Weather Prediction Center College Park MD
1045 PM EDT Sun Oct 07 2018

Areas affected...Southwest to North-Central OK...South-Central to
Eastern KS

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

Valid 080245Z - 080845Z

Summary...An axis of very heavy rainfall is expected overnight
with flash flooding likely from areas of southwest to
north-central OK and into south-central and eastern KS.

Discussion...The latest IR satellite imagery shows an expansive
axis of cold convective tops impacting areas of southwest to
north-central OK and up across south-central and eastern KS as
strong deep layer southerly flow ahead of an upper trough/closed
low over the Southwest U.S. helps to transport anomalous moisture
and plenty of instability northward across the Plains. Much of the
convection has been focusing north of a well-defined frontal zone
draped across the region with a combination of elevated
instability and isentropic ascent pooled across the region.

The latest blended-TPW product and GPS-derived data shows PWATs
approaching 1.75 inches across the threat area which is 2 to 2.5
standard deviations above normal for this time of the year, and
this will favor rather efficient rainfall processes for enhanced
rainfall rates overnight. In some cases, hourly rainfall amounts
may approach 2 inches.

The large scale pattern will favor an expansive axis of heavy
showers and thunderstorms overnight and with a very strong signal
for repeating/training convection north of the front. The latest
HRRR guidance favors additional rainfall amounts of 3 to 4 inches,
which may be locally underdone given the degree of convective
organization seen just north of the front. Given the increasingly
wet antecedent conditions and additional rainfall totals, flash
flooding will be likely.

Orrison

ATTN...WFO...DDC...EAX...ICT...OUN...SGF...TOP...TSA...

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

LAT...LON   39179529 38729463 37759511 37119576 36579630
            35959707 35279802 34849873 34639926 34529959
            34629989 34909993 35549987 36029965 36629937
            37179894 37949807 38609727 38989653