Mesoscale Precipitation Discussion 0715
NWS Weather Prediction Center College Park MD
130 AM EDT Fri Aug 24 2018

Areas affected...Central and Northern MO...Southern IA...Western
IL

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

Valid 240530Z - 241130Z

Summary...Expect showers and thunderstorms to continue to develop
with an increasing threat for back-building storms raising the
threat for heavy amounts.

Discussion...Convection has begun to develop within an area of
deep moisture (PWs 1.9-2.1 inches) and elevated instability across
northern Missouri.  Amplifying southwesterly flow ahead of a
shortwave trough moving across the northern and central Plains is
expected to support a further increase in moisture and instability
across the region over the next several hours, with recent runs of
the RAP showing PWs increasing to at or above 2 inches along a
40-50 kt southwesterly 850mb jet across central into northern
Missouri and southern Iowa overnight.  This along with increasing
lift ahead of an upper level speed max is expected to support
further storm development overnight.  Initial storms are forecast
to move steadily across northern Missouri, however as the low
level level flow increases, propagation vectors suggest an
increasing threat for back-building storms from southern Iowa and
northern Missouri back into central Missouri.  For the 6-hr period
ending 12z, HREF neighborhood probabilities are above 50 percent
for amounts of an inch or more across much of the highlighted
region and are greater than 50 percent for amounts of 2 inches or
more across northeast Missouri.

Pereira

ATTN...WFO...DMX...DVN...EAX...ILX...LSX...SGF...

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

LAT...LON   41409290 40429084 38209166 37679414 39219376
            40399459