286
AWUS01 KWNH 140831
FFGMPD
MOZ000-IAZ000-KSZ000-NEZ000-141430-

Mesoscale Precipitation Discussion 0880
NWS Weather Prediction Center College Park MD
430 AM EDT Wed Aug 14 2024

Areas affected...Eastern NE...Southwest IA...Northwest and Central
MO

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

Valid 140830Z - 141430Z

SUMMARY...Expanding areas of heavy showers and thunderstorms with
some cell-training concerns will likely result in some areas of
flash flooding heading through the mid morning hours.

DISCUSSION...The late-night GOES-E IR satellite imagery shows a
strong cold-topped MCS continuing to advance east across the
central Plains with the axis of heaviest rainfall currently moving
across areas of eastern NE and far southwest IA. This MCS
continues to traverse the north side of a strong elevated
instability gradient and has a well-defined MCV associated with it
which is expected to continue to advance east this morning across
eastern NE.

Strong warm air advection around the southeast side of the MCS and
its related mid-level vort energy is expected to foster an
expansion of heavy shower and thunderstorm activity downstream
across areas of southeast NE, southwest IA and areas of northwest
to central MO over the next few hours. This will be aided by a
southwest low-level jet of 40+ kts which will yield strengthening
isentropic ascent along with a focused corridor of stronger
moisture and instability transport. MUCAPE values are as high as
2000 to 3000 J/kg along the NE/KS border and this instability will
favor the evolution of multiple elevated convective bands that
will tend to be generally aligned nearly parallel to the deeper
layer steering flow. Consequently, there will be concerns for
cell-training.

PWs are quite high and generally in the 1.75 to 2.0 inch range,
and this coupled with the available instability and improving
shear parameters early this morning should favor rainfall rates of
as much as 1.5 to 2.5 inches/hour with the stronger storms.

The cell-training concerns may foster some rainfall totals by mid
morning that reach 3 to 5 inches, and the 00Z HREF guidance
suggests that the main focus for the heaviest rains should tend to
be over areas of southwest IA down through northwest and central
MO. Given this and the recent moistening of the antecedent
conditions from recent rainfall, some areas of flash flooding will
be likely to occur.

Orrison

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

ATTN...WFO...DMX...EAX...LSX...OAX...SGF...

ATTN...RFC...MBRFC...NCRFC...NWC...

LAT...LON   41989624 41559436 40469289 38279162 38439232
            38789332 38979428 40039529 41369674