Had some pretty hard rain. Flash flooding possible tonight.
Mesoscale Precipitation Discussion 0072
NWS Weather Prediction Center College Park MD
433 PM EST Wed Feb 22 2023
Areas affected...central/northern IL into northern IN,
northwestern OH and southern MI
Concerning...Heavy rainfall...Flash flooding possible
Valid 222130Z - 230330Z
SUMMARY...Heavy rain will continue a threat for flooding from
central/northern IL into northern IN and extreme northwestern
OH/southern MI. Peak rainfall rates of just over 1 in/hr will
allow for an additional 1 to 2 inches of rain through 03Z, but
rainfall intensity is expected to decrease with time.
DISCUSSION...Regional radar imagery at 21Z showed a broad shield
of precipitation extending to the north and northeast of a surface
low analyzed over central IL. Localized reports of 1+ in/hr have
occurred across portions of central IL over the past few hours
where the SPC mesoanalysis indicated MUCAPE near 100 J/kg and
precipitable water values of 1.2 to 1.4 inches. MRMS and gauge
reports indicated 1 to 3 inches of rain has fallen over the past
12 hours from central IL into north-central IN. Across far
northern IN/OH into southern MI, surface temperatures near 32 have
supported areas of freezing rain with the freezing line expected
to only marginally lift north over the next few hours.
As a negatively tilted shortwave over the mid-Mississippi Valley
continues to advance northeastward, it is expected to maintain a
weakening trend and support the ENE track of the surface low over
central IL toward northwestern OH. South-southwesterly 850 mb
winds of 50 to 60 kt just ahead of the shortwave and surface low
are expected to continue strong ascent over a well-defined warm
front extending eastward from the low. Elevated instability is
only about 100-200 J/kg according to the 20Z SPC mesoanalysis but
is forecast to gradually lower over the next 3-6 hours which
should reduce peak rainfall intensity to 0.5 to 0.75 in/hr beyond
00Z.
An additional 1-2 inches of rain is expected through 03Z, with
rainfall ending from west to east. Expected rainfall should near
area 3-hr flash flood guidance of 1 to 1.5 inches, but should
primarily lie north of the axis of heavy rain that has fallen over
the past 12 hours. Nonetheless, localized areas of flooding will
be possible, within a fairly narrow corridor between the warm
front and frozen precipitation to the north over southern MI.
Otto