SUMMARY...Flash flooding will be likely going through the morning
hours from locally training thunderstorms that will be capable of
producing 1 to 2 inch/hour rainfall rates. Additional rainfall
totals of 2 to 4 inches with isolated heavier totals will be
possible by midday, with a threat for locally significant urban
flash flooding impacts as a result.
DISCUSSION...Radar and satellite imagery shows a well-defined axis
of heavy showers and thunderstorms impacting portions of northern
and eastern KS, with activity very quickly advancing into
northwest MO. This includes the Topeka and Kansas City
metropolitan areas. Deep convection with cold convective tops as
low as -70C are noted across the region, and the activity is
exhibiting several overshooting tops which is indicative of
particularly strong convective updrafts and enhanced rain rates.
The activity continues to advance generally off to the east in
association with an ejecting shortwave trough across western and
central KS with excellent divergence aloft working in tandem with
a southwest low-level jet of 50 to 60 kts around the southeast
flank of multiple waves of surface low pressure. These ejecting
waves of low pressure are helping to channel enhanced moisture and
instability transport across eastern KS and into western and
northern MO as a warm front gradually gains latitude downstream
across central MO and southern IL.
MUCAPE values are as high as 2000 to 3000 J/kg with PWs locally as
high as about 1.5 inches across eastern KS and nosing through
northern MO. This favorable thermodynamic environment coupled with
enhanced kinematic wind fields/shear will strongly support a
continuation of organized MCS activity traversing the Lower MO
Valley this morning with convection likely becoming more
concentrated by mid-morning across north-central MO and eventually
into areas of west-central IL.
Rainfall rates will easily be into the 1 to 2 inch/hour range, and
with an excellent cell-training environment, some additional
rainfall totals of 2 to 4 inches with isolated heavier amounts
will be possible. Flash flooding is already occurring over parts
of east-central and northeast KS through west-central MO including
the Topeka and Kansas City metropolitan areas. Additional rounds
of heavy rainfall over the next couple of hours here will support
the potential for significant urban flash flooding impacts.
Areas downstream across north-central MO and eventually
west-central IL will likely see the threat for at least some flash
flooding increase through the morning hours.